Journal articles: 'Bacteria. Flocculation'

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Ugbenyen, Anthony M., John J. Simonis, and Albertus K. Basson. "Screening for Bioflocculant-Producing Bacteria from the Marine Environment of Sodwana Bay, South Africa." Annals of Science and Technology 3, no. 1 (June 1, 2018): 16–20. http://dx.doi.org/10.2478/ast-2018-0010.

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AbstractFlocculants are chemicals that mediate flocculation process, by aggregating colloids from suspension to form floc. Chemical flocculants are hazardous to the environment, which inform the search for safer and eco-friendly alternatives from microorganisms. Bacterial strains were isolated from water and sediment samples collected from Sodwana Bay, South Africa, and physiological properties of the bacterial strains were observed. Flocculation test using kaolin clay suspension was done on all isolates and the ones that showed flocculating activity were identified molecularly using 16 rRNA gene sequence analysis. Forty marine bacteria isolates were gotten from sediments and water samples collected from Sodwana Bay. Most of the isolates exhibited a range of colony pigmentation (pink, creamy, yellow, and white). After purification of individual isolates, they were screened for their potential to produce bioflocculant. The result revealed that isolates marked SOD3, SOD10, SOD12, SOD26, SOD27, SOD28, SOD32, SOD33 and SOD34 produced bioflocculants as shown by the flocculating activities from their crude extract. All these isolates showed good flocculation of kaolin clay suspension above 60% (flocculating activity) except SOD12. These bioflocculant producing isolates were identified asPseudoalteromonas sp,Alcaligenes faecalis,Bacillus subtilis,Bacillus cereus,Bacillus stratosphericus. The results showed Sodwana Bay, South Africa as a reservoir of bacteria with potential to produce flocculants. However, further studies on the optimisation of culture conditions for bioflocculant production, extraction, characterisation and application of isolates is on the way to underscore the biotechnological importance of these microbes as producers of substitutes to harmful chemical flocculants commonly used in water and wastewater treatment.

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Wang, Xin Xin, Liang Wu, Ping Zhou, Chen Li, Li Bin Zhao, Wei An, and Yu Chen. "Harvesting of Polycyclic Aromatic Hydrocarbons (PAHs)-Degrading Bacteria by Magnetic Flocculation." Applied Mechanics and Materials 665 (October 2014): 563–66. http://dx.doi.org/10.4028/www.scientific.net/amm.665.563.

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Magnetic flocculation was reported to be efficient to harvest microalgae. However, little is known about the recovery of PAHs-degrading bacteria from the culture by magnetic flocculation.Advenella kashmirensisstrain w13003, a PAHs-degrading bacterium, was harvested by magnetic flocculation using magnetite and polyferric sulphate (PFS) as flocculants. The results showed the treatment with magnetite and PFS showed high concentration factor with flocculation efficiency near 100%, which suggest magnetic flocculation could result in a high concentration factor without significantly loss of PAHs-degrading bacteria. This is the first report about the recovery of PAHs-degrading bacteria by magnetic flocculation, which suggest its potential in bacterial harvesting.

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Prombutara, P., and M. S. Allen. "Flocculation-Related Gene Identification by Whole-Genome Sequencing of Thauera aminoaromatica MZ1T Floc-Defective Mutants." Applied and Environmental Microbiology 82, no. 6 (December 28, 2015): 1646–52. http://dx.doi.org/10.1128/aem.02917-15.

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ABSTRACTThauera aminoaromaticaMZ1T, a floc-forming bacterium isolated from an industrial activated-sludge wastewater treatment plant, overproduces exopolysaccharide (EPS), leading to viscous bulking. This phenomenon results in poor sludge settling and dewatering during the clarification process. To identify genes responsible for bacterial flocculation, a whole-genome phenotypic-sequencing technique was applied. Genomic DNA of MZ1T flocculation-deficient mutants was subjected to massively parallel sequencing. The resultant high-quality reads were assembled and compared to the reference genome of the wild type (WT). We identified nine nonsynonymous mutations and one nonsense mutation putatively involved in EPS biosynthesis. Complementation of the nonsense mutation located in an EPS deacetylase gene restored the flocculating phenotype. The Fourier transform infrared (FTIR) spectra of EPS isolated from the wild type showed a reduced C=O peak of theN-acetyl group at 1,665 cm−1compared to the spectra of MZ1T floc-deficient mutant EPS, suggesting that the WT EPS was partially deacetylated. Gene expression analysis also demonstrated that the putative deacetylase gene transcript increased before flocculation occurred. These data suggest that targeting deacetylation processes via direct chemical modification of EPS or enzyme inhibition may prove useful in combating viscous bulking in this and related bacteria.

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Okano, Chigusa, Koki Chiba, Eri Nasuno, Ken-ichi Iimura, and Norihiro Kato. "Complex Flocculation of Biofilm-forming Bacteria in the Presence of Flocculating Bacteria Isolated from Activated Sludge." Transactions of the Materials Research Society of Japan 42, no. 3 (2017): 77–80. http://dx.doi.org/10.14723/tmrsj.42.77.

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Yang, Ming Yan, Feng Han, Jia Tian, Chao Sun, Xia Cui, and Mei Rong Han. "Screening of a Microbial Flocculant Producing Silicate Bacteria MT5-2 and its Flocculating Activity." Advanced Materials Research 599 (November 2012): 3–8. http://dx.doi.org/10.4028/www.scientific.net/amr.599.3.

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A microbial flocculant (MBF) producing silicate bacteria MT5-2 was isolated from different sources of samples by silicate selected medium. Its chemical composition, optimal flocculation conditions，flocculation characteristics and primary application were studied in this paper. The results showed that the flocculant was an extracellular polysaccharide, and its flocculation activity was mainly distributed in the fermentation broth. The optimal flocculation conditions were as follows: for the 100 mL kaolin suspension, flocculant dosage was 4mL, metal cation dosage was 1% of ZnCl2 3mL, pH 7.5. The flocculation activity can reach 95% under this condition. Application results showed that flocculant MT5-2 had better flocculation activity in several common suspensions, such as kieselguhr, bentonite, soil, active carbon and starch, compared with polyacrylamide and inorganic salt.

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Ogunlaja, A., B. J. Ibidunni, K. Oyende, and O. O. Ogunlaja. "Optimization of bioflocculant production by bacteria isolated from oil-polluted soil and fermented maize effluent." Ife Journal of Science 22, no. 2 (August 24, 2020): 201–10. http://dx.doi.org/10.4314/ijs.v22i2.18.

