Biopolymeric Flocculant Research Articles

Application, Synthesis, and Characterization of Cationic Galactomannan from Ruderal Species as a Wet Strength Additive and Flocculating Agent.

There has been a cumulative interest across the globe in substituting the synthetic materials with sustainable, economical, and biobased green alternatives for utilization in diverse industrial applications. Galactomannans are among the most important sustainable, biodegradable macromolecules abundantly produced by plants, which can be exploited for a range of end-use applications. Functionalization of the galactomannans may improve the physicochemical properties for diverse industrial applications. In the present study, the cationic derivative of Cassia tora gum, a 1:5 galactomannan, was synthesized under heterogeneous alkaline conditions using CHPTAC. The effect of each reaction parameter on the degree of substitution (DS) was investigated using Taguchi L16 orthogonal array. The optimized cationic product with DS 0.28 showed promising results as a biopolymeric flocculant for wastewater treatment and as a wet strength additive for improving the physical strength of paper prepared from old corrugated carton for its recycling. The optimized product was characterized by advanced spectroscopic methods.

Cationically functionalized amylopectin as an efficient flocculant for treatment of coal suspension

The present work deals with the development of a novel biopolymeric flocculant towards the treatment of coal suspension. Amylopectin has been chosen as natural polysaccharide to be modified towards the treatment of coal effluent. The synthetic methodology follows two basic steps: at first, amylopectin has been modified to cationically substituted amylopectin (Cat-AM) and then polyacrylamide chains have been grafted with Cat-AM through free radical polymerization. The graft copolymer (Cat-AM-g-PAAm) has been characterized using various characterization techniques including Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (1H-NMR), thermogravimetry (TGA), elemental analysis (CHN), field emission scanning electron microscopy (FESEM) analyses. Multiangle light scattering spectroscopy/gel permeation chromatography (MALSS/GPC) analysis reveals the gradual increase in average molecular weight from amylopectin to Cat-AM to Cat-AM-g-PAAm. The developed material demonstrates excellent efficacy towards the settling of coal suspension and even better as compare to a commercially available flocculant.

Evaluation of Fresh Water Actinomycete Bioflocculant and Its Biotechnological Applications in Wastewaters Treatment and Removal of Heavy Metals.

This study evaluated the potential of a biopolymeric flocculant produced by Terrabacter sp. isolated from Sterkfontein Dam, South Africa. Microbial flocculants aid the aggregation of suspended solutes in solutions, thus, suggesting its alternative application to inorganic and synthetic organic flocculants, which are associated with health-related problems. The 16S rDNA analysis revealed the bacteria to have 98% similarity to Terrabacter sp. MUSC78T and the sequence was deposited in the Genbank as Terrabacter sp. with accession number KF682157.1. A series of experimental parameters such as bioflocculant dosage, cations concentrations, pH, and application of the purified bioflocculant in wastewaters treatment were investigated. In the presence of glucose as a sole carbon source, Ca2+ as cation at pH 8, the optimal flocculating activity attained was 85%. Optimum bioflocculant dosage of 0.5 mg/mL was able to remove chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solids (SS), nitrate, and turbidity in dairy wastewater. In addition, the tested bioflocculant exhibited higher flocculating efficiency as compared to polyaluminum chloride, polyethylenime, and alum. Inductible coupled plasma optical emission spectroscopy (ICP-OES) analyses confirmed significant removal of 77.7% Fe, 74.8% Al, 61.9% Mn, and 57.6% Zn as representatives of heavy metals from treated dairy wastewater. Fourier transform infrared spectroscopy (FTIR) indicated the presence of carboxyl, hydroxyl, and amino groups in the purified bioflocculant which could be responsible for flocculation. Findings from this study showed the prospect of the studied bioflocculant as an alternative candidate in wastewater treatment and remediating of heavy metals.

The potential of a natural biopolymeric flocculant, ε-poly-L-lysine, for harvesting Chlorella ellipsoidea and its sustainability perspectives for cost and toxicity.

