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Mina, Grace Asoka, Orkwagh Abu Gideon, and Kenechukwu Agwa Obioma. "A Kinetic model for submerged citric acid production by Aspergillus versicolor using oil palm empty fruit bunch." GSC Biological and Pharmaceutical Sciences 17, no. 1 (2021): 033–40. https://doi.org/10.5281/zenodo.5599121.
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The fermentation kinetics of citric acid by <em>Aspergillus versicolor</em> was studied in a submerged batch system. The logistic equation for growth, the Luedeking–Piret equation for citric acid production and modified Luedeking–Piret-like equation for glucose consumption was proposed for this study. The model appeared to provide a reasonable description for each parameter during the growth phase. The production of citric acid was growth-associated.
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Hu, Zhong Ce, Guo Feng Jiang, and Yu Guo Zheng. "A Kinetic Model for Astaxanthin Fermentation by Xanthophyllomyces Dendrorhous Zjut46." Advanced Materials Research 343-344 (September 2011): 397–402. http://dx.doi.org/10.4028/www.scientific.net/amr.343-344.397.
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Astaxanthin, a main carotenoid pigment, has a strong antioxidant activity. A kinetics of astaxanthin fermentation by Xanthophyllomyces dendrorhous was studied in a batch fermentation system. The unstructured models were proposed using the Logistic equation for microbial growth, the Luedeking-Piret equation for astaxanthin production and Luedeking-Piret-like equation for glucose consumption. The production of astaxanthin was partly growth-associated. Compared with the experimental data and calculated data, most of errors were lower than 10 %, it showed that the proposed unstructured models were adequate to describe the fermentation bioprocess of astaxanthin by X. dendrorhous.
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Mina Grace Asoka, Gideon Orkwagh Abu, and Obioma Kenechukwu Agwa. "A Kinetic model for submerged citric acid production by Aspergillus versicolor using oil palm empty fruit bunch." GSC Biological and Pharmaceutical Sciences 17, no. 1 (2021): 033–40. http://dx.doi.org/10.30574/gscbps.2021.17.1.0301.
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The fermentation kinetics of citric acid by Aspergillus versicolor was studied in a submerged batch system. The logistic equation for growth, the Luedeking–Piret equation for citric acid production and modified Luedeking–Piret-like equation for glucose consumption was proposed for this study. The model appeared to provide a reasonable description for each parameter during the growth phase. The production of citric acid was growth-associated.
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Mandal, Barnali. "STUDY THE GROWTH KINETICS OF PEDIOCOCCUS ACIDILACTICI WITH ESTIMATION OF KINETIC PARAMETERS AND APPLIED IN LARGE SCALE PEDIOCIN PRODUCTION." Asian Journal of Pharmaceutical and Clinical Research 9, no. 5 (2016): 130. http://dx.doi.org/10.22159/ajpcr.2016.v9i5.12753.
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ABSTRACTObjectives: The aim of the study was to determine the growth kinetics of Pediococcus acidilactici using a mathematical model for large scale pediocinproduction.Methods: Growth kinetics of P. acidilactici has been studied for pediocin production in small scale batch fermenter (Erlenmeyer flask) using meatprocessing waste medium. The experiments have been conducted with varying the concentrations of glucose, protein, and lactic acid. A mathematicalmodel has been developed to describe growth rate, products (pediocin and lactic acid) formation rate, and substrates (glucose and protein) utilizationrate. Monod model for dual substrates (glucose and protein) has been used with considering lactic acid inhibition. Luedeking-Piret model has beenintroduced to describe the production of pediocin and lactic acid.Results: The values of kinetic parameters have been determined using experimental data and model equations. The model prediction has beencompared satisfactorily with the experimental data for the validation of the model.Conclusions: The developed model was satisfactorily validated to scale up the production of pediocin.Keywords: Pediococcus acidilactici, Pediocin, Meat processing waste, Monod model, Luedeking-Piret model, Kinetic parameters.
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Goranov, Bogdan, Vesela Shopska, Rositsa Denkova, and Georgi Kostov. "Kinetics of Batch Fermentation in the Cultivation of a Probiotic Strain Lactobacillus Delbrueckii Ssp. Bulgaricus B1." Acta Universitatis Cibiniensis. Series E: Food Technology 19, no. 1 (2015): 61–72. http://dx.doi.org/10.1515/aucft-2015-0006.
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AbstractA comparative study of kinetic models to describe the dynamics of the fermentation process of culturing of a probiotic strain Lactobacillus delbrueckii ssp. bulgaricus B1 was performed. The models of Monod, Aiba, Tiessier, Hinshelwood and the equation of the logistic curve combined with the model of Ludeking-Piret were used. It has been found that the different models described the observed fermentation dynamics differently. The conducted comparative study demonstrated that the models of Monod and the equation of the logistic curve combined with the model of Ludeking-Piret were suitable for the description of the fermentation dynamics. The mathematical models showed no significant product and/or substrate inhibition. The culture developed with a low specific growth rate, but nevertheless it accumulated 1012-1013viable cells. The substrate was absorbed primarily from cells in the stationary growth phase rather than cells in the exponential growth phase
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Gao, Shuang, Ling Hua Zhang, Qing Chen, Lin Bai, and Ya Jun Lang. "The Study of the Kinetic Model of Halomonas Salina Fermenting Ectoine." Advanced Materials Research 781-784 (September 2013): 647–52. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.647.
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Ectoine had important physiological functions and superior potential applications, so the study of ectoine was extensively attented. This article was related to kinetic models of cell growth, product formation and substrate consumption, which was not only established according to the characteristics of ectoine batch fermentation by Halomonas salina DSM 5928 but also obtained the kinetic parameters by the nonlinear fitting method in the Microcal Origin software. Logistic, Luedeking-Piret and Luedeking-Piret-like equations was applied to analyze the cell growth, the ectoine formation and the substrate consumption by the kinetic model，respectively. The results between calculated values and experimental data were coincident. By fitting, correlation coefficients R2 were ≥ 0.989. The fermentation conditions of ectoine were analyzed according to the model. The results showed that ectoine productivity (0.28 g/L/h) was the highest when initial monosodium glutamate concentration (S0) was 60 g/L. However, when S0 was 80 g/L, the ectoine concentration was maximal, i.e., 7.59 g/L. The research suggested that ectoine formation belonged to the mixed kinetic mechanism of cell growth and biomass concentration, while the ectoine production mainly depended on instantaneous biomass concentration. The fermentation method for improving ectoine concentration was further proved. The established kinetic model will be of significant value to provide the optimal conditions of present process.
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Gilani, S. L., G. D. Najafpour, H. D. Heydarzadeh, and H. Zare. "Kinetic models for xanthan gum production using Xanthomonas campestris from molasses." Chemical Industry and Chemical Engineering Quarterly 17, no. 2 (2011): 179–87. http://dx.doi.org/10.2298/ciceq101030002g.
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In process of xanthan gum production the effect of media temperature, agitation rate and molasses concentration on yield of fermentation were investigated. Xanthan gum was produced in batch fermentation by Xanthomonas campestris PTCC 1473 from molasses. At 32?C, 500 rpm and media with 30g/l of total sugar maximum production of xanthan gum (17.1g/l) was achieved. For the purity of the xanthan FTIR spectrum was obtained. The identified spectrum was compared with the commercial product. In batch culture, several kinetic models for the biochemical reactions were extensively studied. The growth kinetic parameters were evaluated by unstructured model and derived from the related equations. Based on Malthus and Logistic rate equations, the maximum specific growth rate, ?max, and initial cell dry weight, X0, were defined. Luedeking-Piret and Modified Luedeking-Piret models were applied for the product formation and substrate consumption rates. In batch experiments, the kinetic parameters for the growth associated (m, a) and non-growth associated (n, b) parameters were determined.
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Kingsley Chidozie Agu and Mujeeb Koyejo Oduola. "Kinetic modeling of ethanol production by batch fermentation of sugarcane juice using immobilized yeast." Global Journal of Engineering and Technology Advances 7, no. 1 (2021): 124–36. http://dx.doi.org/10.30574/gjeta.2021.7.1.0060.