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This study involved isolation of bioflocculant producing bacteria from soil and waste water. The isolates were tested for flocculation activities and those deemed fit were identified and the optimal environmental conditions for bioflocculant production were also determined. Samples were collected from oil-contaminated soil in Redeemer's University and fermented maize waste water. Microbial isolation was done using standardmicrobiological methods and identification was done using morphology, biochemical and molecular method with universal primer for 16SrRNA gene. Environmental conditions (pH, Temperature and cations) and media composition (nitrogen and carbon sources) were altered to optimize bioflocculant production and activities. Percentage flocculating activities were determined and calculated using standard method. We also adjustedrevolution rate and standing time to determine the optimum conditions for flocculation activities. Two bioflocculant producing isolates (Bacillus cereus and Lysinibacillus fusiformis) from oil-polluted soil and two from fermented maize waste water (Bacillus thuringiensis and Bacillus tropicus) were obtained. Neutral pH, temperature o of 30 C and inclusion of CaCl were the best conditions for bioflocculant production in all isolates except for 2 Lysinibacillus fusiformis which was best with acidic pH condition. Maltose as the carbon source was the best for all isolates except Bacillus thuringiensis (fructose) and ammonium was the best nitrogen source for all isolates except Bacillus cereus (peptone). Although condition III showed optimum condition for flocculation activities, the percentage activities were generally lower than normal condition. The highest percentage flocculating activities o of 98% were by Bacillus cereus and Bacillus tropicus at 30 C, neutral pH and 1% (w/v) CaCl salt with soluble starch 2 and maltose as their carbon source respectively. These bacteria can be exploited for their use as flocculants in water treatment. Keywords: Agro-residues; Bio-friendly; Bioflocculant; Contaminated soil; Optimization

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Bello, Antonio Roberto Crystal, Dejanira de Franceschi Angelis, and Roberto Naves Domingos. "Ultrasound efficiency in relation to sodium hypochlorite and filtration adsorption in microbial elimination in a water treatment plant." Brazilian Archives of Biology and Technology 48, no. 5 (September 2005): 739–45. http://dx.doi.org/10.1590/s1516-89132005000600009.

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Processes like ultrasound, chlorination and filtration-adsorption were compared to eliminate microorganisms and to adjust established parameters of public drinking water. A mini water treatment plant (WTP-CB), in pilot scale, was projected and built to evaluate each process influence as: decontamination, coagulation-flocculation, sedimentation and filtration. Total and fecal coliforms, Escherichia coli and heterotrophic bacteria and physic/chemical parameters were quantified from water. Ultrasound, chlorination and filtration-adsorption were efficient to inactivate and/or eliminate bacteria. Ultrasound decontamination in addition to coagulation-flocculation, sedimentation and filtration, could be considered as an alternative treatment water solution where prechlorination, coagulation-flocculation, sedimentation and filtration were used. The chlorination itself was efficient in inactivating bacteria despite of the coagulation-flocculation process; however, in the absence of the coagulation process, the resultant water did not achieve the established parameters. The filtration-adsorption was an important process to eliminate bacteria, showing that the filter retained particles, suspended solids, besides chemical substances and microorganisms.

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Sicchierolli, S. M., E. M. Mamizuka, and A. M. Carmona-Ribeiro. "Bacteria Flocculation and Death by Cationic Vesicles." Langmuir 11, no. 8 (August 1995): 2991–95. http://dx.doi.org/10.1021/la00008a024.

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9

Peng, X., J. Sun, D. Iserentant, C. Michiels, and H. Verachtert. "Flocculation and coflocculation of bacteria by yeasts." Applied Microbiology and Biotechnology 55, no. 6 (June 1, 2001): 777–81. http://dx.doi.org/10.1007/s002530000564.

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Haegeman, Bart, Claude Lobry, and Jérôme Harmand. "Modeling bacteria flocculation as density-dependent growth." AIChE Journal 53, no. 2 (2007): 535–39. http://dx.doi.org/10.1002/aic.11077.

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Abbas, Syed Zaghum, Yang-Chun Yong, Moonis Ali Khan, Masoom Raza Siddiqui, Afnan Ali Hussain Hakami, Shareefa Ahmed Alshareef, Marta Otero, and Mohd Rafatullah. "Bioflocculants Produced by Bacterial Strains Isolated from Palm Oil Mill Effluent for Application in the Removal of Eriochrome Black T Dye from Water." Polymers 12, no. 7 (July 13, 2020): 1545. http://dx.doi.org/10.3390/polym12071545.

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Four strains of bioflocculant-producing bacteria were isolated from a palm oil mill effluent (POME). The four bacterial strains were identified as Pseudomonas alcaliphila (B1), Pseudomonas oleovorans (B2), Pseudomonas chengduensis (B3), and Bacillus nitratireducens (B4) by molecular identification. Among the four bacterial strains, Bacillus nitratireducens (B4) achieved the highest flocculating activity (49.15%) towards kaolin clay suspension after eight hours of cultivation time and was selected for further studies. The optimum conditions for Eriochrome Black T (EBT) flocculation regarding initial pH, type of cation, and B4 dosage were determined to be pH 2, Ca2⁺ cations, and a dosage of 250 mL/L of nutrient broth containing B4. Under these conditions, above 90% of EBT dye removal was attained. Fourier transform infrared spectroscopic (FT-IR) analysis of the bioflocculant revealed the presence of hydroxyl, alkyl, carboxyl, and amino groups. This bioflocculant was demonstrated to possess a good flocculating activity, being a promissory, low-cost, harmless, and environmentally friendly alternative for the treatment of effluents contaminated with dyes.

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Yeo, Y., N. Jang, J. Cho, K. S. Kim, and I. S. Kim. "Identification of the effect of extracellular polymeric substances on bacterial adhesion to the membrane surface in a membrane bioreactor using Pseudomonas fluorescens." Water Science and Technology 55, no. 1-2 (January 1, 2007): 35–42. http://dx.doi.org/10.2166/wst.2007.026.