The successful production of microalgal biomass requires the precise coordination of many different steps. Cell harvesting is a central process in all methods currently used for the production of microalgal biomass. Therefore, improving the harvesting process itself, and using a harvesting method that is compatible with adjacent steps, is necessary to prevent problems that may occur during downstream processing. This study examined the potential of the cationic biopolymer ε-poly-L-lysine (ε-PLL) for use in the harvest of microalgae (Chlorella ellipsoidea). The effects of ε-PLL concentration and mixing intensity on flocculation efficiency and operating costs were determined. We found that ε-PLL was not toxic to microalgal cells at concentrations of up to 25mg/L, based on the photosystem II quantum yield. A recovery rate of 95% was achieved using 19mg/L ε-PLL, and the estimated harvest cost was 20 US$/ton of harvested biomass. Moreover, ε-PLL displayed antimicrobial properties, leaving the harvested biomass intact and pure. Therefore, the use of ε-PLL-induced flocculation appears to be an attractive option when harvesting microalgal biomass for use as low- and high-value commodities for humans or animals.

Flocculating performance of a bioflocculant produced by Arthrobacter humicola in sewage waste water treatment

BackgroundThe discharge of poorly treated effluents into the environment has far reaching, consequential impacts on human and aquatic life forms. Thus, we evaluated the flocculating efficiency of our test bioflocculant and we report for the first time the ability of the biopolymeric flocculant produced by Arthrobacter humicola in the treatment of sewage wastewater. This strain was isolated from sediment soil sample at Sterkfontein dam in the Eastern Free State province of South Africa.ResultsBasic Local Alignment Search Tool (BLAST) analysis of the nucleotide sequence of the 16S rDNA revealed the bacteria to have 99% similarity to Arthrobacter humicola strain R1 and the sequence was deposited in the Gene bank as Arthrobacter humicola with accession number KC816574.1. Flocculating activity was enhanced with the aid of divalent cations, pH 12, at a dosage concentration of 0.8 mg/mL. The purified bioflocculant was heat stable and could retain more than 78% of its flocculating activity after heating at 100 °C for 25 min. Fourier Transform Infrared Spectroscopy analysis demonstrated the presence of hydroxyl and carboxyl moieties as the functional groups. The thermogravimetric analysis was used to monitor the pyrolysis profile of the purified bioflocculant and elemental composition revealed C: O: Na: P: K with 13.90: 41.96: 26.79: 16.61: 0.74 weight percentage respectively. The purified bioflocculant was able to remove chemical oxygen demand, biological oxygen demand, suspended solids, nitrate and turbidity from sewage waste water at efficiencies of 65.7%, 63.5%, 55.7%, 71.4% and 81.3% respectively.ConclusionsThe results of this study indicate the possibility of using the bioflocculant produced by Arthrobacter humicola as a potential alternative to synthesized chemical flocculants in sewage waste water treatment and other industrial waste water.

Biopolymeric flocculant extracted from potato residues using alkaline extraction method and its application in removing coal fly ash from ash-flushing wastewater generated from coal fired power plant

Ash-flushing wastewater generated by coal fired power plant generally contains high massive suspended coal fly ashes, which limit the recycling of ash-flushing wastewater and contaminate the environment due to the release of heavy metals from coal fly ashes. In this study, the Biopolymeric Flocculant extracted from Potato Residues (BFPR) under alkaline condition was applied to treat ash-flushing wastewater. The extraction conditions were optimized. The results showed that the highest yield of 58.77% BFPR was extracted from potato residues under the optimum condition: temperature 100 °C, potato residue concentration 42.09 g/L, extraction time 25.27 min, NaOH concentration 0.48 M and MgSO4•7H2O concentration 0.4 g/L. Gel permeation chromatography analysis indicated that the approximate molecular weight (MW) of BFPR was 4781 kDa. Fourier transform infrared spectroscopy indicated the presence of carboxyl, hydroxyl, and methoxyl groups in BFPR. Furthermore, BFPR showed good flocculating efficiency of 93.44% to ash-flushing wastewater when 8.3 mg/L BFPR was added, and thus achieved the recycling of ash-flushing wastewater.

Extraction, characterization and application of malva nut gum in water treatment.

In view of green developments in water treatment, plant-based flocculants have become the focus due to their safety, degradation and renewable properties. In addition, cost and energy-saving processes are preferable. In this study, malva nut gum (MNG), a new plant-based flocculant, and its composite with Fe in water treatment using single mode mixing are demonstrated. The result presents a simplified extraction of the MNG process. MNG has a high molecular weight of 2.3 × 10⁵ kDa and a high negative charge of -58.7 mV. From the results, it is a strong anionic flocculant. Moreover, it is observed to have a branch-like surface structure. Therefore, it conforms to the surface of particles well and exhibits good performance in water treatment. In water treatment, the Fe-MNG composite treats water at pH 3.01 and requires a low concentration of Fe and MNG of 0.08 and 0.06 mg/L, respectively, when added to the system. It is concluded that for a single-stage flocculation process, physico-chemical properties such as molecular weight, charge of polymer, surface morphology, pH, concentration of cation and concentration of biopolymeric flocculant affect the flocculating performance.

