Microbial Flocculant Research Articles

Preliminary Screening of Microorganisms Producing Flocculent

In order to reduce the production cost of Microbial Flocculation，this article uses the cheap straw-inorganic nitrogen medium，directly domesticated and screened out a stable and efficient microbial flocculant producing strain B-15，which has better flocculation on kaolin clay suspension system. Preliminary identify as bacillu, the strain produce flocculant has flocculating rate of 81.08% for suspension.

Zeolite and fungi’s flocculability of simulated wastewater containing heavy metal ions or phosphorus

This paper focuses on the flocculability of simulated wastewater containing heavy metal ions (Fe3+, Cd2+) or phosphorus by zeolite, microbial flocculants (MBF) produced by Aspergillus niger and the composite flocculant composed of zeolite and MBF. The main results are presented as follows: zeolite was a good flocculant when the contamination of the three simulated wastewaters was low, but the treated water is of turbidness and the particles in it are hard to precipitate. The MBF have a good flocculability toward Fe3+ wastewater, as well as particulate matter. Significant changes in flocculability occurred after adding the composite flocculant in different simulated wastewaters, the best or least effect respective for Fe3+ and Cd2+ wastewater. The research we have done shows that the method by which the composite flocculant is used to treat the wastewater containing heavy metal ions or phosphorus provides important reference value for practical application.

Enhanced dewatering of waste sludge with microbial flocculant TJ-F1 as a novel conditioner

Microbial flocculant (MBF) TJ-F1 with high flocculating activity was investigated to be used as a novel conditioner for the enhanced dewaterability of the waste sludge from wastewater treatment plant (WWTP). The experimental results showed that TJ-F1 was better than poly(acrylamide [2-(Methacryloyloxy)ethyl]trimethylammonium chloride) (P(AM-DMC)), the most commonly used conditioner in China, in improving the dewaterability of the waste sludge in terms of both the specific resistance in filtration ( SRF) and the time to filter ( TTF). The key parameters influencing the dewaterability of the waste sludge conditioned by TJ-F1, including the system pH, CaCl 2 concentration and TJ-F1 concentration, were systematically investigated. The favorite pH for the conditioning process was around the neutral. CaCl 2 was found to be a good conditioning aid to TJ-F1. A right dosage of TJ-F1 was decisive for the conditioning process. The optimized conditioning process is that about 0.17% (w/w) TJ-F1 and 1.3% (w/w) CaCl 2 are added into the sludge, and then the system pH was adjusted to 7.5. The compound use of TJ-F1 and P(AM-DMC) was also testified to be feasible in improving the dewaterability of the waste sludge.

Study on treatment of midcourse wastewater in papermaking factory with microbial flocculant

Study on treatment of midcourse wastewater in papermaking factory with microbial flocculant

Microbial flocculation by Bacillus mucilaginosus: Applications and mechanisms

Microbiological flocculation in wastewater by a strain of Bacillus mucilaginosus was examined and the flocculation mechanism was investigated using Coomassie brilliant blue reaction, Anthrone reaction, thin-layer chromatography (TLC), scanning electronic microscope, and infrared spectroscopy. The GY03 strain, isolated from farmland soil, was identified as B. mucilaginosus by its morphology and 16S rDNA sequence. Cultivated in a nitrogen-free medium, the flocculation material (bacterium–mineral complex) was used to treat domestic, brewage, and pharmaceutical wastewater. On the basis of one-way experimental results, orthogonal experiments were carried out and the optimum processing conditions of the microbial flocculants were obtained. In the optimal conditions, the maximal removal ratio of COD in domestic, brewage, and pharmaceutical wastewater reached 74.6%, 70.5%, and 66.2%, respectively; the maximal removal ratio of BOD was 42.3%, 77.4%, and 41.7%, respectively; and the maximal removal of SS amounted 93.3%, 93.6%, and 88.4%, respectively. The treatment to kaolin suspended liquid by the GY03 strain may act as a model of studying microbial flocculation mechanisms in which bridging and charge neutralization hypothesis were proposed as the critical reasons based upon the experimental observations.

