EC Microbiology

Biosurfactants are amphipathic biomolecules produced by biological entities with vast applications. Waste water from a dairy processing industry showed maximum microbial heterotrophic activity; physicochemical analysis of the waste water showed the presence of the following: Cl, Ca, Mg, PO^2-₃, K as dissolved mineral contents. Heavy metals analysis showed the presence of Pb in trace concentration while Cu and Fe were richly in abundance. Physical properties of the waste water showed a relatively acidic pH of 6.0, conductivity of 893Ω^-1cm^-1 while solid contents such as TS, TDS and TSS were found as 1341, 580.45 and 760.55 g/l. initial oxygen concentration (mg/l) of the waste water was 6.23 mg/l while after five days the BOD quotient was 4.32 mg/l. Strains of E.coli, Salmonella sp., Yesinia sp., Vibrio sp., Bacillus sp., Pseudomonas sp., Klebsiella sp., were found after isolation using standard microbiology and biochemical techniques. Microbial load and standardization of the isolates were done using the Marcfarland solution, total heterotrophic number of the organisms (CFU/ml) showed the following: E. coli 3.2 x 10⁵, Salmonella sp 3.0 x 10⁵, Yesinia sp 2.2 x 10⁴, Bacillus sp 3.8 x 10⁶, Pseudomonas sp 3.7 x 10⁶ and Klebsiella sp. 3.2 x 10⁶. Emulsification assessment (emulsification index) of the organisms in the presence of crude oil only showed the following: E. coli 54.3%, Salmonella sp 43.51%, Yesinia sp 38.72%, Bacillus sp 56.21%, Pseudomonas sp 64.32% and Klebsiella sp. 62.31%. The same trend was seen in the presence of olive oil and coconut oil with Pseudomonas sp 67.3% and Klebsiella sp 71.09% showing the highest index of emulsification. Further investigation of emulsification potentials using oil drop collapse and spread plate techniques still showed optimized peak emulsification of strains of Pseudomonas sp. and Klebsiella sp in the presence of different oil used: kerosene, crude oil (bonny light), coconut oil and olive oil. The two consortiums were used for biosurfactant production in a submerged fermentation system.

 Keywords: Biosurfactants; Emulsification; Microbial Load; Physicochemical; Oil

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