Scale up studies for the production of biosurfactant in packed column bioreactor

Abstract

Biosurfactants capable of emulsifying pesticides have great potential to assist in microbial degradation of the pesticides. Solid State Fermentation (SSF) due to several advantages, is one of the efficient ways of producing these surfactants and seldom receives attention for commercial exploitation. In this study, a packed column bioreactor with wheat bran as the raw material and Bacillus subtilis has been used to produce a biosurfactant specific to disperse Fenthion, an organophosphrous pesticide. The emulsifier activity (EA) and surface tension from the packed column bioreactor were compared with flask fermentation experiments, which served as control. Airflow rate in the packed column bioreactor was varied from 10–20 l/min. Maximum EA and minimum surface tension occurred at airflow rate of 20 l/min. Peak EA in the control was 1.2 at 29 h while it was 1.9 in the bioreactor. The least surface tension of 24 dynes/cm was noticed at 54 h in the bioreactor, which was 33% better than the control at the same time period. The results indicate that the packed column bioreactor can become a more acceptable solid state fermentation system for commercial exploitation of Fenthion specific biosurfactant production.