Non-parallelism between the effect of microbial flocculants on sewerage disposal and the flocculation rate

This paper dealt with non-parallelism between the effect of microbial flocculant (MBF) on sewerage disposal and the flocculation rate, the high flocculation rate doesn’t mean the fine disposal effectiveness, and revealed the problem encountered when the exclusive parameter — flocculation rate is used to evaluate the effect of MBF on sewerage disposal. The results showed that MBF made from different carbon sources have some influence on the effectiveness of sewerage disposal; flocculation rate cannot authentically reflect the status of sewerage disposal. When the exclusive parameter — flocculation rate is used to evaluate the effect of MBF on sewerage disposal, it would be exaggerated, especially in disposing COD-low sewerage. The authors considered that when flocculation rate is used to evaluate the effect of MBF on sewerage disposal, it is better to take COD-removal rate into account.

Study on the flocculability of metal ions byBacillus mucilaginosus GY03 strain

This study deals with the flocculability of two types of metal ions by Bacillus mucilaginosus GY03 Strain, with an emphasis on the influence of pH conditions, volume and time of flocculants produced by GY03 Strain on the adsorption of metal irons such as Pb(superscript 2+) and Mn(superscript 2+) and the capabilities of flocculants to adsorb metal ions of different concentrations. The results showed that microbial flocculants produced by Bacillus mucilaginosus GY03 Strain are highly Capable of flocculating metal ions, but show different effectiveness with respect to the adsorption of Pb(superscript 2+) and Mn(superscript 2+). In accordance with the experimental data and actual waste-water treatment conditions, the relevant regression equation of flocculation has been deduced, which has found some application in practice. The experimental results of this study demonstrated that microbial flocculants produced by Bacillus mucilaginosus can be used to treat metallic ion-containing waste water. In practical application the volume of microbial flocculants required and flocculation conditions should be taken into comprehensive consideration in accordance with the properties of metal ions, the composition of anions and the solubility of other metals, in combination with the cost and effectiveness of flocculants to be used. Flocculant used in this experiment has the advantages of being applied over a wide range of pH values, small flocculant volume, and rapid speed of flocculation. So this kind of flocculant is within excellent prospect of application.

Culture Conditions for Flocculant Production by Paenibacillus polymyxa BY-28

A new flocculant-producing bacterium Paenibacillus polymyxa BY-28 was isolated from soil. The optimal culture media for flocculant production were 2% glucose, 0.3% KH2PO4, 0.1% bean cake powder, 0.05% CaCl2 and 0.05% (w/v) MgSO4·7H2O. Optimal culture temperature was 30°C and pH was 6–8. Flocculants produced under optimal conditions efficiently aggregated various organic and inorganic suspensions in simulated water as well as in wastewater by addition of bivalent and trivalent cations Ca2+. From Zeta-potential measurement, the dominant role of microbial flocculant in the flocculation process is based on the bridging mechanism, and the role of CaCl2 is to decrease the negative electrical charge of the Kaolin clay particles.

Harvesting of Chlorella vulgaris using a bioflocculant from Paenibacillus sp. AM49

Microbial flocculants for harvesting mass cultured Chlorella vulgaris were screened and that from Paenibacillussp. AM49 was identified as the best. The flocculation efficiency of this bioflocculant increased with the pH within a range of pH 5–11 and was 83%, which was higher than the 72% and 78% produced by aluminum sulfate and polyacrylamide, respectively. The highest flocculation efficiency was with 6.8 mm CaCl2 as co-flocculant. The bioflocculant from Paenibacillussp. AM49 can be used effectively to harvest C. vulgaris from large-scale cultures.