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In a membrane bioreactor (MBR) process containing a variety of bacteria, the bacterial adhesion to the membrane surface, prior to cake formation, causes an increased filtration resistance. In this study, Pseudomonas fluorescens, commonly found in the municipal wastewater treatment process with activated sludge, was used to show the effects of extracellular polymeric substances (EPS) on bacterial adhesion to the membrane surface in the MBR. Of the various roles of EPS in promoting membrane fouling, the adhesion of bacteria to the membrane surface was calculated using the specific cake resistance (α, m/kg). Although the amount of EPS binding with bacteria was increased by the addition of Ca2 + , there was no significant effect on the bacterial growth. The results of the particle size distribution showed that the addition of Ca2 + increased flocculation, allowing the formation of a complex with the bacteria and EPS. In order to identify the effects of the addition of Ca2 + on the hydrophobicity, the contact angle was also measured. The result showed that the addition of Ca2 + showed no significant differences in the hydrophobicity, even though there was an increase in flocculation. With the bacteria containing a higher EPS concentration, a higher specific cake resistance was observed. From the results of the adhesion experiment, which was conducted with various EPS levels, displayed as the COD and TOC concentration, an increased EPS concentration was shown to promote bacterial adhesion to the membrane surface.

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Touhami, Ahmed, Barbara Hoffmann, Andrea Vasella, Frédéric A. Denis, and Yves F. Dufrêne. "Aggregation of yeast cells: direct measurement of discrete lectin–carbohydrate interactions." Microbiology 149, no. 10 (October 1, 2003): 2873–78. http://dx.doi.org/10.1099/mic.0.26431-0.

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Aggregation of microbial cells mediated by specific interactions plays a pivotal role in the natural environment, in medicine and in biotechnological processes. Here we used atomic force microscopy (AFM) to measure individual lectin–carbohydrate interactions involved in the flocculation of yeast cells, an aggregation event of crucial importance in fermentation technology. AFM probes functionalized with oligoglucose carbohydrates were used to record force-distance curves on living yeast cells at a rate of 0·5 μm s−1. Flocculating cells showed adhesion forces of 121±53 pN, reflecting the specific interaction between individual cell-surface lectins and glucose residues. Similar adhesion forces, 117±41 pN, were measured using probes functionalized with the lectin concanavalin A and attributed to specific binding to cell-surface mannose residues. By contrast, specific interaction forces were not observed in non-flocculating conditions, i.e. in the presence of mannose or when using non-flocculating cells, pointing to their involvement in yeast flocculation. The single molecule force spectroscopy measurements presented here provide a means to study a variety of cellular interactions at the molecular level, such as the adhesion of bacteria to animal and plant tissues.

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Sha'arani, Shazwana, Siti Noor Fitriah Azizan, Fazrena Nadia Md Akhir, Muhamad Ali Muhammad Yuzir, Nor'azizi Othman, Zuriati Zakaria, Megat Johari Megat Mohd Noor, and Hirofumi Hara. "Removal efficiency of Gram-positive and Gram-negative bacteria using a natural coagulant during coagulation, flocculation, and sedimentation processes." Water Science and Technology 80, no. 9 (November 1, 2019): 1787–95. http://dx.doi.org/10.2166/wst.2019.433.

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Abstract Staphylococcus sp. as Gram-positive and Escherichia coli as Gram-negative are bacterial pathogens and can cause primary bloodstream infections and food poisoning. Coagulation, flocculation, and sedimentation processes could be a reliable treatment for bacterial removal because suspended, colloidal, and soluble particles can be removed. Chemical coagulants, such as alum, are commonly used. However, these chemical coagulants are not environmentally friendly. This present study evaluated the effectiveness of coagulation, flocculation, and sedimentation processes for removing Staphylococcus sp. and E. coli using diatomite with standard jar test equipment at different pH values. Staphylococcus sp. demonstrated 85.61% and 77.23% significant removal in diatomite and alum, respectively, at pH 5. At pH 7, the removal efficiency decreased to 79.41% and 64.13% for Staphylococcus sp. and E. coli, respectively. At pH 9, there was a decrease in Staphylococcus sp. after adding diatomite or alum compared with that of E. coli. The different removal efficiencies of the Gram-positive and Gram-negative bacteria could be owing to the membrane composition and different structures in the bacteria. This study indicates that diatomite has higher efficiency in removing bacteria at pH 5 and can be considered as a potential coagulant to replace alum for removing bacteria by the coagulation process.

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Strand, Sabina P., Thomas Nordengen, and Kjetill Østgaard. "Efficiency of chitosans applied for flocculation of different bacteria." Water Research 36, no. 19 (November 2002): 4745–52. http://dx.doi.org/10.1016/s0043-1354(02)00173-2.

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Kfir, R., B. W. Bateman, B. A. Pitout, and P. Coubrough. "Disinfection of Polluted Water by Chlorine-Flocculant Tablet." Water Science and Technology 21, no. 3 (March 1, 1989): 207–13. http://dx.doi.org/10.2166/wst.1989.0101.

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Two water treatment tablets were evaluated for their efficacy of removal of E. coli bacteria, coliphage V1 and polio 1 from water. The activity of both tablets is based on flocculation as well as disinfection with additional straining. The tablets differ from each other only in their disinfectant source, i.e. Chlor-floc A contains Halazone and Chlorfloc B contains dichloro-S-triazine-trione. Tests were carried out using simulated hard and coloured water at room temperature. Results indicated both tablets to be efficient but showed tablet B to be of superior quality. Tablet B was shown to eliminate all bacteria and viruses from the test water after 4 minutes at room temperature (22 °C). Studies on partial removal of the test organisms by filtration or flocculation without chlorination showed that both steps partially removed the organisms, but the combined process of flocculation chlorination followed by filtration proved to be the most effective treatment.

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Biswas, Jayanta Kumar, Anurupa Banerjee, Binoy Sarkar, Dibyendu Sarkar, Santosh Kumar Sarkar, Mahendra Rai, and Meththika Vithanage. "Exploration of an Extracellular Polymeric Substance from Earthworm Gut Bacterium (Bacillus licheniformis) for Bioflocculation and Heavy Metal Removal Potential." Applied Sciences 10, no. 1 (January 3, 2020): 349. http://dx.doi.org/10.3390/app10010349.

