Bioflocculant Production Research Articles

Isolation, Identification and Characterization of Bioflocculant-Producing Bacteria from Activated Sludge of Vulindlela Wastewater Treatment Plant

The low microbial flocculant yields and efficiencies limit their industrial applications. There is a need to identify bacteria with high bioflocculant production. The aim of this study was to isolate and identify a bioflocculant-producing bacterium from activated sludge wastewater and characterise its bioflocculant activity. The identification of the isolated bacterium was performed by 16S rRNA gene sequencing analysis. The optimal medium composition (carbon and nitrogen sources, cations and inoculum size) and culture conditions (temperature, pH, shaking speed and time) were evaluated by the one-factor-at-a-time method. The morphology, functional groups, crystallinity and pyrolysis profile of the bioflocculant were analysed using scanning electron microscope (SEM), Fourier transform infrared (FTIR) and thermogravimetric (TGA) analysis. The bacterium was identified as Proteus mirabilis AB 932526.1. Its optimal medium and culture conditions were: sucrose (20 g/L), yeast extract (1.2 g/L), MnCl2 (1 g/L), pH 6, 30 °C, inoculation volume (3%), shaking speed (120 rpm) for 72 h of cultivation. SEM micrograph revealed the bioflocculant to be amorphous. FTIR analysis indicated the presence of hydroxyl, carboxyl and amino groups. The bioflocculant was completely pyrolyzed at temperatures above 800 °C. The bacterium has potential to produce bioflocculant of industrial importance.

Studies on Bioflocculant Production by Pseudoalteromonas sp. NUM8, a Marine Bacteria Isolated from the Circulating Seawater

Studies on Bioflocculant Production by Pseudoalteromonas sp. NUM8, a Marine Bacteria Isolated from the Circulating Seawater

Reusing sago mill effluent as a substrate for bio-based polymeric flocculant fermentation: Optimisation of operational conditions

Sago mill effluent (SME) contains high levels of organic material that can be reused as feedstock for a nutrient source in polymeric bioflocculant fermentation. In this study, SME was reused for bio-based polymeric flocculant or bioflocculant production and was optimised using central composite design (CCD) to obtain a high yield of bioflocculants, chemical oxygen demand (COD) removal, and enhanced flocculating activity. The operational conditions involved in the optimisation were temperature (30–40°C), fermentation time (24–72 h), incubator speed (100–200 rpm), and fermentation medium (sterile and non-sterile SME). Based on the analysis, the optimal conditions for bioflocculant production were a temperature of 30°C, fermentation time of 32 h, incubator speed of 100 rpm, and cultivation in non-sterile SME medium, with bioflocculant yield of 201 mg/L, 65.5% COD removal, and 88.4% flocculating activity. X-ray diffraction analysis showed that the bioflocculants contained C, O, Ca, Mn, Si, P, S, Ca, and Mn. Zeta potential analysis indicated that the bioflocculants had a negative charge, while analyses via liquid chromatography-mass spectrometry (LC-MS) revealed that the bioflocculants consisted of glucose, xylose, and rhamnose. Therefore, reusing SME at optimum operational conditions to produce a new product and minimise waste discharge to the environment could support and move towards the circular economy concept. • Sago mill effluent contains valuable organic materials. • Sago mill effluent was used for a bio-based polymeric flocculant fermentation. • Bio-based polymeric flocculant production was optimised using central composite design. • Good COD removal of 65.5% and flocculating activity of 88.4%, were achieved. • Bio-based polymeric flocculant consisted of glucose, xylose and rhamnose.

Preparation of a bacterial flocculant by using caprolactam as a sole substrate and its application in amoxicillin removal

High cost is one of the limiting factors in the industrial production of bioflocculant. Simultaneous preparation of bioflocculant from the contaminants in wastewater was considered as a potential approach to reduce the production cost. In this study, caprolactam was verified as sole feedstock for the growth of strain Alcaligenes faecalis subsp. phenolicus ZY-16 in batch experiments. Chemical analysis showed that the as-prepared MBF-16 consisted of heteropolysaccharides (88.3%) and peptides (9.4%). XPS result indicated the plentiful acylamino, hydroxyl and amino groups in MBF-16, which have an indispensable role in amoxicillin flocculation. The flocculation of amoxicillin can be well stimulated by Freundlich isotherm equation, and the Kf was up to 178.6524 for amoxicillin. The kinetic fitting results proved that the flocculation of amoxicillin by MBF-16 was chemisorbed. This contribution may develop a novel technology for the preparation of bacterial flocculants that can consume toxic substrates (caprolactam) and have potential applications in amoxicillin removal.