Effects of harvesting method and growth stage on the flocculation of the green alga Botryococcus braunii

Flocculating activity was determined to evaluate the effective harvesting method and an optimal growth stage for the recovery of the green alga Botryococcus braunii growing in batch cultures. Flocculating activity was highest at 2 weeks of incubation, regardless of harvesting methods. The degree of flocculation was different with harvesting methods and growth stages. A high pH value (pH 11) was more effective for flocculation than treatment with aluminium sulphate or a microbial flocculant, Pestan, until the third week of incubation. The lipid content of the algae on a dry weight basis was unaffected by harvesting methods. These results indicate that the most effective harvesting method is to adjust pH to 11 after 2 weeks of incubation.

95/04259 Sustainable resource use: The search for meaning

The colloidal properties of biogenic elemental sulfur (S0) cause solid–liquid separation problems, such as poor settling and membrane fouling. In this study, the separation of S0 from bulk liquids was performed using flocculation. Polyaluminum chloride (PAC), polyacrylamide (PAM) and microbial flocculant (MBF) were compared to investigate their abilities to flocculate S0 produced during the treatment of sulfate-containing wastewater. A novel approach with response surface methodology (RSM) was employed to evaluate the effects and interactions of flocculant dose, pH and stirring intensity, on the treatment efficiency in terms of the S0 flocculation and the supernatant turbidity removal. The dose optimization results indicated that the S0 flocculation efficiency decreased in the following order PAC > MBF > PAM. Optimum S0 flocculation conditions were observed at pH 4.73, a stirring speed of 129 r/min and a flocculant dose of 2.42 mg PAC/mg S. During optimum flocculation conditions, the S0 flocculation rate reached 97.53%. Confirmation experiments demonstrated that employing PAC for S0 flocculation is feasible and RSM is an efficient approach for optimizing the process of S0 flocculation. The results provide basic parameters and conditions for recovering sulfur during the treatment of sulfate-laden wastewaters.

微生物が生産する新しいバイオ凝集剤

Rhodococcus erythropolis produces a kind of microbial flocculant. This bioflocculant was able to efficiently flocculate all the suspended solids tested in an aqueous solution. Among those tested were microorganisms such as E. coli and baker's yeast, activated sludge, algae, kaolin clay, muddy water, river bottom sediment, ash and charcoal powder. The bioflocculant NOC-1 from Rhodococcus erythropolis has a wide flocculating activity against both organic and inorganic materials.From an aqueous solution of a water soluble pigment, removal of the water soluble pigment was attained by the bioflocculant NOC-1. The bioflocculant NOC-1 was able to efficiently flocculate and precipitate the soluble pigment in an aqueous solution tested. Among those efficiently tested were black ink, melanoidin pigment (blackish brown pigment) and black colored pigment of the black liquor of pulping industry.This bioflocculant was purified, and was found to be composed mainly of protein. This bioflocculant is biodegradable flocculant which causes no problem of environmental pollution.

Screening for and Characteristics of Microbial Flocculants

Fourteen strains of the genera Rhodococcus, Nocardia, and Corynebacterium were found to produce substances which flocculate kaolin clay. Rhodococcus erythropolis produces a kind of the microbial flocculant. It had very interesting and unique flocculating characteristics. It could efficiently flocculate all suspended solids in aqueous solution tested. Among those effectively tested were microorganisms such as E. coli and alcohol yeast, activated sludge, Microcystis aeruginosa (AOKO), kaolin clay, muddy water, river dredging muddy water, river bottom sediment (HEDORO), ash from a steam-power station, and chacoal. These results indicated that the flocculant from R. erythropolis had a wide flocculating activity against both organic and inorganic materials. Cationic ions such as Ca2+ also significantly increased the flocculating activity.

Microbial flocculants. Part I Screening for and characteristics of microbial flocculants.

Fourteen strains of the genera Rhodococcus, Nocardia, and Corynebacterium were found to produce substances which flocculate kaolin clay.Rhodococcus erythropolis produces a kind of the microbial flocculant. It had very interesting and unique flocculating characteristics. It could efficiently flocculate all suspended solids in aqueous solution tested. Among those effectively tested were microorganisms such as E. coli and alcohol yeast, activated sludge, Microcystis aeruginosa (AOKO), kaolin clay, muddy water, river dredging muddy water, river bottom sediment (HEDORO), ash from a steam-power station, and chacoal. These results indicated that the flocculant from R. erythropolis had a wide flocculating activity against both organic and inorganic materials. Cationic ions such as Ca2+ also significantly increased the flocculating activity.