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The present study shows the potential of an extracellular polymeric substance (EPS) produced by Bacillus licheniformis strain KX657843 isolated from earthworm (Metaphire posthuma) gut in the sorption of Cu(II) and Zn(II) and in flocculation. After harvesting bacterial cells from sucrose supplemented denitrifying culture medium, the EPS was extracted following ethanolic extraction method. The Fourier Transform Infrared Spectroscopy (FTIR) and 1H and 13C Nuclear Magnetic Resonance (NMR) of EPS revealed its functional groups, electronegative constituents, unsaturated carbon, and carbonyl groups. The negatively charged functional groups of carbohydrates and protein moiety of the EPS endowed it with heavy metal binding capacity through electrostatic interactions. The highest flocculation activity (83%) of EPS was observed at 4 mg L−1 and pH 11. The metal sorption by EPS increased with increasing pH. At pH 8, the EPS was able to remove 86 and 81% Cu(II) and Zn(II), respectively, from a 25 mg L−1 metal solution. 94.8% of both the metals at 25 mg L−1 metal solutions were removed by EPS at EPS concentration of 100 mg L−1. From Langmuir isotherm model, the maximum sorption capacities of EPS were calculated to be 58.82 mg g−1 for Cu(II) and 52.45 mg g−1 for Zn(II). The bacterial EPS showed encouraging flocculating and metal sorption properties. The potential to remove Cu(II) and Zn(II) implies that the EPS obtained from the earthworm gut bacteria can be used as an effective agent for environmental remediation of heavy metals and in bioflocculation.

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Hughes, J., D. K. Ramsden, and K. C. Symes. "The flocculation of bacteria using cationic synthetic flocculants and chitosan." Biotechnology Techniques 4, no. 1 (1990): 55–60. http://dx.doi.org/10.1007/bf00156611.

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Joret, J. C., V. Mennecart, C. Robert, B. Compagnon, and P. Cervantes. "Inactivation of indigenous bacteria in water by ozone and chlorine." Water Science and Technology 35, no. 11-12 (June 1, 1997): 81–86. http://dx.doi.org/10.2166/wst.1997.0714.

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The aim of this study was to compare the level of removal and inactivation of indigenous bacteria during drinking water production as evaluated by culture techniques and epifluorescent microscopic counts of metabolically active bacteria (in situ respiring bacteria i.e. able to metabolise CTC: cyano 2,3-ditolyl tetrazolium chloride). Two sets of experiments were designed: a) bacterial counts through a full scale drinking water treatment plant (multibarrier treatment including coagulation-flocculation-settling, sand filtration, ozonation, biological GAC filtration, post-chlorination) and distribution system; b) benchscale disinfection studies in order to re-evaluate the C.t values necessary to inactivate laboratory grown E. coli or indigenous bacteria from water by ozone and chlorine. Main conclusions of this study are: a) significant amounts of in situ respiring bacteria (undetected by the classical culture techniques) are detected in finished water; b) the efficiency of ozone and chlorine recorded by microscopic counts of active bacteria is much less than supposed by classical enumerations of culturable bacteria; c) previous results reported in the literature may have largely overestimated the bactericidal efficiency of disinfectants used for producing drinking water.

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Li, Shao Xiu, Shu Jie Hu, Dong Mei Li, Wei Wei Duan, Wen Qin Xia, and Zhi Jia Zheng. "The Characteristics of Chitosan Applied in Drinking Water Treatment." Advanced Materials Research 233-235 (May 2011): 638–43. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.638.

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Chitosan is a kind of natural, non-toxic and harmless substance. After its amino-group protonizing, it can form a cationic polymer which has excellent coagulation/flocculation properties. The application of chitosan in potable water treatment for the removal of particulates and dissolved organics has been studied extensively in the last decade. In order to further understand the specific property of chitosan applied in drinking water treatment, this paper introduces the effect of molecule weight and deacetylation of chitosan on coagulation/flocculation and coagulation/flocculation mechanism in drinking water treatment, gives an overview of chitosan characteristics of removal of suspend solids, organics and bacteria in water, particularly, describes the relationship between the removal efficiency of above impurities by chitosan and pH, dosage of chitosan.

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Pogue, Amy J., and Kimberley A. Gilbride. "Impact of protozoan grazing on nitrification and the ammonia- and nitrite-oxidizing bacterial communities in activated sludge." Canadian Journal of Microbiology 53, no. 5 (May 2007): 559–71. http://dx.doi.org/10.1139/w07-027.

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In activated sludge, protozoa feed on free-swimming bacteria and suspended particles, inducing flocculation and increasing the turnover rate of nutrients. In this study, the effect of protozoan grazing on nitrification rates under various conditions in municipal activated sludge batch reactors was examined, as was the spatial distribution of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) within the activated sludge. The reactors were monitored for ammonia, nitrite, nitrate, and total nitrogen concentrations, and bacterial numbers in the presence and absence of cycloheximide (a protozoan inhibitor), allylthiourea (an inhibitor of ammonia oxidation), and EDTA (a deflocculating agent). The accumulations of nitrate, nitrite, and ammonia were lower in batches without than with protozoa grazing. Inhibition of ammonia oxidation also decreased the amount of nitrite and nitrate accumulation. Inhibiting protozoan grazing along with ammonia oxidation further decreased the amounts of nitrite and nitrate accumulated. Induction of deflocculation led to high nitrate accumulation, indicating high levels of nitrification; this effect was lessened in the absence of protozoan grazing. Using fluorescent in situ hybridization and confocal laser scanning microscopy, AOB and NOB were found clustered within the floc, and inhibiting the protozoa, inhibiting ammonia oxidation, or inducing flocculation did not appear to lower the number of AOB and NOB present or affect their position within the floc. These results suggest that the AOB and NOB are present but less active in the absence of protozoa.

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Tingirikari, Jagan Mohan Rao, Damini Kothari, and Arun Goyal. "Superior prebiotic and physicochemical properties of novel dextran from Weissella cibaria JAG8 for potential food applications." Food Funct. 5, no. 9 (2014): 2324–30. http://dx.doi.org/10.1039/c4fo00319e.

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The dextran fromWeissella cibariaJAG8 showed good water holding capacity, emulsion, and flocculation activity. Dextran displayed greater thermal stability, resistance to hydrolysis by simulated gastric juice and α-amylase and promoted the growth of probiotic bacteria.

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Charles, Wipa, Goen Ho, and Ralf Cord-Ruwisch. "Anaerobic bioflocculation of wool scouring effluent: the influence of non-ionic surfactant on efficiency." Water Science and Technology 34, no. 11 (December 1, 1996): 1–8. http://dx.doi.org/10.2166/wst.1996.0256.

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Wool scouring effluent (WSE) contains high concentrations of wool grease emulsified by non-ionic surfactants (nonylphenol polyethoxylates – NPEO). The short-term treatment (1-7 days) of this effluent with anaerobic bacteria resulted in partial grease flocculation. However the efficiency of this process varied largely (30% to 80%) with the source of wool scouring effluent used. The concentration of free surfactant, rather than total surfactant, was found to be the likely reason for the variation in efficiency. In order to elucidate the mechanisms of anaerobic biological flocculation a detailed surfactant analysis was performed. This revealed that anaerobic microbes (taken from sludge of a municipal wastewater treatment plant) had an ability to partially degrade NPEO by shortening the hydrophilic ethoxylate chain causing coagulation and subsequent flocculation of wool grease from the liquor.