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Ethanol production via the batch fermentation of sugarcane juice using immobilized yeast has been studied. The influence of glucose concentration, ethanol concentration, and cell concentration (biomass) on the process rate throughout the period of fermentation has been investigated. Initial cell concentration was found to be 4.60 g/L saccharomyces cerevisiae. Biomass, ethanol and glucose concentrations were measured at different time interval during fermentation. The experimental data obtained were fitted using a variety of models for yeast growth. The logistic model gave the best fitting and was the basis for the development of the overall kinetic model. For ethanol formation, different model based on the logistic model for yeast growth were used to fit the experimental data and the leudeking – piret model was adopted because of its good fit. The leudeking – piret model was also adopted for substrate consumption. The estimated values of the kinetic parameters in the developed model were μm=0.04216hr-1, Xm = 6.2652g/L, α = 24.87149g/g.hr, Yx/s = 0.18292g/g and m = 0.008171g/g.hr. Therefore, a model based on the logistic equation of yeast growth, growth associated production of ethanol, and consumption of glucose for biomass and maintenance was found to accurately fit the production of ethanol from sugarcane.
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Kingsley, Chidozie Agu, and Koyejo Oduola Mujeeb. "Kinetic modeling of ethanol production by batch fermentation of sugarcane juice using immobilized yeast." Global Journal of Engineering and Technology Advances 7, no. 1 (2021): 124–36. https://doi.org/10.5281/zenodo.4724741.
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Ethanol production via the batch fermentation of sugarcane juice using immobilized yeast has been studied. The influence of glucose concentration, ethanol concentration, and cell concentration (biomass) on the process rate throughout the period of fermentation has been investigated. Initial cell concentration was found to be 4.60 g/L saccharomyces cerevisiae. Biomass, ethanol and glucose concentrations were measured at different time interval during fermentation. The experimental data obtained were fitted using a variety of models for yeast growth. The logistic model gave the best fitting and was the basis for the development of the overall kinetic model. For ethanol formation, different model based on the logistic model for yeast growth were used to fit the experimental data and the leudeking – piret model was adopted because of its good fit. The leudeking – piret model was also adopted for substrate consumption. The estimated values of the kinetic parameters in the developed model were μ<sub>m</sub>=0.04216hr<sup>-1</sup>, X<sub>m</sub> = 6.2652g/L, α = 24.87149g/g.hr, Yx/s = 0.18292g/g and m = 0.008171g/g.hr. Therefore, a model based on the logistic equation of yeast growth, growth associated production of ethanol, and consumption of glucose for biomass and maintenance was found to accurately fit the production of ethanol from sugarcane.
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Ezhumalai, Sasikumar, and Viruthagiri Thangavelu. "Kinetic and optimization studies on the bioconversion of lignocellulosic material into ethanol." BioResources 5, no. 3 (2010): 1879–94. http://dx.doi.org/10.15376/biores.5.3.1879-1894.
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In the present study, classical statistical tool Response Surface Methodology (RSM) was adopted for the optimization of process variables in the bioconversion of pretreated sugarcane bagasse into ethanol by cellulase and Candida wickerhamii MTCC 3013 based on Central Composite Design (CCD) experiments. A 23 five level CCD with central and axial points was used to develop a statistical model for the optimization of process variables such as incubation temperature (25 – 45°) X1, pH (5.0 – 7.0) X2,and fermentation time (24 – 120 h) X3. Data obtained from RSM on ethanol production were subjected to analysis of variance (ANOVA) and analyzed using a second-order polynomial equation, and isoresponse contour plots were used to study the interactions among three relevant variables. Maximum response for ethanol production was obtained when applying the optimum values for temperature (33°C), pH (5.7), and fermentation time (104 h). Maximum ethanol concentration (4.28 g/l) was obtained from 50 g/l pretreated sugarcane bagasse at the optimized process conditions in aerobic batch fermentation. Various kinetic models such as Modified Logistic model, Modified Logistic incorporated Leudeking – Piret model, and Modified Logistic incorporated Modified Leudeking – Piret model were evaluated and the constants were predicted.
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Zafar, Mohd, Shashi Kumar, Surendra Kumar, Jay Agrawal, and Amit K. Dhiman. "Valorization of Glycerol into Polyhydroxyalkanoates by Sludge Isolated Bacillus sp. RER002: Experimental and Modeling Studies." Chemical Product and Process Modeling 9, no. 2 (2014): 117–31. http://dx.doi.org/10.1515/cppm-2014-0011.
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Abstract In this study, the feasibility of glycerol valorization into homo- and hetero-polymers of polyhydroxyalkanoates by a sludge isolated Bacillus sp. RER002 in a 3 L bioreactor was investigated. A mathematical model including logistic, Luedeking–Piret, and Luedeking–Piret-like equations that simulated the active residual biomass growth, P(3HB) synthesis, and glycerol consumption, respectively, was developed. In order to describe the dynamics of batch P(3HB) production, the model kinetic parameters viz., µmax, K1, K2, α, β, and KN were optimized using the stochastic search-based genetic algorithm. The synthesis of P(3HB) wasobserved to be highly growth associated and partially non-growth associated as reflected in a significant higher values of K1 (0.2435–0.5477) than K2 (2.2 × 10−6 to 9.1 × 10−3) within the glycerol concentration range of 10–40 g/L. Besides, the maximum 3.2g/L of copolymer [P(3HAscl-co-3HAmcl)] was observed at 30 g/L of glycerol concentration in synthetic crude glycerol medium with a yield coefficient (YP/S) of 0.16 g/g. Furthermore, the analyses of chemical and thermal properties of copolymer P(3HAscl-co-3HAmcl) revealed its enhanced material properties which make it suitable for various applications.
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Germec, Mustafa, Irfan Turhan, Mustafa Karhan, and Ali Demirci. "Kinetic Modeling and Techno-economic Feasibility of Ethanol Production From Carob Extract Based Medium in Biofilm Reactor." Applied Sciences 9, no. 10 (2019): 2121. http://dx.doi.org/10.3390/app9102121.
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In this study, different carob extract-based media containing Medium A (included all ingredients), Medium B (included yeast extract and salts), Medium C (included (NH4)2SO4 and salts), Medium D (included only salts) and Medium E (included no ingredients) were evaluated for ethanol fermentation by Saccharomyces cerevisiae in a biofilm reactor and their results were used for kinetic modeling. The logistic model for cell growth, Luedeking-Piret model for ethanol production and Modified Luedeking-Piret model for substrate consumption were studied. Kinetic parameters were determined by fitting the observed values of the models. The findings indicated that the predicted data with the suggested kinetic model for each medium fitted very well the experimental data. Estimated kinetics were also in good agreement with experimental kinetics. The techno-economic analysis was performed with the unit costs of the components used in the medium and ethanol. Medium-based process economic feasibility proved carob extract-based Medium E and subsequently Medium D as most economical for ethanol production. The present study verified the potential of carob extract-based medium for increased economical production of ethanol. In conclusion, the ethanol production in a biofilm reactor is growth-associated since α (gP/gX) was greater than β (gP/gX.h) and Media D and E increased the economic production of carob extract-based ethanol.
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Ghimire, Arjun, and Stuti Sapkota. "Modelling the kinetics of biomass and lactic acid production during Rohu fish pickle fermentation." Malaysian Journal of Chemical Engineering and Technology (MJCET) 3, no. 1 (2020): 7. http://dx.doi.org/10.24191/mjcet.v3i1.10940.
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Fish pickle was prepared from Rohu (Labeo rohita) by fermentation for 15 days and the changes in biomass growth, lactic acid production, and pH were evaluated. The data obtained were fitted in two most widely accepted microbial growth models: Modified Gompertz, and Logistic model and three well known lactic acid production models: Luedeking-Piret, Monteagudo et al., and Balannec et al. model for lactic acid fermentation. Model constants and coefficients were determined by a nonlinear regression method. All the models were validated using statistical parameters namely, coefficient of determination (R2), root mean square error (RMSE), reduced chi-square (χ2) and the reduced sum of squares (RSS). The results revealed that the viable cell counts increased from 0.91×107 cfu/ml to 9×109 cfu/ml after nine days of fermentation. The lactic acid increased by about 11.6 times in 12 days and remained constant for the rest of the fermentation period. The pH decreased from 6.5 to 4.2 on the 15th day of fermentation and then increased slightly till the final day of fermentation. The Logistic model and Luedeking-Piret model were best fitted to describe the biomass growth and lactic acid production by LAB during the fermentation period of pickle. The growth-associated and non-growth associated coefficients were determined to be 0.813 and 0.005, respectively. Based on these estimated parameters, it is concluded that lactic acid production in the fish pickle was a mixed type.