Antimicrobial efficacy and in vivo toxicity studies of a quaternized biopolymeric flocculant.

This study evaluated the antibacterial spectrum and safety of a chemically modified biopolymeric flocculant (TMB) against waterborne pathogens. The biopolymer previously characterized as polysaccharide with flocculating activity is produced extracellularly by the bacterium Klebsiella terrigena. The amino sugars on the polymer were chemically modified by quaternization, which resulted in N,N,N trimethyl biopolymer (TMB). Quaternization was effective in imparting biocidal activity to TMB against five selected waterborne pathogens, namely, Aeromonas hydrophila, Yersinia enterocolitica, Salmonella typhimurium, Listeria monocytogenes and Escherichia coli O157:H7. 99.999% inactivation was achieved with S. typhimurium at a dose of 60 μg ml(-1) of TMB within 60 min at the ambient temperature, followed by other pathogens. Haemotological, histopathological and general examinations indicated no adverse effects in Swiss albino mice fed with the quaternized biopolymer (120 mg kg(-1) body weight(-1) day(-1)) over a period of 30 days. These results suggested that TMB was tolerated well without any signs of toxicity and may have potential application as a safe, antimicrobial bioflocculant for both removing and inactivating waterborne pathogens.

Synthesis and evaluation of antibacterial activity of quaternized biopolymer from Klebsiella terrigena

Microbial exopolymer with antimicrobial properties, in particular, has gathered considerable interest due to their enormous scope of modification and wide gamut of application. The purpose of present study was to evaluate the antibacterial spectrum of a chemically modified biopolymeric flocculant produced by Klebsiella terrigena. N,N,N trimethyl biopolymer (TMB) was synthesized using dimethyl sulfate as methylating agent and was characterized by nuclear magnetic resonance and mass spectroscopic analysis, which confirmed the presence of quaternary ammonium groups on the TMB structure. The antibacterial activity of TMB was investigated against three selected bacterial pathogens viz. Aeromonas hydrophila ATCC 35654, Listeria monocytogenes ATCC 19111 and Escherichia coli O157:H7 ATCC 32150. An inactivation of 3logCFUml(-1) of all pathogens was noticed for TMB when compared to native polymer over a short contact time (60min) and low dosage (60-80μgml(-1) ) at ambient temperature. A marked increase in glucose level, protein content and lactate dehydrogenase (LDH) activity was observed concurrently in the cell supernatant suggesting damage of the cell membranes to be a possible reason for inactivation. The quaternization of amino rich biopolymer isolated from a bacterium led to a water-soluble bioactive agent with enhanced inhibitive capability against all the selected bacterial pathogens. The results of this study suggest a potential application of TMB as an effective disinfectant in water treatment.

Rapid inactivation of Salmonella by a quaternized biopolymeric flocculant

We report the characteristics and biocidal properties of a biopolymeric flocculant produced by Klebsiella terrigena capable of flocculating Salmonella efficiently from water. In order to impart an antimicrobial function, the native biopolymer was quaternized and the trimethyl biopolymeric derivative (TMB) was analysed physically, chemically and for flocculating properties. The quaternized biopolymer was evaluated for antimicrobial effects against four strains of Salmonella namely, S. typhimurium ATCC 23564, MTCC 1251, MTCC 98 and S. typhi MTCC 733. TMB did not differ significantly (p < 0.05) in either chemical and physical properties or flocculating ability when compared to its native counterpart. TMB completely inactivated Salmonella (60 μg/mL, at ambient temperature) within 60 min of exposure. Cell injury and death were evidenced by rapid increase in electrical conductivity in the media and release of intracellular alkaline phosphatase and glucose-6-phosphate dehydrogenases indicating permeation of cells. Electron micrographs revealed grossly altered morphology suggesting damage to the cell membranes as a possible reason for inactivation. The results of this study suggest a potential application of the developed biocidal bioflocculant for water treatment.