Bioflocculant production by marine psychrotolerant Psychrobacter cibarius H41A KF207755 with its special role in silver nanoparticles production

The present study screened 23 previously isolated and identified marine psychrotolerant bacterial strains for the production of bioflocculant. Factors affecting the production process as well as the bioflocculant activity, in addition to the biosynthesis and the characterization of silver AgNPs were carried out. Psychrobacter cibarius H41 AKF207755 exhibited high bioflocculation activity at 75.3%. The effect of different physical and nutritional factors on the bioflocculant production process by P. cibarius H41Awas determined. The bioflocculating activity was increased to 82.1% after incubation for 60 h and to 84.7% at pH 6.5. Also, sucrose and urea improved the activity. The type of cations, pH level, and temperature were examined on the produced bioflocculant, which reached to 90.3% at pH 9 and to 92.1% at 70oC. The addition of FeSO4 raised the bioflocculant activity up to 94.0%. The concentrations of total protein, total carbohydrate, and total lipid were estimated for the partially purified bioflocculant as; 20.285, 31.215, and 12.2 gL-1, respectively. It was found that the AgNPs can be synthesized using the bioflocculant, which remains stable for up to 16 months. Characterization of these AgNPs by UV-spectroscopy, FTIR, and TEM analyses takes place. The pH 11 supported the maximum synthesis of AgNPs at 2 mM AgNO3. TEM revealed that the size of the produced AgNPs ranged from 1.31 nm to17.45 nm and no agglomeration was observed. Upon the applicable level, the antimicrobial property of AgNPs synthesized by the bioflocculant of P. cibarius H41A KF207755 was confirmed. The concentration dosage that gave the optimum flocculating activity (92.5%) was 4.0 mgmL-1.

Marine Actinobacteria Bioflocculant: A Storehouse of Unique Biotechnological Resources for Wastewater Treatment and Other Applications

The bioactive compounds produced by actinobacteria have played a major role in antimicrobials, bioremediation, biofuels, enzymes, and anti-cancer activities. Biodegradable microbial flocculants have been produced by bacteria, algae, and fungi. Microbial bioflocculants have also attracted biotechnology importance over chemical flocculants as a result of degradability and environmentally friendly attributes they possess. Though, freshwater actinobacteria flocculants have been explored in bioflocculation. Yet, there is a paucity of information on the application of actinobacteria flocculants isolated from the marine environment. Similarly, marine habitats that supported the biodiversity of actinobacteria strains in the field of biotechnology have been underexplored in bioflocculation. Hence, this review reiterates the need to optimize culture conditions and other parameters that affect bioflocculant production by using a response surface model or artificial neural network.

Optimized production and characterization of cation-independent bioflocculant produced by Klebsiella sp. 59L.

The cation-independent bioflocculant (59LF) extracted from Klebsiella sp. 59L was characterized. 59LF consisted of protein (4.8%) and total sugar (85.2%) with high molecular weight (93.82% of 2120 kDa), and total sugar was composed of 76.45% of neutral sugar, 3.65% of uronic acid, and 1.43% of amino sugar. Results indicated that 59LF was pH tolerant and thermally stable, and the maximum yield of 59LF was 4.078 g/L after 48 h culture. The optimal flocculating activity for Kaolin particles was obtained when the dosage of 59LF was 7.0 mg/L without additional metal ions as coagulant aids. Furthermore, the surface properties of 59LF were observed using a Fourier-transform infrared spectrophotometer and X-ray photoelectron spectroscopy, whereas a porous structure was detected by a scanning electron microscope. Thus, a primary flocculation mechanism of 59LF was proposed. This study provided a potential cation-independent bioflocculant with high productivity and low dosage in future application.

Production and Characterization of Bioflocculant by Freshwater Bacteria Recovered From Surface Water and Sediment Matrix

Production and Characterization of Bioflocculant by Freshwater Bacteria Recovered From Surface Water and Sediment Matrix

Optimization of bioflocculant production by bacteria isolated from oil-polluted soil and fermented maize effluent

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

Production of a bioflocculant from Enterobacter sp. P3 using brewery wastewater as substrate and its application in fracturing flowback water treatment.

