Evaluation of Indigenous Kluyveromyces marxianus Isolated from Western Himalayan Region of Himachal Pradesh as a Potential Source of Exopolysaccharide Production.

Response surface methodology (RSM) was used in this study to optimize the fermentation conditions for exopolysaccharides (EPSs) produced by Kluyveromyces marxianus Y72. The results showed that, under the optimal fermentation conditions, K. marxianus Y72 produced mucoid ropy white colonies on ruthenium red skimmed milk agar. Optimal exopolysaccharide production was achieved after 72 h, pH 6.5 and agitation rate 200 rpm with yield of 0.286 ± 0.002 g/L using banana peel extract as a carbohydrate source. The optimal incubation temperature of 25 ˚C showed maximum EPS yield of 0.309±0.005 g/L. Thirty validator runs were carried out using the central composite design (CCD) for the response surface methodology (RSM), which included, carbon concentration, temperature, incubation time, and agitation from one variable at a time (OVAT). EPS was dialysed with 24 kDa membrane for 24 h and the dialyzed EPS was then precipitated with chilled ethanol. By employing the DPPH assay to test the antioxidant activity of crude EPS, 60% activity was achieved, and 74.05% activity was achieved using partially purified EPS at the same concentration of EPS. In crude EPS isolated from K. marxianus Y72, cholesterol adsorption of 64.70% was observed. Antimicrobial activity was also checked against Escherichia coli, Salmonella typhi, Bacillus cereus, Pseudomonas aeruginosa, and Staphylococcus aureus showed negative findings. [ABSTRACT FROM AUTHOR]