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Abd-Elsalam, Ibrahim S., Mona S. Shafei, Reda F. Allam, et al. "Kinetic model for polyhydroxybutyrate production by Bacillus aryabhattai MH997667.1 in a batch culture using different agitation speeds." Egyptian Pharmaceutical Journal 23, no. 2 (2024): 272–78. http://dx.doi.org/10.4103/epj.epj_167_23.
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Background Slow degradation of synthetic plastics represents a high environmental hazard; therefore, there is an essential requirement to substitute them with eco-friendly products. Polyhydroxybutyrate (PHB) is a biodegradable biopolymer and also has several industrial, agricultural, and medical applications. Scaling up the production of PHB is still a problem due to the numerous parameters tangled in the fermentation processes. Objective The present work seeks to scale up polyhydroxybutyrate production by Bacillus aryabhattai MH997667.1 from shaken flasks to a 5L-bench top bioreactor with previously optimized media by applying a batch fermentation strategy. Materials and methods Different agitation speeds (200, 250 and 300 rpm) were tested in a 5L-bench-top bioreactor with a working volume of 3L. A kinetic model (logistic and Luedeking–Piret) that describes the microbial biomass and polyhydroxybutyrate (PHB) production is used to expect the performance of batch fermentation of Bacillus aryabhattai MH997667.1. Results and conclusion The optimum PHB yield (2.32 g/l) was expressed at 250 rpm agitation after 28 hours of fermentation. The experimental data were also fitted with the logistic and Luedeking–Piret equations for growth and PHB formation, respectively. The mathematical model proposed for batch fermentation revealed that the simulated data showed a good fit with the experimental results obtained during the first 24 h of PHB production at 250 rpm, where the productivity was 0.095 g L−1h−1. Our data suggest that agitation speed had a significant effect on PHB production and the 250 rpm agitation speed is the optimum speed for PHB production using Bacillus aryabhattai MH997667.1 in batch fermentation.
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Bajic, Bojana, Damjan Vucurovic, Sinisa Dodic, Zorana Roncevic, Jovana Grahovac, and Jelena Dodic. "The biotechnological production of xanthan on vegetable oil industry wastewaters (part II): Kinetic modelling and process simulation." Chemical Industry and Chemical Engineering Quarterly 24, no. 2 (2018): 127–37. http://dx.doi.org/10.2298/ciceq170310004b.
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Xanthan is a microbial biopolymer with a wide range of industrial applications and it is expected that the demand for this product will significantly increase in the coming decade and for this reason it is important to constantly work on improving all aspects of this biotechnological process. The aim of this research was to examine the kinetics of batch cultivation of Xanthomonas campestris ATCC 13951 using vegetable oil industry wastewaters as a basis for the cultivation medium, in order to produce the biopolymer xanthan. Kinetic modelling is very important for process control, reducing process costs and increasing product quality. By performing xanthan production on a medium with optimized content, the experimental values of content of biomass, carbon source and the desired product were obtained and used to determine the kinetics of biosynthesis. In order to describe biomass multiplication, product formation and carbon source consumption, the logistics, the Luedeking-Piret and modified Luedeking- -Piret equation, respectively, were successfully used. Additionally, using process simulation software (SuperPro Designer?), a process and cost model for a xanthan production facility was developed. The developed model represents the basis for a 21,294.29 and 23,107.97 kg/year xanthan production facility, which uses a vegetable oil industry wastewater-based medium and a semi-synthetic medium. The simulation model of the suggested xanthan production process, developed and based on defined kinetic models, represents an excellent basis for its further improvement and for increasing its efficiency.
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Kanzariya, R., A. Gautam, S. Parikh, and S. Gautam. "Kinetics of biomass and polyhydroxyalkanoates synthesis using sugar industry waste as carbon substrate by Alcaligenes sp. NCIM 5085." Journal of Environmental Biology 44, no. 4 (2023): 612–22. http://dx.doi.org/10.22438/jeb/44/4/mrn-5096.
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Aim: o optimize the operating parameters and further determine the kinetics of biomass and polyhydroxyalkanoate synthesis using sugar industry waste as a carbon substrate by Alcaligenes sp. NCIM 5085. Methodology: Molasses, clarified and pretreated with sulphuric acid, was taken in a batch reactor for fermentation to generate biomass and further for polyhydroxyalkanoate synthesis where Alcaligenes sp. NCIM 5085 was used as a culture. A number of parameters were observed during fermentation experiments to optimize the biomass and PHA namely: initial substrate concentration, incubation period, C/N ratio, inoculum concentration and pH. Fermented solution was filtered to account the yield of biomass from the solution at each time interval decided for each experiment and polyhydroxyalkanoate was extracted from the biomass by chloroform and methanol extraction. Growth kinetics of biomass was modeled by Monod and Logistic models whereas Luedeking-Piret model was used for polyhydroxyalkanoate production rates. Results: From the fermentation experiments, it was found that for 40 g l-1 of molasses at neutral pH, 4.48 g l-1 of biomass was synthesized when fermentation was observed for 48 hr. One percent of cell dry weight of biomass was extracted as polyhydroxyalkanoate. Logistic model for growth kinetics and Luedeking-Piret model for polyhydroxyalkanoate production rate were found in agreement with the experiments where regression coefficient was maximum with minimum error. Interpretation: The PHA growth kinetics and PHA production kinetics done in this work can be utilized to design a bioreactor for PHA production at industrial scale. Key words: Alcaligenes sp., Biomass, Cane molasses, Growth kinetics, Polyhydroxyalkanoates
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Orji, Justina, Chima Ngumah, Hanna Asor, and Anulika Anuonyemere. "Effects of cobalt and manganese on biomass and nitrogen fixation yields of a free-living nitrogen fixer - Azotobacter chroococcum." European Journal of Biological Research 8, no. 1 (2018): 7–13. https://doi.org/10.5281/zenodo.1157098.
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The effects of different concentrations of cobalt and manganese on the biomass and the ability of <em>Azotobacter chroococcum</em> to fix nitrogen were investigated. <em>In vitro</em> trials were conducted in Jensen’s (nitrogen free) broth (half strength) under continuous air flow, incubated at ambient room temperatures for seven days. Results obtained showed that 12.5 mg/l, 25 mg/l, 50 mg/l, 100 mg/l, and 200 mg/l concentrations of cobalt and manganese respectively enhanced microbial growth of <em>Azotobacter chroococcum</em> concomitantly. However, nitrogen fixation was enhanced only at 12.5 mg/l and 25 mg/l concentrations for cobalt, and only at 12.5 mg/l concentration for manganese. Statistical analysis revealed no significant difference in the specific growth rates and nitrogen fixations respectively, between the cobalt and manganese trials. Kinetic modeling revealed that nitrogen fixation was associated with biomass concentration, and not with cell mass growth.
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Urniezius, Renaldas, and Arnas Survyla. "Identification of Functional Bioprocess Model for Recombinant E. Coli Cultivation Process." Entropy 21, no. 12 (2019): 1221. http://dx.doi.org/10.3390/e21121221.
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The purpose of this study is to introduce an improved Luedeking–Piret model that represents a structurally simple biomass concentration approach. The developed routine provides acceptable accuracy when fitting experimental data that incorporate the target protein concentration of Escherichia coli culture BL21 (DE3) pET28a in fed-batch processes. This paper presents system identification, biomass, and product parameter fitting routines, starting from their roots of origin to the entropy-related development, characterized by robustness and simplicity. A single tuning coefficient allows for the selection of an optimization criterion that serves equally well for higher and lower biomass concentrations. The idea of the paper is to demonstrate that the use of fundamental knowledge can make the general model more common for technological use compared to a sophisticated artificial neural network. Experimental validation of the proposed model involved data analysis of six cultivation experiments compared to 19 experiments used for model fitting and parameter estimation.
