Scale up and optimization of cholesterol oxidase production from Streptomyces rimosus MTCC 10792 in a 3-L bioreactor

Abstract

A scale-up approach was investigated for maximum production of cholesterol oxidase (CO) enzyme, due to its high demand in agricultural and pharmaceutical industries. The CO production from Streptomyces rimosus in submerged fermentation conditions at shake flask level was observed in yeast malt glucose (YMG) medium as 1.82 U/mL. Maximum specific growth rate (μmax) and generation time (g) in log phase of microbial growth were found as 0.107 h−1 and 6.46 h respectively. During the CO production in 3-L bioreactor, the optimum parameters were observed as agitation—200 rpm, aeration—1.5 vvm, pH—7.0 and temperature 30 °C, with maximum production (8.66 U/mL, yield 0.916 U/mg cells), which showed 4.75 fold increase as compared to shake-flask production (1.82 U/mL, yield 0.243 U/mg). The volumetric oxygen mass transfer rate (KLa) was found to be in the range of 16 h−1 by dynamic gassing out method under optimized aeration and agitation parameters. The production of CO from S. rimosus in bioreactor is not reported earlier.