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Li, Yi, Jingjing Yu, Zhigang Liu, and Tian Ma. "Estimation and modeling of direct rapid sand filtration for total fecal coliform removal from secondary clarifier effluents." Water Science and Technology 65, no. 9 (May 1, 2012): 1615–23. http://dx.doi.org/10.2166/wst.2012.054.

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The filtration of fecal coliform from a secondary clarifier effluent was investigated using direct rapid sand filters as tertiary wastewater treatment on a pilot scale. The effect of the flocculation dose, flow loading rate, and grain size on fecal coliform removal was determined. Direct rapid sand filters can remove 0.6–1.5 log-units of fecal coliform, depending on the loading rate and grain size distribution. Meanwhile, the flocculation dose has little effect on coliform removal, and increasing the loading rate and/or grain size decreases the bacteria removal efficiency. A model was then developed for the removal process. Bacteria elimination and inactivation both in the water phase and the sand bed can be described by first-order kinetics. Removal was successfully simulated at different loading rates and grain size distributions and compared with the data obtained using pilot-scale filters.

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Ben Rebah, Faouzi, Wissem Mnif, and Saifeldin M. Siddeeg. "Microbial Flocculants as an Alternative to Synthetic Polymers for Wastewater Treatment: A Review." Symmetry 10, no. 11 (November 1, 2018): 556. http://dx.doi.org/10.3390/sym10110556.

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Microorganisms such as bacteria, fungi, and microalgae have been used to produce bioflocculants with various structures. These polymers are active substances that are biodegradable, environmentally harmless, and have flocculation characteristics. Most of the developed microbial bioflocculants displayed significant flocculating activity (FA > 70–90%) depending on the strain used and on the operating parameters. These biopolymers have been investigated and successfully used for wastewater depollution in the laboratory. In various cases, selected efficient microbial flocculants could reduce significantly suspended solids (SS), turbidity, chemical oxygen demand (COD), total nitrogen (Nt), dye, and heavy metals, with removal percentages exceeding 90% depending on the bioflocculating materials and on the wastewater characteristics. Moreover, bioflocculants showed acceptable results for sludge conditioning (accepted levels of dry solids, specific resistance to filtration, moisture, etc.) compared to chemicals. This paper explores various bioflocculants produced by numerous microbial strains. Their production procedures and flocculating performance will be included. Furthermore, their efficiency in the depollution of wastewater will be discussed.

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Yang, Qin-Zheng, Bin Zhou, Jin-Wei Liu, Wen-Rui Shen, Xin-Di Jia, Xiao-Jia He, and Hua-Zhang Zhao. "Nitrate removal from water via self-flocculation of genetically engineered bacteria." Chemical Engineering Science 242 (October 2021): 116750. http://dx.doi.org/10.1016/j.ces.2021.116750.

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Nielsen, P. H., T. R. Thomsen, and J. L. Nielsen. "Bacterial composition of activated sludge - importance for floc and sludge properties." Water Science and Technology 49, no. 10 (May 1, 2004): 51–58. http://dx.doi.org/10.2166/wst.2004.0606.

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Activated sludge flocs consist of numerous constituents which, together with other factors, are responsible for floc structure and floc properties. These properties largely determine the sludge properties such as flocculation, settling and dewaterability. In this paper we briefly review the present knowledge about the role of bacteria in relation to floc and sludge properties, and we present a new approach to investigate the identity and function of the bacteria in the activated sludge flocs. The approach includes identification of the important bacteria and a characterization of their physiological and functional properties. It is carried out by use of culture-independent molecular biological methods linked with other methods to study the physiology and function, maintaining a single cell resolution. Using this approach it was found that floc-forming properties differed among the various bacterial groups, e.g. that different microcolony-forming bacteria had very different sensitivities to shear and that some of them deflocculated under anaerobic conditions. In our opinion, the approach to combine identity with functional analysis of the dominant bacteria in activated sludge by in situ methods is a very promising way to investigate correlations between presence of specific bacteria, and floc and sludge properties that are of interest.

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Ugbenyen, A. M., N. Vine, J. J. Simonis, A. K. Basson, and A. I. Okoh. "Characterization of a bioflocculant produced from the consortium of three marine bacteria of the genera Cobetia and Bacillus and its application for wastewater treatment." Journal of Water, Sanitation and Hygiene for Development 5, no. 1 (November 17, 2014): 81–88. http://dx.doi.org/10.2166/washdev.2014.181.

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In this study, we purified and characterized bioflocculant from a mixed culture of three marine bacteria (Cobetia sp. OAUIFE, Bacillus sp. MAYA, and Bacillus sp. Gilbert with accession number JF799092, JF799093, and HQ537128, respectively) isolated from the sediment sample of Algoa Bay South Africa. The bioflocculant from the consortium showed high flocculation of river water, brewery wastewater, and dairy wastewater, with resultant flocculating activities of 96.4%, 93.7%, and 82.2%, respectively. The applicability of the bioflocculant for removing turbidity and reducing chemical oxygen demand (COD) from these real wastewaters was excellent. The bioflocculant turbidity removal efficiency for brewery wastewater was 92%, while its COD reduction efficiency for dairy wastewater was 99%. A scanning electron microscopy (SEM) image of the purified bioflocculant revealed an amorphous morphology, while Fourier transform infra-red (FTIR) analysis also revealed the presence of amino, hydroxyl, and carboxyl functional groups among others, which could be responsible for the high-flocculating activity of the bioflocculant. This environmental-friendly bioflocculant holds promise for application in the field of biotechnology.

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Poorni, S., and K. A. Natarajan. "Biomediated Separation of Kaolinite and Hematite Using Bacillus subtilis." Advanced Materials Research 825 (October 2013): 223–26. http://dx.doi.org/10.4028/www.scientific.net/amr.825.223.