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Barnali, Mandal, and Chakraborty Aditia. "Pediocin production by Pediococcus acidilactici in fed batch fermentation using meat processing waste." Journal of Indian Chemical Society Vol. 97, Jun 2020 (2020): 903–9. https://doi.org/10.5281/zenodo.5664273.
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Department of Chemical Engineering, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata-700 009, India <em>E-mail:</em> bmandal20@yahoo.co.in <em>Manuscript received online 12 January 2020, revised and accepted 22 May 2020</em> Pediocin production by <em>Pediococcus acidilactici</em> was studied in a bio-reactor under two fed batch fermentations (fed batch operation I and fed batch operation II) at constant pH condition using meat processing waste. In fed batch operation II, higher pediocin activity of 4572 AU/ml was achieved comparing to fed batch operation I (pediocin activity of 3657 AU/ml). The kinetics of cell growth was described by two substrates (glucose and protein) model. The correlation between two products (pediocin and lactic acid) and cell growth was described by Luedeking and Piret model. The comparison of simulated data with experimental results obtained from the study was well matched and the validated mathematical model was developed for fed batch processes.
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Sun, Wen Jing, Lin Yu, Si Lian Yu, et al. "Kinetic Modeling of 2-Keto-Gluconic Acid (2KGA) Production from Rice Starch Hydrolysate Using Pseudomonas fluorescens AR4." Advanced Materials Research 550-553 (July 2012): 1144–50. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.1144.
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Kinetic models are proposed for the 2KGA batch production from rice starch hydrolysate containing 162 g/L of glucose by Pseudomonas fluorescens AR4. The models include terms accounting for both substrate and product inhibitions. Experimental data collected from the batch fermentations were used to estimate parameters and also to validate the models proposed. The growth of Ps. fluorescens could be expressed by a Logistic model wihout incorporating inhibitions of glucose and organic acids accumulated in the culture broth. The Luedeking–Piret model was able to describe the 2KGA formation as the fermentation proceeded with a mixed-growth-associated pattern. In all cases, the model simulation matched well with the experimental observations, which made it possible to elucidate the fermentation characteristics of Ps. fluorescens AR4 during efficient 2KGA production from glucose.
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Groff, M. Carla, Gustavo Scaglia, Oscar A. Ortiz, and Sandra E. Noriega. "Modification of the Luedeking and Piret model with a delay time parameter for biotechnological lactic acid production." Biotechnology Letters 44, no. 3 (2022): 415–27. http://dx.doi.org/10.1007/s10529-022-03227-0.
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Groff, Carla, Benjamín Kuchen, Rocío Gil, Cecilia Fernández, and Gustavo Scaglia. "Application of the Luedeking and Piret with delay time model in bioproductions with non-zero kinetic parameters." IEEE Latin America Transactions 21, no. 8 (2023): 882–88. http://dx.doi.org/10.1109/tla.2023.10246344.
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Thierie, Jacques. "Computing and Interpreting Specific Production Rates in a Chemostat in Steady State According to the Luedeking-Piret model." Applied Biochemistry and Biotechnology 169, no. 2 (2012): 477–92. http://dx.doi.org/10.1007/s12010-012-9978-z.
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Kreft, J. U., and J. W. Wimpenny. "Effect of EPS on biofilm structure and function as revealed by an individual-based model of biofilm growth." Water Science and Technology 43, no. 6 (2001): 135. http://dx.doi.org/10.2166/wst.2001.0358.
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We have simulated a nitrifying biofilm with one ammonia and one nitrite oxidising species in order to elucidate the effect of various extracellular polymeric substance (EPS) production scenarios on biofilm structure and function. The individual-based model (IbM) BacSim simulates diffusion of all substrates on a two-dimensional lattice. Each bacterium is individually simulated as a sphere of given size in a continuous, three-dimensional space. EPS production kinetics was described by a growth rate dependent and an independent term (Luedeking-Piret equation). The structure of the biofilm was dramatically influenced by EPS production or capsule formation. EPS production decreased growth of producers and stimulated growth of non-producers because of the energy cost involved. For the same reason, EPS accumulation can fall as its rate of production increases. The patchiness and roughness of the biofilm decreased and the porosity increased due to EPS production. EPS density was maximal in the middle of the vertical profile. Introduction of binding forces between like cells increased clustering.
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Das, Prama, and Soham Chattopadhyay. "Process Improvisation Strategies for the Enhancement of Lipase Activity." Research Journal of Biotechnology 16, no. 7 (2021): 114–21. http://dx.doi.org/10.25303/167rjbt11421.
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In this present study, lipase-producing bacteria were isolated and screened from an indigenous soil sample and were used for lipase production with high enzyme activity. In the production medium, different production media were screened and lipase production was induced by olive oil, 14 mL/L. It was observed from Luedeking and Piret model that the lipase production was mixed growth associated with maximum activity at 37°C and at pH 7. Statistical optimization using Response Surface Methodology was performed to understand the interaction of different parameters and the standardized conditions obtained were as follows: Peptone 10 g/L, yeast extract 7.5 g/L and olive oil 14 mL/L. The predicted data were validated and the model predicted was significant with a maximum specific activity of 1.1 µmole/min/mg proteins. The lipasespecific activity was enhanced by 10% and 23% after a single parameter and statistical optimization.
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Guerra, Nelson Pérez, Paula Fajardo, Clara Fuciños, et al. "Modelling the Biphasic Growth and Product Formation byEnterococcus faeciumCECT 410 in Realkalized Fed-Batch Fermentations in Whey." Journal of Biomedicine and Biotechnology 2010 (2010): 1–16. http://dx.doi.org/10.1155/2010/290286.
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The influence of initial pH on growth and nutrient (total sugars, nitrogen, and phosphorous) consumption byEnterococcus faeciumCECT 410 was studied during batch cultures in whey. With these data, two realkalized fed-batch fermentations were developed using different feeding substrates. The shift from homolactic to mixed acid fermentation, the biphasic kinetics observed for cell growth and nitrogen consumption and the increase in the concentrations of biomass and products (lactic acid, acetic acid, ethanol, and butane-2,3-diol) were the most noteworthy observations of these cultures. Modelling the fed-batch growth ofEnt. faeciumwith the Logistic and bi-Logistic models was not satisfactory. However, biomass production was best mathematically described with the use of a double Monod model, which was expressed in terms of biomass, product accumulation, and nitrogen utilization. Product formation was successfully modelled with a modified form of the Luedeking and Piret model developed in this study.
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Eswari, Jujjavarapu Satya. "Therapeutic and Biodegradable Green Surfactant Kinetic Studies and Parameter Estimation with Multiple Substrates." Anti-Infective Agents 16, no. 2 (2018): 114–20. http://dx.doi.org/10.2174/2211352516666180528081950.
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Introduction: When environment polluted by complex petrochemical contaminants then prospective for biological treatment is needed. Methods: Biosurfactants exhibit biodegradability and anti-microbial properties hence efficacy of production and kinetics of in situ rhamnolipid production by Pseudomonas aeruginosa and lipopeptide production by Bacillus subtilis was carried out in a batch process. The need of the specific growth rate on carbon, nitrogen and phosphorous substrates was expected to monitor using Logistic, Monod, Moser and Contois type kinetic equation models. Impact of several bioprocess factors and optimization of control factors were studied. Results and Discussion: The simulation results show, Contois type model was better model than monod equation. Contois growth model says that bio mass rate depends upon the concentrations of substrate and biomass being inhibited at high concentrations of the biomass predicts, bio surfactant formation lowered with the high biomass concentration. Conclusion: The Luedeking Piret constants were calculated for rahamnolipid and lipopeptide production bearing in mind the cell survival maintenance from carbon, nitrogenand phosphorous substrates consumption. Assessed factors of this model specify that the formation of Rhamnolipid and lipopeptide was typically growth-associated.
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Mullai, P., Eldon R. Rene, and K. Sridevi. "Biohydrogen Production and Kinetic Modeling Using Sediment Microorganisms of Pichavaram Mangroves, India." BioMed Research International 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/265618.