Flocculant production by Paecilomyces sp. Taxonomic studies and culture conditions for production.

Screening of microorganisms producing a new kind of flocculating substance was carried out. A fungus that produced a large amount of a strong microbial cell flocculant was isolated from soil. The fungus was classified as a Paecilomyces species. The substance produced showed very interesting and unique flocculation characteristics. It could efficiently flocculate all tested suspended solids in aqueous solution, and flocculation was practically not affected by ionic strength, pH or temperature.The influence of components of the culture medium upon the flocculant production by Paecilomyces sp. 1-1 was studied. Addition of hydrolysates of casein such as casamino acid and polypeptone stimulated the production of the flocculant. A high concentration of calcium ions also significantly increased the mycelial growth and the production of the flocculant. Under the optimum cultural conditions, a 500-fold dilution of the culture filtrate could efficiently flocculate and sediment E. coli cells.

Studies on bio-flocculation with the flocculants produced by microorganisms. II. Purification and chemical analysis of microbial cell flocculant produced by Aspergillus sojae AJ7002.

A bio-flocculant was isolated from the culture broth of Asp. sojae AJ 7002. It was partially purified by acetone or ethanol precipitation, by ion-exchange and gel chromatography, and by dialysis. The isolated polymer possessed chemical characteristics of a poly-hexosamine and a protein. Glucosamine and galactosamine were not acetylated. The flocculant contained 2-ketogluconic acid, but sulfur or phosphorus was not detected. This flocculant was thermo-stable and its activity varied with pH. It was suggested that the hexosamine moiety in the polymer played a major role in bio-flocculation, assisted by protein portion in enlargement of the molecular weight of the flocculant, and by 2-ketogluconic acid in endowing it with amphoteric character.

Studies on bio-flocculation with the flocculants produced by microorganisms. III. Conditions for production of microbial cell flocculant by Aspergillus sojae AJ7002.

Cultivation is reported on Aspergillus sojae AJ 7002 which synthesized an extracellular bio-flocculant. Growth studies in shaking flasks and fermentors were conducted to obtain higher flocculant production. The highest level of polymer accumulation was attained after 48_??_72 hr cultivation at 30_??_34°C. The favorable substrates for polymer formation were casein, yeast extract, polypepton and amino acids, such as glutamic acid and alanine. The addition of saccharides to the medium was found to reduce the pH of the culture broths, and hence inhibit the accumulation of flocculant in the culture broth. The finding that the product was a single substance from the early stage of fermentation suggested that the polymer was not a product of cell autolysis. The components of the polymer which were produced by Asp. sojae did not vary even if the medium composition or culture condition changed. The addition of 2-ketogluconic acid, which is one of the constituents of the polymer increased the flocculating activity of the culture medium.

Studies on bio-flocculation with the flocculants produced by microorganisms. I. Screening, isolation, and some properties of microbial cell flocculants.

Nineteen out of 214 strains of microorganisms including moulds, bacteria, actinomycetes and yeasts, which were selected from the culture collection of our laboratory were found to produce the substances which flocculate Saccharomyces cerevisiae AJ 4005 (baker's yeast). Among them are Aspergillus sojae, Anixiella reticulata, Geotrichum candidum, Eupenicillium crustaceus, Circinella sydowi, Monascus anka, Sordaria fimicola, Pseudomonas fluorescens, Staphylococcus aureus, Corynebacterium brevicale, Brevibacterium insectiphilum, Streptomyces vinaceus. The flocculants in the culture broth of these microorganisms precipitated readily by addition of acetone, and flocculated various microorganisms nonspecifically. The flocculant produced by Asp. sojae AJ 7002 sedimented activated sludge well.