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Bacillus subtilis was used to demonstrate microbially induced selective flocculation to separate kaolinite and hematite. In neutral pH range of 7 - 8, 90 - 95% of hematite was selectively flocculated whereas 80 - 85% of kaolinite was dispersed using hematite - grown cells. Hematite- grown cells exhibited significant adsorption onto hematite than onto kaolinite, compared to unadapted cells. Kaolinite grown Bacillus subtilis secreted significant amounts of mineral specific proteins which conferred surface hydrophobicity whereas hematite-grown cells secreted more polysaccharides rendering hematite hydrophilic. Bacterial extracellular protein (EP) was isolated and the protein profiles of bacteria grown in the absence and presence of minerals were established.

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Li, Tianrui, Jiangjun Hu, and Liandong Zhu. "Self-Flocculation as an Efficient Method to Harvest Microalgae: A Mini-Review." Water 13, no. 18 (September 18, 2021): 2585. http://dx.doi.org/10.3390/w13182585.

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The development of clean and renewable biofuels has been of wide concern on the topic of energy and environmental issues. As a kind of biomass energy with great application prospects, microalgae have many advantages and are used in the fields of environmental protection and biofuels as well as food or feed production for humans and animals. However, the high cost of microalgae harvesting is the main bottleneck of industrial production on a large scale. Self-flocculation is a cost-efficient and promising method for harvesting microalgal biomass. This article briefly describes the current commonly used technology for microalgae harvesting, focusing on the research progress of self-flocculation. This article explores the relative mechanisms and influencing factors of self-flocculation and discusses a proposal for the integration of algae cultivation and harvesting as well as the co-cultivation of algae and bacteria in an effort to provide a reference for microalgae harvesting with high efficiency and low cost.

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Ding, Guoji, Xiaowei Li, Wei Lin, Yuzuru Kimochi, and Ryuichi Sudo. "Enhanced flocculation of two bioflocculation-producing bacteria by secretion of Philodina erythrophthalma." Water Research 112 (April 2017): 208–16. http://dx.doi.org/10.1016/j.watres.2017.01.044.

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NARABU, TAKASHI. "Nematode species are distinguished with the adhesion and flocculation pattern with bacteria." Kagaku To Seibutsu 34, no. 10 (1996): 652–55. http://dx.doi.org/10.1271/kagakutoseibutsu1962.34.652.

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Sun, Xiaohui, Christophe Danumah, Yang Liu, and Yaman Boluk. "Flocculation of bacteria by depletion interactions due to rod-shaped cellulose nanocrystals." Chemical Engineering Journal 198-199 (August 2012): 476–81. http://dx.doi.org/10.1016/j.cej.2012.05.114.

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Bidault, A., F. Clauss, D. Helaine, and C. Balavoine. "Floc agglomeration and structuration by a specific talc mineral composition." Water Science and Technology 36, no. 4 (August 1, 1997): 57–68. http://dx.doi.org/10.2166/wst.1997.0086.

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The quality of the effluent from a waste water treatment plant using the activated sludge process depends upon the bacteria flocculation efficiency. Intensive research work has been devoted to understanding flocculation phenomena and to correct disorders. The addition of very fine but dense talc particles to the aeration tank immediately improves floc formation and densifies the new flocs created. In the longer term, the fine talc particles improve floc structuration and form stable and strong flocs. This has been demonstrated by running a modified activated sludge through the high shear strength of pumps and hydrocyclones. These fine talc particles offer a solution to solve floc settleability problems which so frequently arise when biological disorders appear in waste water treatment plants. Two practical cases are presented.

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Petropoulos, Penny, and Kimberley A. Gilbride. "Nitrification in activated sludge batch reactors is linked to protozoan grazing of the bacterial population." Canadian Journal of Microbiology 51, no. 9 (September 1, 2005): 791–99. http://dx.doi.org/10.1139/w05-069.

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Protozoa feed upon free-swimming bacteria and suspended particles inducing flocculation and increasing the turnover rate of nutrients in complex mixed communities. In this study, the effect of protozoan grazing on nitrification was examined in activated sludge in batch cultures maintained over a 14-day period. A reduction in the protozoan grazing pressure was accomplished by using either a dilution series or the protozoan inhibitor cycloheximide. As the dilutions increased, the nitrification rate showed a decline, suggesting that a reduction in protozoan or bacterial concentration may cause a decrease in nitrification potential. In the presence of cycloheximide, where the bacterial concentration was not altered, the rates of production of ammonia, nitrite, and nitrate all were significantly lower in the absence of active protozoans. These results suggest that a reduction in the number or activity of the protozoans reduces nitrification, possibly by limiting the availability of nutrients for slow-growing ammonia and nitrite oxidizers through excretion products. Furthermore, the ability of protozoans to groom the heterotrophic bacterial population in such systems may also play a role in reducing interspecies competition for nitrification substrates and thereby augment nitrification rates.Key words: nitrification, activated sludge, protozoan grazing, ammonia-oxidizing bacteria, cycloheximide.

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Nazeer, Nauman, Juan Carlos Rodriguez-Lecompte, and Marya Ahmed. "Bacterial-Specific Aggregation and Killing of Immunomodulatory Host Defense Peptides." Pharmaceuticals 14, no. 9 (August 24, 2021): 839. http://dx.doi.org/10.3390/ph14090839.

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This study involves the design and development of disulfide bridge-linked antimicrobial peptides using the host defense protein Angiogenin 4 (chAng4) as a template. The mini peptides derived from chAng4 (mCA4s) were evaluated for their antibacterial efficacies in various pathogenic bacterial strains, and the role of the oxidation state of thiols in the peptide sequence and its implication on antibacterial properties were explored. A remarkable property of these synthetic mCA4 peptides is their capability to flocculate bacteria and mediate bacterial-specific killing, in the absence of any other external stimulus. mCA4s were further evaluated for their cellular uptake, hemolytic activities, toxicities, and immunomodulatory activities in different eukaryotic cell lines. The results indicate that disulfide bridge-containing cationic amphipathic peptides show superior antibacterial efficacies, are nontoxic and nonhemolytic, and mediate bacterial flocculation and killing, in the absence of external stimuli.

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Natarajan, K. A., and A. Das. "Surface chemical studies on ‘Acidithiobacillus’ group of bacteria with reference to mineral flocculation." International Journal of Mineral Processing 72, no. 1-4 (September 2003): 189–98. http://dx.doi.org/10.1016/s0301-7516(03)00098-x.

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Lee, Jimin, Dae-Hyun Cho, Rishiram Ramanan, Byung-Hyuk Kim, Hee-Mock Oh, and Hee-Sik Kim. "Microalgae-associated bacteria play a key role in the flocculation of Chlorella vulgaris." Bioresource Technology 131 (March 2013): 195–201. http://dx.doi.org/10.1016/j.biortech.2012.11.130.