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Mangrove sediments host rich assemblages of microorganisms, predominantly mixed bacterial cultures, which can be efficiently used for biohydrogen production through anaerobic dark fermentation. The influence of process parameters such as effect of initial glucose concentration, initial medium pH, and trace metal (Fe2+) concentration was investigated in this study. A maximum hydrogen yield of 2.34, 2.3, and 2.6 mol H2mol−1glucose, respectively, was obtained under the following set of optimal conditions: initial substrate concentration—10,000 mg L−1, initial pH—6.0, and ferrous sulphate concentration—100 mg L−1, respectively. The addition of trace metal to the medium (100 mg L−1FeSO4·7H2O) enhanced the biohydrogen yield from 2.3 mol H2 mol−1glucose to 2.6 mol H2mol−1glucose. Furthermore, the experimental data was subjected to kinetic analysis and the kinetic constants were estimated with the help of well-known kinetic models available in the literature, namely, Monod model, logistic model and Luedeking-Piret model. The model fitting was found to be in good agreement with the experimental observations, for all the models, with regression coefficient values >0.92.
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Widiyanti, Setyo Erna. "Studi Kinetika Konsumsi Glukosa oleh Aspergillus Niger dalam Produksi Bioethanol dari Lignoselulosa." INTEK: Jurnal Penelitian 4, no. 1 (2017): 14. http://dx.doi.org/10.31963/intek.v4i1.98.
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Global warming resulted from CO2 level increase in the atmosphere has caused elevation of earth temperature and uncertain climate changes. To prevent the rise of CO2 in the atmosphere can be done by using biomass fuel such as bioethanol. The raw materials of bioethanol can be derived from oil palm empty fruit bunch. Enzymatic hydrolysis utilizes cellulase-producing fungus and in this research, Aspergillus niger was chosen. The glucose produced is consumed by A niger as carbon source and this is undesirable, therefore it should be minimized as low as possible. Knowing the rate of glucose consumption is important to have a model of the hydrolysis reaction rate which will be helpful in the design process on an industrial scale hydrolysis reactor. This study aimed to determine the equations that can be used to approximate the growth rate of A. niger, glucose consumption, the formation of citric acid, and the kinetic parameters used to modeling the kinetics of glucose consumption by A. niger. Kinetics of glucose consumption by A. niger was studied in batch system with variation of initial glucose concentration of 30, 50, 70 g/l. The growth rate of A. niger, glucose consumption, and the formation of citric acid were modeled using 3 equations; i.e. Monod with non-competitive product inhibition, Luedeking-Piret, and Luedeking-Piret growth associated product formation, respectively. The values of kinetic parameters such as μmax, Ks, Kp, were 0.65 hour-1, 157.5 g/l, 0.3 g/l, for initial glucose concentration of 30, 50, 70 g/l, respectively. The values of α (kinetic parameter for growth associated product formation and α would be equal to Yp/x) and Yx/s were 0.4903, 0.8531, 0.9863; 0.5124, 0.2704, 0.2381, for initial glucose concentration of 30, 50, 70 g/l, respectively. Higher initial glucose concentration would increase α but it lowered Yx/s.
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Brandam, Cédric, Claudia Castro-Martínez, Marie-Line Délia, Felipe Ramón-Portugal, and Pierre Strehaiano. "Effect of temperature on Brettanomyces bruxellensis: metabolic and kinetic aspects." Canadian Journal of Microbiology 54, no. 1 (2008): 11–18. http://dx.doi.org/10.1139/w07-126.
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The effect of temperatures ranging from 15 to 35 °C on a culture of Brettanomyces bruxellensis was investigated in regards to thermodynamics, metabolism, and kinetics. In this temperature range, we observed an increase in growth and production rates. The growth behavior was well represented using the Arrhenius model, and an apparent activation energy of 16.61 kcal/mol was estimated. A stuck fermentation was observed at 35 °C as represented by high cell death. The carbon balance established that temperature had no effect on repartition of the glucose consumption between biomass and products. Hence, the same biomass concentration was obtained for all temperatures, except at 35 °C. Moreover, using logistic and Luedeking–Piret models, we demonstrated that production rates of ethanol and acetic acid were partially growth associated. Parameters associated with growth (αeth and αaa) remained constant with changing temperature, whereas, parameters associated with the population (βeth and βaa) varied. Optimal values were obtained at 32 °C for ethanol and at 25 °C for acetic acid.
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Vera-Peña, Madalyd Yurani, Hugo Hernández-García, and Francia Elena Valencia-García. "Kinetic modeling of lactic acid production, co-substrate consumptions and growth in Lactiplantibacillus plantarum 60-1." DYNA 89, no. 224 (2022): 50–57. http://dx.doi.org/10.15446/dyna.v89n224.102243.
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Lactiplantibacillus plantarum is a Gram-positive bacterium that belongs to the lactic acid bacteria (LAB) group commonly used in the food industry. To use this microorganism, high biomass concentration is necessary, and models need to be established for predicting and improving its behavior along fermentation. However, current models for L. plantarum are applicable to only one substrate. The growth of a newly isolated strain L. plantarum 60-1 in a co-substrate (glucose and lactose) and lactic acid production in the batch process, were modeled in this work. Biomass growth was well described bydouble Monod kinetics. Substrate consumptions were modeled using two balance equations. Lactic acid was described with the Luedeking–Piret equation. No product inhibition was observed. Both glucose and lactose were metabolized in a concomitant way. This is the first report (as we know it) of a model includes dynamics of a dual limitation substrate glucoseand lactose in multiplicative effects on the growth of L. plantarum 60-1
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Wang, Xia, Ping Xu, Yong Yuan, et al. "Modeling for Gellan Gum Production by Sphingomonas paucimobilis ATCC 31461 in a Simplified Medium." Applied and Environmental Microbiology 72, no. 5 (2006): 3367–74. http://dx.doi.org/10.1128/aem.72.5.3367-3374.2006.
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ABSTRACT Gellan gum production was carried out by Sphingomonas paucimobilis ATCC 31461 in a simplified medium with a short incubation time, and a kinetic model for understanding, controlling, and optimizing the fermentation process was proposed. The results revealed that glucose was the best carbon source and that the optimal concentration was 30 g liter−1. As for the fermenting parameters, considerably large amounts of gellan gum were yielded by an 8-h-old culture and a 4% inoculum at 200 rpm on a rotary shaker. Under the optimized conditions, the maximum level of gellan gum (14.75 g liter−1) and the highest conversion efficiency (49.17%) were obtained in a 30-liter fermentor in batch fermentation. Logistic and Luedeking-Piret models were confirmed to provide a good description of gellan gum fermentation, which gave some support for the study of gellan gum fermentation kinetics. Additionally, this study is the first demonstration that gellan gum production is largely growth associated by analysis of kinetics in its batch fermentation process. Based on model prediction, higher gellan gum production (17.71 g liter−1) and higher conversion efficiency (57.12%) were obtained in fed-batch fermentation at the same total glucose concentration (30 g liter−1).
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Kondybayev, Askar, Gaukhar Konuspayeva, Caroline Strub, et al. "Growth and Metabolism of Lacticaseibacillus casei and Lactobacillus kefiri Isolated from Qymyz, a Traditional Fermented Central Asian Beverage." Fermentation 8, no. 8 (2022): 367. http://dx.doi.org/10.3390/fermentation8080367.
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The growth characteristics of two strains of lactic acid bacteria (LAB), Lacticaseibacillus casei and Lactobacillus kefiri, isolated from qymyz, a traditional fermented mare milk beverage, were studied and modeled, including the effect of different carbohydrates, pH, and temperature. Along with population, substrates, and metabolites, lactic acid and ethanol were monitored by HPLC. Growth parameters were obtained from mono- and biphasic logistic growth models that fit the population evolution of L. casei and L. kefiri, respectively. The effect of temperature and pH on the growth rate was represented with the gamma concept model, while the effect of the limiting substrate was evaluated according to the Monod equation. Lastly, a simplified Luedeking and Piret equation was used to represent metabolite production. The optimum values of pH and temperature were 6.69 ± 0.20, 38.63 ± 0.32 °C, 5.93 ± 0.08, and 33.15 ± 0.53 °C, with growth rate values of 0.66 ± 0.01 h−1 and 0.29 ± 0.01 h−1 for L. casei and L. kefiri, respectively. L. casei had a homofermentative pathway, while L. kefiri was heterofermentative, with an ethanol production rate of 2.90 × 10−9 mg·CFU−1. The Monod model showed that L. casei had the lowest Ks value for lactose, while for L. kefiri, it was the highest among milk carbohydrates. These results show that the population of the two LAB strains and therefore the concentrations of acid and ethanol can be controlled by the fermentation conditions and that our model can help to significantly improve the production of qymyz.
