title: Optimization of polyhydroxybutyrate production by Bacillus sp. CFR 256 with corn steep liquor as a nitrogen source.
abstract: Polyhydroxyalkanotes (PHAs), the eco-friendly biopolymers produced by many bacteria, are gaining importance in curtailing the environmental pollution by replacing the non-biodegradable plastics derived from petroleum. The present study was carried out to economize the polyhydroxybutyrate (PHB) production by optimizing the fermentation medium using corn steep liquor (CSL), a by-product of starch processing industry, as a cheap nitrogen source, by Bacillus sp. CFR 256. Response surface methodology (RSM) was used to optimize the fermentation medium using the variables such as corn steep liquor (5-25 g l(-1)), Na(2)HPO(4) 2H(2)O (2.2-6.2 g l(-1)), KH(2)PO(4) (0.5-2.5 g l(-1)), sucrose (5-55 g l(-1)) and inoculum concentration (1-25 ml l(-1)). Central composite rotatable design (CCRD) experiments were carried out to study the complex interactions of the variables.The optimum conditions for maximum PHB production were (g l(-1)): CSL-25, Na(2)HPO(4) 2H(2)O-2.2, KH(2)PO(4) - 0.5, sucrose - 55 and inoculum - 10 (ml l(-1)). After 72 h of fermentation, the amount of PHA produced was 8.20 g l(-1) (51.20% of dry cell biomass). It is the first report on optimization of fermentation medium using CSL as a nitrogen source, for PHB production by Bacillus sp.
authors.affiliation: Department of Food Microbiology, Central Food Technological Research Institute, Mysore, 570 020 India.
authors.forename: S V N
authors.initials: SV
authors.lastname: Vijayendra
authors.forename: N K
authors.initials: NK
authors.lastname: Rastogi
authors.forename: T R
authors.initials: TR
authors.lastname: Shamala
authors.forename: P K
authors.initials: PK
authors.lastname: Anil Kumar
authors.forename: L
authors.initials: L
authors.lastname: Kshama
authors.forename: G J
authors.initials: GJ
authors.lastname: Joshi
keywords: Bacillus; Central composite rotatable design; Corn steep liquor; Optimization; Polyhydroxybutyrate; Response surface methodology