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Rao, S. S., I. G. Droppo, C. M. Taylor, and B. K. Burnison. "Freshwater Bacterial Aggregate Development: Effect of Dissolved Organic Matter." Water Quality Research Journal 26, no. 2 (May 1, 1991): 163–72. http://dx.doi.org/10.2166/wqrj.1991.010.

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Abstract Suspended sediment particles and bacteria because of their surface area and charge, may play a role in the binding of aquatic contaminants. Little is known, as to what degree each of these factors play in the formation of suspended aggregates. Flocculation of particles can alter their hydrodynamic properties in aquatic environments and therefore may have significant implications for contaminant transport. In this study, we examine the role dissolved organic carbon plays in the production of bacterial aggregates as a first step to gaining a better understanding of bacterial-particle interactions and suspended particulate formation. Data indicated that an order of magnitude increase in bacterial population occurred due to the utilization of algal organic matter. This increase in bacterial density was closely accompanied by an increase in the size of the median bacterial aggregate from approximately 8 µm to 16 µm. This observation suggests that there is a greater potential for the sorption of aquatic contaminants by the aggregates.

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Bible, Amber N., Gurusahai K. Khalsa-Moyers, Tanmoy Mukherjee, Calvin S. Green, Priyanka Mishra, Alicia Purcell, Anastasia Aksenova, Gregory B. Hurst, and Gladys Alexandre. "Metabolic Adaptations of Azospirillum brasilense to Oxygen Stress by Cell-to-Cell Clumping and Flocculation." Applied and Environmental Microbiology 81, no. 24 (September 25, 2015): 8346–57. http://dx.doi.org/10.1128/aem.02782-15.

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ABSTRACTThe ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacteriumAzospirillum brasilensenavigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motileA. brasilensecells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Cell-to-cell clumping may thus license diazotrophy to microaerophilicA. brasilensecells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists.

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Palmgren, R., F. Jorand, P. H. Nielsen, and J. C. Block. "Influence of oxygen limitation on the cell surface properties of bacteria from activated sludge." Water Science and Technology 37, no. 4-5 (February 1, 1998): 349–52. http://dx.doi.org/10.2166/wst.1998.0663.

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Cell surface hydrophobicity is believed to be important to flocculation in activated sludge and biofilm systems. Optimization of these processes includes changes in the growth conditions of the bacteria. A number of factors influence cell surface hydrophobicity. The influence of oxygen on the cell surface hydrophobicity of 4 bacteria isolated from activated sludge was tested. The bacteria were grown in batch cultures with and without oxygen limitation. It was found that oxygen limitation generally caused a lowering of the cell surface hydrophobicity. The study also showed that there are many difficulties in measuring cell surface hydrophobicity since other cell surface properties, such as surface charge, influence the measurement methods. The MATH test was employed to establish how assay conditions influenced the results.

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Hiruma, Sumiyo, Masayuki Ishihara, Shingo Nakamura, Yoko Sato, Haruka Asahina, Koichi Fukuda, Tomohiro Takayama, Kaoru Murakami, and Hidetaka Yokoe. "Bioshell Calcium Oxide-Containing Liquids as a Sanitizer for the Reduction of Histamine Production in Raw Japanese Pilchard, Japanese Horse Mackerel, and Chub Mackerel." Foods 9, no. 7 (July 21, 2020): 964. http://dx.doi.org/10.3390/foods9070964.

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Recently, there has been an increase in the number of food poisoning cases associated with histamine in food, mainly in relation to histamine in fish. Here, we investigated methods to decrease histamine levels in Japanese pilchard, Japanese horse mackerel, and chub Mackerel, stored at 10 °C using various concentrations of heated scallop bioshell calcium oxide (BiSCaO) suspension, dispersion (BiSCaO + Na2HPO4), colloidal dispersion (BiSCaO + NapolyPO4), scallop shell powder (SSP) Ca(OH)2 in pure water (PW) or saline, and BiSCaO water. BiSCaO in a high alkaline pH solution chemically decomposes histamine poorly, but the partial flocculation/precipitation of histamine was observed with 1 and 0.2 wt.% BiSCaO dispersion and BiSCaO colloidal dispersion, respectively. Cleaning fish samples with BiSCaO suspension, dispersion, colloidal dispersion, or BiSCaO water remarkably reduced histamine levels and normal bacterial flora (coliform bacteria (CF) and total viable bacterial cells (TC)) after storage for four days at 10 °C, while much higher histamine levels were observed after cleaning with saline. These results suggest that cleaning fish with BiSCaO dispersion, colloidal dispersion, or BiSCaO water can significantly reduce histamine levels through their bactericidal activity against histamine-producing bacteria.

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Kjærgaard, Kristian, Mark A. Schembri, Henrik Hasman, and Per Klemm. "Antigen 43 from Escherichia coli Induces Inter- and Intraspecies Cell Aggregation and Changes in Colony Morphology of Pseudomonas fluorescens." Journal of Bacteriology 182, no. 17 (September 1, 2000): 4789–96. http://dx.doi.org/10.1128/jb.182.17.4789-4796.2000.

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ABSTRACT Antigen 43 (Ag43) is a surface-displayed autotransporter protein ofEscherichia coli. By virtue of its self-association characteristics, this protein is able to mediate autoaggregation and flocculation of E. coli cells in static cultures. Additionally, surface display of Ag43 is associated with a distinct frizzy colony morphology in E. coli. Here we show that Ag43 can be expressed in a functional form on the surface of the environmentally important Pseudomonas fluorescens strain SBW25 with ensuing cell aggregation and frizzy colony types. Using green fluorescence protein-tagged cells, we demonstrate that Ag43 can be used as a tool to provide interspecies cell aggregation betweenE. coli and P. fluorescens. Furthermore, Ag43 expression enhances biofilm formation in P. fluorescens to glass surfaces. The versatility of this protein was also reflected in Ag43 surface display in a variety of other gram-negative bacteria. Display of heterologous Ag43 in selected bacteria might offer opportunities for rational design of multispecies consortia where the concerted action of several bacterial species is required, e.g., waste treatment and degradation of pollutants.

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Weise, Andrea Marga, and Kenneth Lee. "THE EFFECT OF CLAY-OIL FLOCCULATION ON NATURAL OIL DEGRADATION." International Oil Spill Conference Proceedings 1997, no. 1 (April 1, 1997): 955–56. http://dx.doi.org/10.7901/2169-3358-1997-1-955.