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Mardawati, Efri, Andi Trirakhmadi, MTAP Kresnowati, and Tjandra Setiadi. "Kinetic study on Fermentation of xylose for The Xylitol Production." Journal of Industrial and Information Technology in Agriculture 1, no. 1 (2017): 1. http://dx.doi.org/10.24198/jiita.v1i1.12214.
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Xylitol is a natural sugar that has the sweetness level similar to sucrose, but has lower calorie. It is an important sugar alternate for diabetics people. Reduction of xylose is a normally method to produce the xylitol. It Conducted via chemical hydrogenation of xylose at high pressures and temperatures by reacting pure xylose with hydrogen gas using a metal catalyst. This process requires pure xylose as the raw material. Alternatively, the reduction process can be carried out via fermentation. This process does not require high purity of xylose as the raw material, and thus the oil palm empty fruit bunch (EFB) hydrolysate, without any prior pretreatment, can be used. In order to scale up the xylitol production via fermentation, kinetic study of xylitol fermentation including growth and xylitol formation kinetic using the synthetic xylose as substrate will be required. Data used in the kinetic model development were obtained from series of batch fermentations of Debaryomycess hansenii ITB CCR85 varying the initial xylose and glucose concentrations. Yeast growth could be sufficiently modeled using the Monod kinetics, whereas xylitol production could be reasonably well modelled by Luedeking Piret kinetics.
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Shahriarinour, Mahdi, Mohd Noor Abdul Wahab, Arbakariya B. Ariff, Shuhaimi Mustafa, and Rosfarizan Mohamad. "Kinetics of cellulase production by Aspergillus terreus at various levels of dissolved oxygen tension in a stirred tank bioreactor." BioResources 6, no. 4 (2011): 4909–21. http://dx.doi.org/10.15376/biores.6.4.4909-4921.
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In this study the effect of different levels of dissolved oxygen tension (d.o.t) on the production of three main components of extracellular cellulases (FPase, CMCase and β-glucosidase) at a fixed agitation speed by Aspergillus terreus was investigated. Growth of A. terreus and cellulase production were modeled based on logistic and Luedeking-Piret equations. The results from the model fit well with the experimental data, confirming that the models were appropriate for describing and representing growth and cellulase production at various d.o.t levels. The models showed that the production of FPase and CMCase were growth-associated processes. Cell growth and cellulase production were approximately two-fold higher in a stirred tank bioreactor compared with a shake-flask culture. At a d.o.t of 55% air saturation, cell growth and cellulase production were higher than at low d.o.t (40% air saturation) or high d.o.t (80% air saturation). The highest activities of FPase (2.33 U ml-1), CMCase (51.10 U ml-1), and β-glucosidase (16.18 U ml-1) were obtained at a d.o.t of 55% air saturation, yielding overall productivities of 19.40, 425.00, and 67.40 U l.h-1, respectively.
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Groff, María Carla, Sandra Edith Noriega, Rocío Mariel Gil, Nadia Pantano, and Gustavo Scaglia. "Dynamic Optimization of Lactic Acid Production from Grape Stalk Solid-State Fermentation with Rhizopus oryzae Applying a Variable Temperature Profile." Fermentation 10, no. 2 (2024): 101. http://dx.doi.org/10.3390/fermentation10020101.
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Lactic acid is widely used in the food industry. It can be produced via chemical synthesis or biotechnological pathways by using renewable resources as substrates. The main challenge of sustainable production lies in reaching productivities and yields that allow for their industrial production. In this case, the application of process engineering becomes a crucial tool to improve the performance of bioprocesses. In this work, we performed the solid-state fermentation of grape stalk using Rhizopus oryzae NCIM 1299 to obtain lactic acid, employing three different temperatures (22, 35, and 40 °C) and a relative humidity of 50%. The Logistic and First-Order Plus Dead Time models were adjusted for fungal biomass growth, and the Luedeking and Piret with Delay Time model was used for lactic acid production, obtaining higher R2 values in all cases. At 40 °C, it was observed that Rhizopus oryzae grew in pellet form, resulting in an increase in lactic acid productivity. In this context, the effect of temperature on the kinetic parameters was evaluated with a polynomial correlation. Finally, using this correlation, a smooth and continuous optimal temperature profile was obtained by a dynamic optimization method, improving the final lactic acid concentration by 53%.
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Rajendran, Aravindan, and Viruthagiri Thangavelu. "Optimization of medium composition for lipase production by Candida rugosa NCIM 3462 using response surface methodology." Canadian Journal of Microbiology 53, no. 5 (2007): 643–55. http://dx.doi.org/10.1139/w07-017.
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A sequential optimization approach using statistical design of experiments was employed to enhance the lipase production by Candida rugosa in submerged batch fermentation. Twelve medium components were evaluated initially using the Plackett–Burman 2-level factorial design. The significant variables affecting lipase production were found to be glucose, olive oil, peptone, (NH4)2SO4, and FeCl3·6H2O. Various vegetable oils were tested in the second step, and among them, groundnut oil was found to be the best inducer for lipase production by C. rugosa. The third step was to identify the optimal values of the significant medium components with groundnut oil as the inducer using response surface methodology. The regression equation obtained from the experimental data designed using a central composite design was solved, and analyzing the response surface contour plots, the optimal concentrations of the significant variables were determined. A maximum lipase activity of 5.95 U·mL–1, which is 1.64 times the maximum activity obtained in the Plackett–Burman experimental trials, was observed. The optimum combination of medium constituents contained 19.604 g·L–1 glucose, 13.065 mL·L–1 groundnut oil, 7.473 g·L–1 peptone, 0.962 g·L–1 (NH4)2SO4, 0.0019 g·L–1 FeCl3·6H2O, and other insignificant components at the fixed level. A predictive model of the combined effects of the independent variables using response surface methodology and an artificial neural network was proposed. The unstructured kinetic models, logistic model, and Luedeking–Piret model were used to describe cell mass and lipase production. The parameters of the models were evaluated and the lipase production by C. rugosa was found to be growth associated.
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Colucci Cante, Rosa, Marianna Gallo, Federica Nigro, Francesca Passannanti, Andrea Budelli, and Roberto Nigro. "Mathematical Modeling of Lactobacillus paracasei CBA L74 Growth during Rice Flour Fermentation Performed with and without pH Control." Applied Sciences 11, no. 7 (2021): 2921. http://dx.doi.org/10.3390/app11072921.
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The mathematical modeling of fermentation processes allows for the formulation of predictions about the kinetics of biomass growth and metabolite production as well as setting or verifying the best operative conditions in view of the economical convenience of the process. For this purpose, we performed a kinetic study of a rice flour fermentation process using Lactobacillus paracasei CBA L74 with and without pH control; the pH value was set to 5.8 under pH control. Monod, Logistic, and Contois models were proposed to describe the bacterial growth rate in both conditions. The best mathematical model, which was able to describe the experimental data obtained without pH control, was the Contois model, as the specific growth rate was influenced by both the glucose reduction (from 14.31 g/L to 10.22 g/L) and the biomass production (2 log growth) that occurred during fermentation. Conversely, when pH control was implemented, both Monod and Contois models satisfactorily described the specific growth rate trend. The estimated kinetic parameters confirmed that biomass production (2 log growth) and glucose consumption (from 14.31 g/L to 6.06 g/L) did not affect the microorganism’s growth capacity when the fermenting medium was maintained at an optimal pH. The lactic acid production rate described by the Luedeking–Piret model did not appear to be linked to growth in the absence of pH control while, on the other hand, this model was unsuitable for describing the experimental lactic acid concentration when pH control was applied. The kinetic modeling of lactic acid production and the percentage of added glucose in the protocol with controlled pH will be optimized in the future.
