Bioprocess development for utilizing biodiesel industry generated crude glycerol for production of poly-3-hydroxybutyrate

Abstract

This study presents <i>Bacillus firmus </i>NII 0830 for producing poly-3-hydroxybutyrate (PHB) using biodiesel industry generated glycerol, a waste by-product, as sole carbon source under submerged fermentation and production process was optimized using statistical experimental design. PHB accumulation was observed up to 1.60 g/l from 4.36 g/l of total bacterial biomass at inoculum size of 3% v/v, incubation temperature 30°C, crude glycerol concentration 5% v/v, 250 RPM, incubation time 60 h and media pH 6.0 during initial statistical design. Further Response Surface design experiments yielded 61% of PHB from <i>B. firmus </i>NII 0830. Glycerol has a low market price and it does not require any further refinement, makes present process more economical. Further, utilization of low-grade waste glycerol solves its disposal problem, hence it is aptly an environmentally friendly ‘waste to wealth’ bioprocess.