Media engineering for production of poly-<img src='/image/spc_char/beta.gif' border=0>-hydroxybutyrate by <i>Bacillus</i> <i>firmus </i>NII 0830

Abstract

This study evaluates biodiesel industry generated crude glycerol as sole carbon source for the production of poly-<img src='/image/spc_char/beta.gif' border=0>-hydroxybutyrate (PHB) using <i>Bacillus firmus </i>NII 0830. Pretreatment of crude glycerol from biodiesel industry was tried using

strong acids. Biomass yield and PHB accumulation by <i>B. firmus </i>NII 0830 in submerged fermentation was compared using crude

as well as pretreated glycerol as sole carbon source. It was observed that crude glycerol from biodiesel industry, without any

pretreatment, can be used for PHB production. The organism when grown in mineral salt media containing crude glycerol as carbon

source gave a maximum yield of biomass (3 g/l) and PHB (53% of cell dry wt). Response surface methodology (RSM) showed that

presence of nitrogen and phosphate in fermentation media favored biomass production but reduced PHB production. Optimized

crude glycerol media for maximum PHB accumulation contains ammonium sulphate (4 g/l) and K2HPO4 (0.8 g/l).