A novel bioflocculant (BW-P3) was produced by a strain of Enterobacter sp. P3 using brewery wastewater as substrate and was further applied to remove the colored substance of fracturing flowback water. The optimum conditions for bioflocculant production were specified by the response surface methodology as COD of brewery wastewater 1487.77mg/L, glucose 8.94g/L and initial pH7.09, under which a bioflocculant yield of 1.274g/L could be reached. The BW-P3 consists of 79.12% polysaccharides and 15.63% protein. Results show that BW-P3 has a high molecular weight (921kDa) and contains functional groups (hydroxyl, amino, carbonyl, and acylamino) that likely contribute to flocculation. When using the BW-P3 to flocculate fracturing flowback water, the optimal dosage was 1g/L BW-P3 with addition of 100mg/L polymeric aluminum chloride as coagulant aid, and treated under 50°C at pH7. Under the optimal condition, the removal rates of chroma and suspended solids (SS) of the fracturing flowback water could reach 85% and 52%, respectively.

Production and purification of bioflocculants from newly isolated bacterial species: a comparative decolourization study of cationic and anionic textile dyes

ABSTRACT Bioflocculant-producing bacteria were isolated from various water reservoirs and sediments of the water treatment plant. Four promising strains were identified by standard biochemical methods and 16s rRNA gene sequencing. Bioflocculants were produced in a batch bioreactor of 3 L under optimized conditions. Fourier transformed infrared spectroscopy and scanning electron microscopy (SEM) were used to confirm the chemical and morphological nature of bioflocculants. Anionic and cationic textile dyes congo red (CR) and rhodamine-B (RB) decolourization efficiency by ethanol precipitated bioflocculants were accessed under different values of pH, temperature, dose of flocculant and presence of monovalent, divalent and trivalent cations. Bioflocculants of all the four isolates were found to be highly efficient in decolourization of dye from an aqueous medium with the removal rate up to 99.56%. The removal rate of CR and RB from aqueous medium was largely influenced by the physiochemical condition of the solution viz. pH, temperature, concentration of ions and dose of flocculants. The microbial bioflocculants are biodegradable and highly stable as well as possess abroad range of pH, temperature and ions tolerance range. So, they may be economical and can be greener substitutes for the present harsh chemical-based wastewater effluent treatment methods.

Production of bioflocculant using feather waste as nitrogen source and its use in recycling of straw ash-washing wastewater with low-density and high pH property

Straw ash-washing wastewater is generated in the process of straw combustion power generation and potash fertilizer production. The suspended solid particles in straw ash-washing wastewater are hard to be settled down due to its low-density and high pH properties which inhibit the application of traditional chemical flocculants. Bioflocculant has good advantages in flocculating activity, biodegradability and adaptability of wastewater pH fluctuation. However, high production cost limited the large-scale applications of bioflocculant in wastewater treatment. In this study, the feasibility of using feather waste as cheap alternative nitrogen source of alkaliphilic Bacillus agaradhaerens C9 to produce bioflocculant was investigated. The results showed that strain C9 could simultaneously produce keratinase and bioflocculant, and thereby producing bioflocculant (named as BFF) using feather waste as cheap nitrogen source. The optimal fermentation conditions for enzymatic hydrolysis of feather waste and BFF production was 40 g/L feather wastes, 16 g/L glucose, 37 °C and pH 9.5, and the highest yield of 2.5 g/L was obtained. Moreover, BFF was used to flocculate straw ash-washing wastewater which exhibits low-density and high pH properties, and the highest flocculating rate of 93.1% was achieved when 6.0 mg/L BFF was added. This study reported for the first time that feather waste was used as inexpensive alternative nitrogen source for producing bioflocculant which could treat straw ash-washing wastewater, thereby promoting the resourceful utilization of feather waste and the reuse of straw ash-washing wastewater.

Characteristics of methane and bioflocculant production by Methanosarcina spelaei RK-23

This study aimed to isolate a novel archaeon capable of simultaneously producing methane and bioflocculants. The isolated methanogen was identified as Methanosarcina spelaei RK-23 by molecular characterization. Strain RK-23 grew with different carbon sources, but acetate was found to be the most beneficial carbon source for the production of methane and bioflocculants. Moreover, RK-23 produced methane and bioflocculants within an initial pH range of 5.0–8.0, with an optimal pH for methane production of 6.5 and flocculating activity of 7.0. In addition, strain RK-23 exhibited tolerance to high-salinity conditions and produced methane and bioflocculants within 0–1.2 M NaCl, with an optimum NaCl concentration of 0.3 M. The methane production and flocculating activity of strain RK-23 under optimal culture conditions were 17.4 mmol methane/mol acetate and 95.6%, respectively. MBF-23 mostly consisted of 83.5% carbohydrates and 14.3% proteins. Furthermore, the bridging of adsorption is believed to be the main bioflocculation mechanism in this study.

