A novel bioflocculant-producing bacteria was isolated from sediment samples of Algoa Bay in the Eastern Cape Province of South Africa and the effect of culture conditions on the bioflocculant production was investigated. Analysis of the partial nucleotide sequence of the 16S rDNA of the bacteria revealed 99% similarity to Cobetia sp. L222 and the sequence was deposited in GenBank as Cobetia sp. OAUIFE (accession number JF799092). Cultivation condition studies revealed that bioflocculant production was optimal with an inoculum size of 2% (v/v), initial pH of 6.0, Mn²⁺ as the metal ion, and glucose as the carbon source. Metal ions, including Na⁺, K⁺, Li⁺, Ca²⁺and Mg²⁺ stimulated bioflocculant production, resulting in flocculating activity of above 90%. This crude bioflocculant is thermally stable, with about 78% of its flocculating activity remaining after heating at 100 °C for 25 min. Analysis of the purified bioflocculant revealed it to be an acidic extracellular polysaccharide.

In our previous study we reported on the bioflocculant production by a Bacillus species isolated from sediment samples of Algoa Bay in the Eastern Cape Province of South Africa. In the current study we carried out further evaluation on the effect of different culture conditions on the bioflocculant production, as well as characterised the bioflocculant produced in detail. The bacteria produced bioflocculant optimally under the following conditions: using sodium carbonate (95.2% flocculating activity) and potassium nitrate (76.6% flocculating activity) as carbon and nitrogen sources, respectively; inoculum size of 3% (v/v); initial pH 9.0; and Al³⁺ as coagulant aid. The crude bioflocculant retained 44.2% residual flocculating activity after heating at 100°C for 15 min. Chemical analysis of the Bacillus sp. Gilbert purified bioflocculant demonstrated that it was composed mainly of polysaccharide. Fourier transform infrared spectroscopy analysis revealed the presence of hydroxyl, carboxyl and methylene groups in the bioflocculant and energy-dispersive X-ray analysis detected the elemental composition in mass proportion (% w/w) of C, N, O, S and P as 4.12:7.40:39.92:3.00:13.91. Scanning electron micrograph image of the bioflocculant revealed an amorphous compound.

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 as Pseudoalteromonas 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.

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.

One of the environmental determinants of health is the quality of drinking water, and water of good quality is void of impurities and pathogenic microbes. Poor quality water has deleterious effects on man's health and wholeness. Conducting a periodic evaluation to ascertain the likely water pollution in the environment is imperative. The study evaluated the physical-chemical parameters (pH, temperature, total dissolved solids, electrical conductivity, total Hardness, Calcium Hardness, Magnesium Hardness, salinity, appearance, odour, Sulphate, Nitrate, Carbonate and Bicarbonate, Sodium, Calcium, and Magnesium contents), heavy metals (Cadmium, Arsenic, and Lead) concentrations and bacterial qualities (total heterotrophic bacteria count and total coliform count) of groundwater from twelve (12) boreholes in four different locations in Etsako West Local Government Area. All the physicochemical indicators analyzed in this study were within the recommended standards except for pH, which is acidic. The heavy metal concentrations and the total heterotrophic bacterial count mean values surpassed the WHO permissible limits. The research identified six genera of bacteria: Klebsiella spp, Staphylococcus spp, Streptococcus spp, Neisseria spp, Enterococcus spp, and E. coli. This study shows that groundwater quality from different boreholes across the LGA is unsuitable for consumption due to toxic metal contamination and high bacteria load. Therefore, there is a need for proper treatment of the water from different borehole sources by boiling or chlorination before consumption. Key words: Contamination; drinking water; heavy metal; heterotrophic; physicochemical; quality

Borehole water remains one of the principal sources of drinking water in Etsako Central Local Government Area; therefore, it is very crucial to evaluate the quality of these various borehole water sources. This study is aimed at investigating the physicochemical parameters (pH, temperature, total dissolved solids, electrical conductivity, total hardness, Calcium hardness, Magnesium hardness, salinity, appearance, odour, Sulphate, Nitrate, Carbonate and Bicarbonate, Sodium, Calcium, and Magnesium contents, heavy metals (Cadmium, Arsenic and Lead) concentrations and bacteriological qualities (total heterotrophic bacteria count and total coliform count) of groundwater from twelve (12) boreholes in different locations in Edo North Senatorial District (Etsako West, Etsako Central, and Etsako East Local Government Areas). All parameters evaluated in-situ were done using standard methods in the laboratory. All physicochemical properties analyzed in this study complied with the recommended standards except for pH which is acidic. The heavy metal concentrations and the total heterotrophic bacterial count mean values exceeded the WHO permissible guideline value. Seven (7) genera of bacteria isolates namely; Enterococcus spp, Staphylococcus spp, Neisseria spp, Klebsiella spp, Yersinia pestis, E. coli, and Streptococcus spp were identified. This study reveals that the quality of groundwater from different boreholes across the Etsako Central Local Government Area is not fit for consumption due to the presence of increased levels of trace elements contaminations and high bacteria load. Therefore, it is recommended that adequate treatment of the water from different borehole sources by boiling or chlorination prior to consumption should be carried out.