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ABSTRACT Small-scale shaker flask experiments were conducted over 56 days with a weathered crude oil to investigate the significance of clay-oil flocculation processes on natural oil degradation rates. Clay-oil flocculation processes mediated the transfer of oil from solid surfaces into the aqueous phase where oil biodegradation rates are higher. As a result, within 7 days, 34% of the total n-alkanes (n-C12 to n-C35) were degraded in the oiled flasks containing mineral fines whereas no significant degradation was observed in flasks without mineral fines. After 56 days, only 25% and 48% of the n-alkane fraction remained in the flasks treated with and without mineral fines, respectively. No significant difference was observed between treatments for a selected number of 2-4 ring aromatic compounds. Microbiological results that showed an increase in the numbers of oil-degrading bacteria supported the results and conclusions derived from the chemical data.

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Olubayi, Olubayi, Rodulio Caudales, Amy Atkinson, and Carlos A. Neyra. "Differences in chemical composition between nonflocculated and flocculated Azospirillum brasilense Cd." Canadian Journal of Microbiology 44, no. 4 (April 1, 1998): 386–90. http://dx.doi.org/10.1139/w98-002.

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A two-step broth replacement method was used to induce Azospirillum brasilense Cd bacteria to flocculate in vitro. Nonflocculated and flocculated cells were compared with regard to total cellular lipid composition, fatty acid profiles, and poly-beta-hydroxybutyrate (PHB), protein, and carbohydrate contents. The fatty acid profiles of nonflocculated and flocculated cells were qualitatively identical. Two unsaturated fatty acids, octadecanoate (18:1 cis-9) and hexadecanoate (16:1 cis-9), accounted for approximately 80% of the total fatty acid content in both phenotypes. The major lipids in nonflocculated and flocculated A. brasilense Cd cells were phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine. The process of flocculation also resulted in the synthesis de novo of a glycolipid and cardiolipin. Flocculation also resulted in a decrease in total cellular protein and lipid content and a proportional increase in total cellular PHB and carbohydrate content. Results indicated that the two-step broth replacement procedure was an effective means for the in vitro production of the stress-tolerant A. brasilense Cd cells with high PHB contents, which are desirable in commercial agricultural inocula. The PHB content of flocculated cells reached 60-65% of cell dry weight.Key words: Azospirillum, flocculation, poly-beta-hydroxybutyrate, PHB, lipid, protein, carbohydrate, fatty acid.

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Kakii, Kazuo. "Role of Metallic Ions in the Flocculation of Activated Sludge and Sludge-Constituting Bacteria." Japan journal of water pollution research 13, no. 5 (1990): 273–77. http://dx.doi.org/10.2965/jswe1978.13.273.

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Jansson, Linda, Ronnie Eriksson, Johannes Hedman, and Moa Lavander. "Evaluation and modification of lanthanum-based flocculation for isolation of bacteria from water samples." Biotechnology Reports 19 (September 2018): e00267. http://dx.doi.org/10.1016/j.btre.2018.e00267.

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Hanumantha Rao, K., Annamaria Vilinska, and I. V. Chernyshova. "Microorganisms in Bioflotation and Bioflocculation: Potential Application and Research Needs." Advanced Materials Research 71-73 (May 2009): 319–28. http://dx.doi.org/10.4028/www.scientific.net/amr.71-73.319.

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Conventionally, physico-chemical methods are used in mineral processing for recovering value minerals from ores. The ageing of ore processing tailings and waste rocks, and mining tailings contamination by chemical reagents constitute a major threat to the environment. It is imperative to develop novel economically more efficient and environmentally benign methods of flotation and waste processing, exploiting the intriguing and exciting ability of bacteria to selectively modify the surface properties of solids. Microorganisms have not only facilitate hydrometallurgical leaching operations but have also show a great promise in mineral beneficiation processes such as flotation and flocculation. Several laboratory investigations revealed that microorganisms could function similar to traditional reagents. Microorganisms have a tremendous influence on their environment through the transfer of energy, charge, and materials across a complex biotic mineral-solution interface. The bio-modification of mineral surfaces involves the complex action of microorganism on the mineral surface. The manner, in which bacteria affect the surface reactivity and the mechanism of bacteria adsorption, is still unknown and accumulation of the primary data in this area is only starting. The bio-flotation and bio-flocculation processes concern the mineral response to the bacterium presence, which is essentially interplay between microorganism and the physicochemical properties of the mineral surface, such as the atomic and electronic structure, the net charge/potential, acid-base properties, and wettability of the surface. There is an urgent need for developing basic knowledge that would underpin biotechnological innovations in the natural resource (re)processing technologies that deliver competitive solutions.

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Williams, Frances E., Andrew K. Lee, Sanaz Orandi, Sarah K. Sims, and David M. Lewis. "Moringa oleifera functionalised sand – reuse with non-ionic surfactant dodecyl glucoside." Journal of Water and Health 15, no. 6 (September 19, 2017): 863–72. http://dx.doi.org/10.2166/wh.2017.241.

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Abstract Moringa oleifera seeds are well known for their ability to cause flocculation in turbid water and facilitate bacterial inhibition. These effects are due to the cationic polypeptide MO2.1, which affects the surface charge of suspended particles and causes lysis of bacterial cells. However, the attachment of bacteria to MO2.1 prevents further bacterial attachment, reducing the effectiveness of the seeds. This research investigated the effect of surfactants on functionality and reuse of Moringa seeds to develop a sustainable water treatment technique. The seed extracts (MO2.1) were used with a functionalised sand system, and the sands were exposed to commercially available (ionic and non-ionic) surfactants, dodecyl glucoside and sodium dodecyl sulfate. Artificially polluted water contaminated with Escherichia coli was used to evaluate the efficiency of the system. The non-ionic surfactant was found to be effective at separating E. coli from the functionalised sand without the detachment of the MO2.1 and subsequent loss of the system efficiency. This was successfully repeated four times. The results demonstrated a sustainable, reusable technique to inhibit bacterial contamination in water.

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Hong, B. H., M. M. Joe, G. Selvakumar, K. Y. Kim, J. H. Choi, and T. M. Sa. "Influence of salinity variations on exocellular polysaccharide production, biofilm formation and flocculation in halotolerant bacteria." Journal of Environmental Biology 38, no. 4 (July 1, 2017): 657–64. http://dx.doi.org/10.22438/jeb/38/4/mrn-284.

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Journal articles on the topic 'Bacteria. Flocculation'

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