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Salazar, Yolocuauhtli, Paul A. Valle, Emmanuel Rodríguez, Nicolás O. Soto-Cruz, Jesús B. Páez-Lerma, and Francisco J. Reyes-Sánchez. "Mechanistic Modelling of Biomass Growth, Glucose Consumption and Ethanol Production by Kluyveromyces marxianus in Batch Fermentation." Entropy 25, no. 3 (2023): 497. http://dx.doi.org/10.3390/e25030497.
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This paper presents results concerning mechanistic modeling to describe the dynamics and interactions between biomass growth, glucose consumption and ethanol production in batch culture fermentation by Kluyveromyces marxianus (K. marxianus). The mathematical model was formulated based on the biological assumptions underlying each variable and is given by a set of three coupled nonlinear first-order Ordinary Differential Equations. The model has ten parameters, and their values were fitted from the experimental data of 17 K. marxianus strains by means of a computational algorithm design in Matlab. The latter allowed us to determine that seven of these parameters share the same value among all the strains, while three parameters concerning biomass maximum growth rate, and ethanol production due to biomass and glucose had specific values for each strain. These values are presented with their corresponding standard error and 95% confidence interval. The goodness of fit of our system was evaluated both qualitatively by in silico experimentation and quantitative by means of the coefficient of determination and the Akaike Information Criterion. Results regarding the fitting capabilities were compared with the classic model given by the logistic, Pirt, and Luedeking–Piret Equations. Further, nonlinear theories were applied to investigate local and global dynamics of the system, the Localization of Compact Invariant Sets Method was applied to determine the so-called localizing domain, i.e., lower and upper bounds for each variable; whilst Lyapunov’s stability theories allowed to establish sufficient conditions to ensure asymptotic stability in the nonnegative octant, i.e., R+,03. Finally, the predictive ability of our mechanistic model was explored through several numerical simulations with expected results according to microbiology literature on batch fermentation.
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Naydenova, Greta, Petya Popova-Krumova, Svetla Danova, and Dragomir Yankov. "Lactic Acid Production from Distiller’s Dried Grains Dilute Acid Hydrolysates." Fermentation 10, no. 11 (2024): 581. http://dx.doi.org/10.3390/fermentation10110581.
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Lactic acid (LA) is an important chemical with diverse applications in various industries. LA can be produced by the fermentation of different substrates by many microorganisms such as bacteria, fungi, yeasts, and algae. Lactic acid bacteria (LAB) are generally accepted as the main producers of LA. A distinct characteristic of LAB is the complexity of the fermentation media. Distiller’s dried grains with solubles (DDGS), a by-product from bioethanol production, represent a promising substitute for costly sugars in the nutrition media for LA production. In the present paper, the possibility of using dilute acid DDGS hydrolysates as a substrate for LA fermentation was investigated. The influence of different factors (acid concentration, time, pressure, solid-to-liquid ratio) on the reducing sugars (RS) obtained was studied. Additional enzyme hydrolysis was carried out to increase RS content in the hydrolysates. LA production from hydrolysates without and with control of the pH during fermentation was monitored and compared with lactose as a substrate. Inhibition of the process was observed in both substrates in the absence of pH control which was overcome in the case of pH control. A mathematical model based on the Verhulst and Ludeking–Piret equations was proposed and tested, showing very good agreement with experimental data.
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Ruarte, Pablo Javier, Maria Jose Leiva Alaniz, Silvia Cristina Vergara, et al. "Mathematical Modeling for Fermentation Systems: A Case Study in Probiotic Beer Production." Fermentation 11, no. 4 (2025): 184. https://doi.org/10.3390/fermentation11040184.
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The use of autochthonous yeast strains from viticultural environments represents a novel approach in the brewing industry. Probiotic-fermented beers have generated growing interest as they combine traditional brewing with the increasing demand for health-oriented functional beverages. The application of mathematical modeling to fermentation kinetics becomes a crucial tool to adequately describe and subsequently improve the performance of functional beer fermentation. The Saccharomyces cerevisiae PB101 autochthonous yeast from San Juan (Argentina) was previously selected for its probiotic potential and its exceptional technological traits in beer wort production. It was subsequently used to ferment a Kölsch-style brewer’s wort in order to evaluate both its probiotic potential and its resistance to the human digestive system. The results showed a survival percentage of 73.49 ± 0.54 and 80.17 ± 3.73 in fermentations conducted in 2024 and 2025, respectively. These fermentation assays were used to explore kinetic microbial growth, ethanol production, and critical fermentation parameters. Traditional modeling approaches often fail to adequately capture the intricacies of probiotic fermentations, particularly lag phases associated with microbial adaptation and metabolite biosynthesis. To address these limitations, this study develops an innovative and simple modeling system for modeling probiotic beer fermentation by incorporating two state variables: total and dead cells. The dynamics of these two variables were modeled using either a First Order Plus Dead Time model or a logistic growth model. Furthermore, the modified Luedeking–Piret model was used to study the delay time that exists between the production of viable cells and ethanol. The proposed models demonstrate enhanced predictive accuracy and dependability, providing a solid foundation for optimizing fermentation processes and advancing the development of functional beverages with exceptional probiotic properties.
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Groff, María Carla, Sandra Edith Noriega, María Eugenia Díaz Meglioli, Laura Rodríguez, Benjamín Kuchen, and Gustavo Scaglia. "Determination of Variable Humidity Profile for Lactic Acid Maximization in Fungal Solid-State Fermentation." Fermentation 10, no. 8 (2024): 406. http://dx.doi.org/10.3390/fermentation10080406.
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Solid-state fermentation (SSF) is the bioprocess where microorganisms are cultivated in the absence of free water under controlled conditions. Lactic acid can be produced by Rhizopus oryzae SSF of grape stalks. During the microorganism’s growth, the temperature and water content of the solid bed fluctuate, leading to areas of either dry or excessive moisture in the solid substrate. Therefore, it is crucial to control the water supply to the matrix. In this work, we obtain lactic acid through SSF of grape stalks using Rhizopus oryzae NCIM 1299. The SSF was conducted at a fixed temperature of 35 °C, with five constant relative humidity (RH) levels: 50, 57, 65, 72, and 80%RH. Mathematical models, including the Logistic and First-Order Plus Dead-Time models for fungal biomass growth and the Luedeking and Piret with Delay Time model for lactic acid production, were adjusted to kinetic curves. Growth kinetic parameters (Xmax, μmax, Tp, T0, Yp/x, and td) were determined for all conditions. These kinetic parameters were then correlated with relative humidity using a second-degree polynomial relationship. We observed a decrease in Xmax with an increasing %RH, while the value of Yp/x increased at a higher %RH. Finally, the optimal variable relative humidity profile was obtained by applying the dynamic optimization technique, resulting in a 16.63% increase in lactic acid production.
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Jayaraman, Jayamuthunagai, and Pennathur Gautam. "Evaluation of production and kinetics parameters of rare sugar (D-tagatose) using biocatalyst Arthrobacter globiformis." Management of Environmental Quality: An International Journal 27, no. 1 (2016): 71–78. http://dx.doi.org/10.1108/meq-07-2015-0124.
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Purpose – Dulcitol (Galactitol) is a sugar alcohol which is produced by redox reaction of galactose. It has been reported that the D-tagatose can be produced from dulcitol (D-galactitol) via the oxidation reaction by the acetic acid bacteria such as Arthobacter globiformis, Gluconobacter oxydans. The D-tagatose sugar is a ketohexose monosaccharide sweetener, which is an isomer of D-galactose. D-tagatose is rarely found in nature and it can be utilized in many ways particular in prebiotic property. The purpose of this paper is to speak about the production and kinetics of D-tagatose from dulcitol using a wild strain of Arthobacter globiformis MTCC 944. Design/methodology/approach – The wild strain Arthobacter globiformis was procured from Microbial Type Culture Collection, Chandigarh and was grown in slants (Dulcitol of 2 percent (w/v)) by sub culturing for every two weeks until transferred to production medium containing 10 percent (w/v) of dulcitol operating aerobically at 25°C and 180 rpm. Biomass estimation was carried out taking samples periodically and measuring its OD value using spectronic-20D spectrophotometer at 600 nm. Kinetics of biomass was determined using Logistic growth kinetic model and that of D-tagatose production was estimated using Leudking-Piret model. Findings – The maximum production of D-tagatose (3.82 g/L) was obtained at the initial dulcitol concentration of 20 g/L and at a pH of 6.0 and temperature of 25°C. Effect of inoculum size on the fermentation of D-tagatose was studied. Threefold increases in yield of tagatose was achieved at the higher inoculum concentration of 24 percent v/v. Originality/value – The strain Arthrobacter globiformis, selected for the production of D-tagatose is not much investigated strain. Dulcitol, the substrate chosen for the study is less expensive when compare with galactose which is largely used by the investigators.