Techno-economic analysis for extracellular-polymeric substances (EPS) production using activated sludge fortified with crude glycerol as substrate and its application in leachate treatment

Economic assessment of bio-flocculant production process has been carried out by SuperPro Designer where extracellular-polymeric substances (EPS) were produced using activated sludge fortified with crude glycerol in fermenter followed by centrifugation. Considering EPS concentration of 60 g/L in production fermenter at 96 h, the unit production cost for slime EPS was estimated to be $ 0.95/L. The unit price of S-EPS was sensitive to inoculum size and EPS productivity (EPS concentration and fermentation time) in the fermented broth. Economic analysis was also conducted for EPS aided leachate treatment. The unit leachate treatment cost was 7.78 $/m3 and was sensitive to S-EPS unit production cost. To get same leachate treatment cost as current industrial practice (4 $/m3), S-EPS unit production cost should lower down to $ 0.5/L. The process has several advantages: 1) sludge and crude glycerol valorization for bio-flocculant production 2) Leachate treatment using environment friendly bio-flocculant.

Bioconversion of citrus peel wastes into bioflocculants and their application in the removal of microcystins.

In this study, the mechanism for converting citrus peel wastes (CPW) into bioflocculants using Alcaligenes faecalis subsp. phenolicus ZY-16 was analysed. The results demonstrated that the ZY-16 strain could produce various lignocellulolytic enzymes, containing cellulase, hemicellulase, pectinase, protease, and ligninase, enhancing the hydrolysis of citrus peel wastes. Molecular distillation removes antimicrobial limonene, which could inhibit bioflocculant production. The optimal fermentation conditions with the highest bioflocculant yield (3.49g/L) were 38.79g/L of CPW, 35.54°C, and pH4.48. Furthermore, the bioflocculant was used to eliminate microcystins for the first time, and the highest removal efficiency (90.05%) was achieved at a pH of 3.0, after 800mg/L of bioflocculant was added into the microcystins solution (10mg/L) for 60min. Therefore, this paper demonstrated that CPW could be a cost-effective feedstock for the production of bioflocculants, which have potential application in microcystin removal.

Bioflocculant production using palm oil mill and sago mill effluent as a fermentation feedstock: Characterization and mechanism of flocculation

This study was conducted to examine the production of bioflocculants using agricultural wastewater as a fermentation feedstock under different temperatures and incubation times. The mechanism of flocculation was studied to gain a detailed understanding of the flocculation activity. The highest bioflocculant yield (2.03 g/L) at a temperature of 40 °C was produced in a palm oil mill effluent medium (BioF-POME). Bioflocculant produced from a fermented SME medium (BioF-SME) showed the highest activity. The flocculation tests for colour and turbidity removal from lake water indicated that BioF-SME and BioF-POME performed comparably to commercial alum. Analyses of the bioflocculants using liquid chromatography-mass spectrometry (LC-MS) found that the bioflocculants contained xylose and glucose. The mechanism study showed that flocculation occurred through charge neutralization and interparticle bridging between the bioflocculant polymer and the particles in the lake water. Thus, agricultural wastewater can be used as a fermentation feedstock for high-quality bioflocculants.

Production and characterization of bioflocculant via solid state fermentation process using oil palm empty fruit bunch fibers as substrate

Abstract Bioflocculant is an extracellular biopolymer substance secreted naturally by microorganisms during their growth. It has piqued the interest of many researchers due to its biodegradability, nontoxic properties, and potential as a substitute for conventional flocculant where its usage may lead to environmental and health issues. In the present study, Aspergillus niger DWB was used to investigate the production and characterization of bioflocculant. The bioflocculant was produced by utilizing agricultural residue from the oil palm industry, oil palm empty fruit bunch (OPEFB) fiber as the carbon source. The effect of pH of the medium, as well as the inoculum size on the bioflocculant production, was examined. The maximum bioflocculant yield obtained after 48 h of fermentation was 9.48%/g substrate under tested condition. In addition, the bioflocculant produced showed a good flocculating rate in kaolin suspension at pH 6, within 15 min of retention time and using 4 ml of bioflocculant dosage. The functional group of the extracted bioflocculant was determined using Fourier-transform infrared (FTIR) spectroscopy, which revealed the presence of hydroxyl and carboxyl groups. These functional groups attributed to their flocculating abilities. The results obtained from this study suggested that the agricultural waste, OPEFB fiber can serve as a suitable solid substrate in the production of bioflocculant.