Characterization of a bioflocculant MBF-5 by Klebsiella pneumoniae and its application in Acanthamoeba cysts removal

This study evaluated the potential of an extracellular, novel biopolymeric flocculant produced by a strain of Klebsiella pneumoniae isolated from a sputum sample for removal of Acanthamoeba cysts, a potent pathogen prevalent in water, soil, air, and dust. The presence of cations did not enhance flocculating activity. The component of MBF-5 was mainly polysaccharide and protein with proportional of 96.8% and 2.1% respectively. Infrared spectrum analysis showed the presence of carboxyl and hydroxyl groups in MBF-5. MBF-5 is nontoxic and can be used for removal of amoebae cysts from water. Conditions for flocculation of kaolin suspension and Acanthamoeba cysts were optimized by response surface methodology (RSM) and determined to be 54.38 mg/L dosage, 26.14°C and pH 3.32 and 129.73 mg/L dosage, 30.75°C and pH 4.36, respectively. The results of this study indicates a possible use of the K. pneumoniae biopolymer as an alternative to typically used chemical flocculants for removal of amoebae cysts from water.

Reuse of Fruit Waste as Biopolymeric Flocculant and Optimizing Turbidity Reduction: Comparison Study with Industrial Flocculant

The performance of two flocculants on turbidity reduction was studied. The two flocculants were: a biopolymeric flocculant which was extracted from fruit waste and a commercial industrial flocculant. The effect of the flocculants’ average molecular weight on turbidity treatment, the treatment efficiency of both flocculants and the flocculants’ degradability were investigated. Response surface methodology was carried out using Box Behnken design to find the optimal pH, cation concentration, and flocculant dosage to maximize the turbidity reduction. The results showed that the maximum turbidity reduction by industrial flocculant occurs between pH 7.5 and pH 8.2, cation concentration between 0.02 and 0.06 mM, and industrial flocculant dosage between 6.5 and 8.0 mg/L. While with biopolymeric flocculant, maximum turbidity reduction occurred between pH 4.6 and pH 7.5, cation concentration between 0.60 and 0.95 mM, and biopolymeric flocculant dosage between 4 and 6 mg/L.

Characterization of biopolymeric flocculant (pectin) and organic synthetic flocculant (PAM): A comparative study on treatment and optimization in kaolin suspension

Polyacrylamide (PAM), a commonly used organic synthetic flocculant, is known to have high reduction in turbidity treatment. However, PAM is not readily degradable. In this paper, pectin as a biopolymeric flocculant is used. The objectives are (i) to determine the characteristics of both flocculants (ii) to optimize the treatment processes of both flocculants in synthetic turbid waste water. The results obtained indicated that pectin has a lower average molecular weight at 1.63 × 10 5 and PAM at 6.00 × 10 7. However, the thermal degradation results showed that the onset temperature for pectin is at 165.58 °C, while the highest onset temperature obtained for PAM is at 235.39 °C. The optimum treatment conditions for the biopolymeric flocculant for flocculating activity was at pH 3, cation concentration at 0.55 mM, and pectin concentration at 3 mg/L. In contrast, PAM was at pH 4, cation concentration >0.05 mM and PAM concentration between 13 and 30 mg/L.

Application of a novel biopolymer for removal of Salmonella from poultry wastewater

This study evaluated the potential of an extracellular, novel biopolymeric flocculant produced by a strain of Klebsiella terrigena for removal of Salmonella, a potent pathogen prevalent in poultry wastewater. The purified biopolymer was applied to poultry wastewater containing 3 log CFU cells of Salmonella. An optimized dosage of 2 mg L−1of the purified bioflocculant was sufficient to remove 80.3% Salmonella spp. within 30 min, at ambient temperature. Also this bioflocculant showed high flocculating activity (90%) against kaolin particles and proved to be far more effective than the other synthetic flocculants used in this study. Fluorescent in situ hybridization (FISH) with the genus specific Sal3 probe hybridized with the Salmonella present in the agglomerated matrix of the bioflocculant. Confocal laser scanning micrographs (CLSM) allowed a clear visualization of the spatial distribution of the total flocculated bacterial population (with DAPI and Eub338 probe) as well as Salmonella (with the Sal3 probe), indicating that the removed Salmonella remained bound and embedded within the flocculant matrix. Scanning electron microscopic (SEM) analysis exhibited a porous surface morphology. The bioflocculant was characterized to be a polysaccharide by FTIR, HPLC, CHN and chemical analysis. A viable alternative treatment technology of poultry wastewater using this novel bioflocculant is suggested.