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Deseure, Jonathan, Jamila Obeid, John C. Willison, and Jean-Pierre Magnin. "Reliable determination of the growth and hydrogen production parameters of the photosynthetic bacterium Rhodobacter capsulatus in fed batch culture using a combination of the Gompertz function and the Luedeking-Piret model." Heliyon 7, no. 7 (2021): e07394. http://dx.doi.org/10.1016/j.heliyon.2021.e07394.
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Sawsan, Mahmood, Ali Ali, Darwesh Ayhem, and Zam Wissam. "Optimization of baker`s yeast production on grape juice using response surface methodology." Acta Periodica Technologica, no. 52 (2021): 89–110. http://dx.doi.org/10.2298/apt2152089s.
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There is an increasing interest in improving biological processes, including fermentation processes, improving fermentation conditions is difficult, as it requires the use of an appropriate improvement method that allows operating the biological fermenter under optimal conditions in order to obtain the largest possible amount of the final product. The aim of this work was to succeed in examples of fermentation conditions to produce the largest possible quantity of dry yeast biomass Saccharomyces cerevisiae using grape juice as the sole carbon source. The optimum values of five factors that have an effect on the production of dry biomass from baker`s yeast were determined. The design of the experiments was carried out using the central composite experimental design (CCD) and the number of experiments according to the design was (54) experiments, the response surface methodology method was used to determine the best possible amount of production of yeast, and has reached (41.44 g/L) after 12 hours of fermentation, under the following optimal conditions (temperature (30.11??), pH (4.75), sugar concentration (158.36 g/L), the ratio of carbon to nitrogen (an essential nutrient for yeast growth ) is (11.9), initial concentration of yeasts (2.5 g/L), the amount of urea was 6.65 g/L and the amount of ammonium sulfate used was 6.65 g/L, so that the concentration of added urea and ammonium sulfate was (50-50)% and the required C/N ratio was achieved, and the used agitation speed was equal to 200 r.p.m during the fermentation process. The fermenter power of the obtained yeast was 470 ml. Three kinematic models (Monod, Verhulst, and Tessier) were also selected for the purpose of studying the kinetic performance of Saccharomyces cerevisiae yeast. Monod and Tessier`s models did not give satisfactory results, while the best results were according to the Verhulst model. Also, the Leudeking Piret model has also been successfully used to predict substrate consumption during fermentation time.
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Komalasari, Yuli, Imam Sutoyo, and Surtika Ayumida. "Perancangan Sistem Informasi Perekaman Presensi Dan Absensi Siswa Menggunakan Model RAD." Jurnal Infortech 5, no. 1 (2023): 58–63. http://dx.doi.org/10.31294/infortech.v5i1.15779.
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Kegiatan perekaman presensi dan absensi siswa yang biasanya dilaksanakan oleh guru atau petugas piket merupakan kegiatan vital dari operasional sebuah sekolah dalam rangka mendisiplinkan siswa. Oleh karena itu, kegiatan ini perlu ditingkatkan efektifitas dan efisiensinya. Salah satu permasalahan yang menghambat kinerja petugas piket adalah pemrosesan data dan informasi secara manual dikarenakan belum adanya sistem yang terkomputerisasi. Penelitian ini bertujuan untuk merancang sistem informasi perekaman presensi dan absensi yang nantinya dapat dibangun menjadi sebuah Minimum Viable Product (MVP) yang akan menggantikan seluruh prosedur manual sehingga kinerja petugas piket dapat ditingkatkan efektifitas dan efisiensinya. Untuk perancangannya digunakan Unified Modelling Language (UML) dan Entity Relationship Diagram (ERD), sedangkan metode pengembangan sistem yang digunakan adalah model RAD (Rapid Application Development).
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Yu, Wen‐Der. "PIREM: a new model for conceptual cost estimation." Construction Management and Economics 24, no. 3 (2006): 259–70. http://dx.doi.org/10.1080/01446190500183735.
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Zhang, Pin, Zhen-Yu Yin, and Brian Sheil. "si-PiNet: A novel stress integration method for elastoplastic models." Géotechnique Letters 15, no. 1 (2025): 1–22. https://doi.org/10.1680/jgele.24.00043.
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Elastoplastic theory is ubiquitous in engineering for modelling the mechanical behaviours of various materials such as metals and granular matter. Elastoplasticity allows computation of plastic strains and updated stresses with hardening parameters using explicit and/or implicit integration algorithms, requiring strong mathematical and domain knowledge. This study proposes a novel stress integration prior information based neural network (si-PiNet) to achieve step-change improvements in the solution of elastoplastic stress-strain responses. si-PiNet leverages a strong non-linear mapping ability in high-dimensional space to search for the correct stress under a given strain increment. The associated stress prediction is constrained by encoded prior information in the form of elastoplastic theory. To verify feasibility and generalization, si-PiNet is applied to solve three canonical elastoplastic constitutive models, namely von Mises, Mohr-Coulomb and Modified Cam-clay. The results indicate si-PiNet can accurately capture the evolution of stress and hardening of various complex constitutive models, whilst also achieving a lower sensitivity to the magnitude of strain increment compared with conventional stress integration algorithms. si-PiNet provides engineering researchers with a new generic paradigm for the computation of plastic strain and updating of stresses with potential for application to any constitutive model of interest.
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Rawlins, Matthew, Vesa Cheng, Edward Raby, et al. "Pharmacokinetics of Ceftolozane-Tazobactam during Prolonged Intermittent Renal Replacement Therapy." Chemotherapy 63, no. 4 (2018): 203–6. http://dx.doi.org/10.1159/000493196.
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Background: Prolonged intermittent renal replacement therapy (PIRRT) eliminates many drugs, and without dosing data, for new antibiotics like ceftolozane/tazobactam, suboptimal concentrations and treatment failure are likely. Objectives: Herein, we describe the effect of PIRRT on the plasma pharmacokinetics of ceftolozane/tazobactam administered in a critically ill 55-year-old patient with a polymicrobial sternal wound osteomyelitis, including a multiresistant Pseudomonas aeruginosa. Method: Blood samples were taken over 4 days where the patient received a 7.5-h PIRRT treatment. One- and 2-compartment models were tested for ceftolozane and tazobactam separately, and the log-likelihood ratio and goodness-of-fit plots were used to select the final model. Results: Two-compartment models were developed for ceftolozane and tazobactam separately and described significant differences in clearance of ceftolozane and tazobactam with and without PIRRT (8.273 vs. 0.393 and 8.020 vs. 0.767 L/h, respectively). Conclusions: A ceftolozane/tazobactam dose of 500 mg/250 mg appears to be sufficient to attain pharmacokinetic/pharmacodynamic targets during PIRRT while the manufacturer’s recommended dosing of 100 mg/50 mg every 8 h was sufficient during non-PIRRT periods.
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Dong, Huan Huan, Li He, and Hong Wei Lu. "The Effects of Noises in the Marr-Pirt Model." Applied Mechanics and Materials 615 (August 2014): 282–85. http://dx.doi.org/10.4028/www.scientific.net/amm.615.282.
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This study aims to analyze the effect of Marr-Pirt model driven by white and integrated noises. The Gaussian white noise and integrated noises are generated using the Box-Muller algorithm. It is observed that noises could change the peak value and time of the model. In addition, integrated noises have more significant impact on the model than white noise when they are under the same intensity. This reveals integrated noises can better approximate to a practical stochastic process, and deserve substantial attention.