Simultaneous nitriles degradation and bioflocculant production by immobilized K. oxytoca strain in a continuous flow reactor

High cost is one of the limiting factors in the industrial production of bioflocculant. Simultaneous preparation of bioflocculant from the contaminants in wastewater was considered as a potential approach to reduce the production cost. In this study, butyronitrile and succinonitrile were verified as sole nitrogen sources for the growth of strain K. oxytoca GS-4-08 in batch experiments. Moreover, more than 90 % of the mixed nitriles could be degraded in a continuous flow reactor, and the bioflocculant could be prepared simultaneously in the effluent. All the as-prepared bioflocculants exhibited high flocculation efficiencies of over 90 % toward Kaolin solution. FTIR and XPS results further unveiled that, the bioflocculant samples with abundance of carboxyl, amine and hydroxyl groups may play an important role on adsorption of Pd2+. The adsorption process could be well simulated by Freundlich model, and the Kf values were as high as 452.8 mg1−1/n l1/n g-1. The results obtained in this study not only confirm the technical feasibility for preparation of bioflocculant from various single nitrile and/or mixed nitriles, but also promise its economic feasibility.

Implications for industrial application of bioflocculant demand alternatives to conventional media: waste as a substitute.

The biodegradability and safety of the bioflocculants make them a potential alternative to non-biodegradable chemical flocculants for wastewater treatment. However, low yield and production cost has been reported to be the limiting factor for large scale bioflocculant production. Although the utilization of cheap nutrient sources is generally appealing for large scale bioproduct production, exploration to meet the demand for them is still low. Although much progress has been achieved at laboratory scale, Industrial production and application of bioflocculant is yet to be viable due to cost of the production medium and low yield. Thus, the prospects of bioflocculant application as an alternative to chemical flocculants is linked to evaluation and utilization of cheap alternative and renewable nutrient sources. This review evaluates the latest literature on the utilization of waste/wastewater as an alternative substitute for conventional expensive nutrient sources. It focuses on the mechanisms and metabolic pathways involved in microbial flocculant synthesis, culture conditions and nutrient requirements for bioflocculant production, pre-treatment, and also optimization of waste substrate for bioflocculant synthesis and bioflocculant production from waste and their efficiencies. Utilization of wastes as a microbial nutrient source drastically reduces the cost of bioflocculant production and increases the appeal of bioflocculant as a cost-effective alternative to chemical flocculants.

Bioconversion of lignocellulose and simultaneous production of cellulase, ligninase and bioflocculants by Alcaligenes faecalis-X3

Lignocelluloses have been used as carbon sources for bioflocculant production. However, the low bioconversion efficiency of lignocellulose to bioflocculants is a major challenge. In this study, a lignocellulolytic strain of Alcaligenes faecalis-X3 was cultivated in ramie bio-degumming wastewater. Optimal production of ligninase, cellulase and bioflocculants (MBF-X3) was evaluated. The highest activity of MBF-X3 under the optimal conditions of pH 6.0 at 48 h of fermentation was 95.44%, with the maximum production of ligninase and cellulase (0.27 and 0.12 U/mL, respectively). The crude ligninase and cellulase had optimum activities at pH 5.0 and 40 °C and pH 6.0 and 50 °C, respectively. The cellulase activity was increased by Mn2+, Ca2+, Zn2+, and Mg2+ at 1 mM. The ligninase activity was significantly enhanced in the presence of Zn2+ at 10 mM. The flocculating activity of MBF-X3 was not changed by the addition of any metal cation. The results demonstrated that A. faecalis possesses an excellent enzyme system for the efficient bioconversion of lignocellulose into MBF-X3. Additionally, MBF-X3 has a high flocculating efficiency of Disperse Blue-2BLN (85.7%) at a dose of 1.0 g/L.