Bioflocculants Produced by Bacterial Strains Isolated from Palm Oil Mill Effluent for Application in the Removal of Eriochrome Black T Dye from Water

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.

A novel bioflocculant for chromium (Ⅵ) and arsenic (Ⅲ) removal: Extracellular polymeric substance (EPS) of Pseudomonas fluorescens

<p>Bioflocculants produced by microorganisms have advantages in removing heavy metals because of their environmental friendliness and biodegradability. In this study, the bioflocculant from a soil bacteria was investigated for its application in chromium (Ⅵ) and arsenic (Ⅲ) removal. The bioflocculant-producing strain was indentified as Pseudomonas fluorescens. It showed maximum flocculating activity of 2579.94 U/mL and yield of 4.84 g/L under optimal condition. With a fed‑batch fermentation strategy, bioflocculant production was further enhanced by 32.6%. The bioflocculant was as extracellular polymer substance composed of 76.67% polysaccharides and 15.8% protein with a molecular weight of 117 kDa. It showed excellent capacities in heavy metal removal, 80.13 and 45.93 mg/g for chromium(Ⅵ) and arsenic (Ⅲ), respectively. The bioflocculant outperformed conventional adsorption materials and could represent a promising biotechnology for the remediation of environmental problems.</p>

Optimization of the flocculating capacity of natural coagulants in water treatment

The objective was optimize the flocculating capacity of three varities of cacti Echinopsis pachanoi (San Pedro), Neoraimondia arequipenses (Ulluquite) and Opuntia ficus (Tuna) in the artificial wastewater treatment. They were applied 1%, 2% and 3% coagulant doses of the three varieties of cactaceae extracted with 96% ethanol. It was evaluated the flocculating activity (FA) and removal percentage (%R); a significant increase was observed (p-value < 0.05) with the increase in the coagulant dose. The optimization was carried out considering as objective function the %R which were subjected to FA, pH, hardness, alkalinity and BOD5 of water treatment. Which were reported values of 99.09 %R for San Pedro variety, 92.42 %R for Ulluquite variety and 98.98 %R for tuna variety, for doses of 0.207%, 0.246% and 0.754% of coagulant respectively.

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.

Flocculating Properties of a Bioflocculant Purified from Bacillus Subtilis Isolated from the Stream Sediments of Onyearugbulem Market, Akure, Nigeria

Soil samples (sediments of stream, its bank and abattoir soil) were collected from Onyearugbulem market abattoir, Akure, Ondo State, Nigeria. Bacteria were isolated from the above soil samples by dilution and pour plate methods. Screening for best bioflocculating bacteria was also performed. Effects of metal ions (such as Mg2+, Ca2+ and Al3+), temperature and pH on flocculating activities of the bioflocculant were also determined. Six bacterial isolates producing flocculating substances were isolated and the isolate with the best flocculating property was selected. The identified bioflocculant producing bacteria are Bacillus anthracis, B. subtilis, B. thuringiensis, B. cereus, Streptomyces griseus and S. somaliensis. The best bioflocculant producing bacterium was Bacillus subtilis and the flocculating activity of its bioflocculant was stimulated in the presence of Mg2+, Ca2+and Al3+. This bioflocculant was thermostable and retained more than 80% of its flocculating activity after being heated at 100ºC for 25 minutes. It had the highest flocculating activity of 85% at pH 6 with optimum bioflocculant dosage of 0.8 mL. This study suggests soil samples from Onyearugbulem market abattoir as a potential source of bioflocculant-producing bacteria with good bioflocculating properties.

Characterisation of Fungal Bioflocculants and Its Application in Water Treatment

Bioflocculants of microbial origin have the advantage of being safe, biodegradable and harmless to the environment. Production of bioflocculant by two fungi isolates and the factors affecting its production were investigated in this study. Primary screening of fungi for the production of bioflocculants, efficiencies and conditions for the optimum production of the bioflocculants were determined using standard microbiological and chemical methods. Aspergillus flavus MCB 271 and Aspergillus niger MCBF 08 were the best bioflocculant producers among the fourteen fungal isolates screened. Aspergillus flavus optimally produced bioflocculant with glucose and peptone as sole carbon and nitrogen sources respectively. Calcium ions (Ca2+) at 78.4% served as best cation sources for bioflocculant production with optimal pH of 7 and temperature of 40°C. Aspergillus niger MCBF 08 produced bioflocculant optimally when the media had peptone as a nitrogen source and maltose as a sole carbon source. The two species achieved the maximum flocculating activity of 97% (A. flavus MCBF 271) and 86% (A. niger MCBF 08) at pH values of 7 on the 3rd day of the study and caused a reduction in bacterial load of the wastewater samples by 58.73% and 60.85% respectively. These bioflocculants are thus potential replacement for synthetic flocculants conventionally used for wastewater treatment.

Assessment of the flocculating potentials of Alcaligenes faecalis Isolated from the Estuary of Sodwana Bay

Alcaligenes faecaliswas previously isolated from Sodwana Bay, South Africa and was shown to be a bioflocculant producing microorganism. The bioflocculant production potential was further assessed through the optimization of the standardized culture media. The production of biofloculant as well as the flocculation was evaluated using different variables such as the size of inoculum, sources of carbon and nitrogen, time course and pH. Through optimizationA. faecalisshowed an improvement in the production of its bioflocculant and also flocculating activity for the following factors: flocculating activity of 71% for an inoculum size of 1%. The bioflocculant produced when maltose was used as source of carbon, showed flocculating activity of 91%, urea, as the most efficient nitrogen source, showed a flocculating activity of 97%, the optimum pH was 9. The time courses analysis between 60 and 72 hours showed the peak for flocculation and by implication highest level of bioflocculant production.

Microbial Flocculants as an Alternative to Synthetic Polymers for Wastewater Treatment: A Review

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.

Production and Characterization of a Bioflocculant Produced by Bacillus salmalaya 139SI-7 and Its Applications in Wastewater Treatment

The production, optimization, and characterization of the bioflocculant QZ-7 synthesized by a novel Bacillus salmalaya strain 139SI isolated from a private farm soil in Selangor, Malaysia, are reported. The flocculating activity of bioflocculant QZ-7 present in the selected strain was found to be 83.3%. The optimal culture for flocculant production was achieved after cultivation at 35.5 °C for 72 h at pH 7 ± 0.2, with an inoculum size of 5% (v/v) and sucrose and yeast extract as carbon and nitrogen sources. The maximum flocculating activity was found to be 92.6%. Chemical analysis revealed that the pure bioflocculant consisted of 79.08% carbohydrates and 15.4% proteins. The average molecular weight of the bioflocculant was calculated to be 5.13 × 105 Da. Infrared spectrometric analysis showed the presence of carboxyl (COO-), hydroxyl (-OH), and amino (-NH2) groups, polysaccharides and proteins. The bioflocculant QZ-7 exhibited a wide pH stability range from 4 to 7, with a flocculation activity of 85% at pH 7 ± 0.2. In addition, QZ-7 was thermally stable and retained more than 80% of its flocculating activity after being heated at 80 °C for 30 min. SEM analysis revealed that QZ-7 exhibited a clear crystalline brick-shaped structure. After treating wastewater, the bioflocculant QZ-7 showed significant flocculation performance with a COD removal efficiency of 93%, whereas a BOD removal efficiency of 92.4% was observed in the B. salmalaya strain 139SI. These values indicate the promising applications of the bioflocculant QZ-7 in wastewater treatment.

Screening for Bioflocculant-Producing Bacteria from the Marine Environment of Sodwana Bay, South Africa

Flocculants 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.