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.

Hydrogen and Polyhydroxybutyrate Producing Abilities of Bacillus spp. From Glucose in Two Stage System

“…In our present work and previous reports [11], H 2 evolution was found to follow a pattern with respect to drop in pH (higher pH drop leading to higher H 2 production). Acidification activates formate dehydrogenase and pyruvate formatelyase system leading to H 2 generation [3:5] via formate accompanied by the release of acetyl CoA [13,31], which may be subsequently diverted towards PHB production, depending upon environmental (nutritional) stress [4,32].…”

Agro-industrial residues and starch for growth and co-production of polyhydroxyalkanoate copolymer and α-amylase by Bacillus sp. CFR-67

“…are known to produce PHA (6,18,31,38) and they also produce -amylase extracellularly, which has several commercial applications (2,12). Present study is the first attempt to produce -amylase and PHA-copolymer simultaneously by Bacillus sp.…”

Utilization of palm oil mill effluent for polyhydroxyalkanoate production and nutrient removal using statistical design

“…Also, a CCRD is employed for fitting the second-order polynomial because it is an economical way to obtain the maximum amount of information with the fewest number of experiments on mixing time or a dependent variable. An empirical equation in the form of a second-order polynomial was obtained with specified and limited data (Vijayendra et al 2007).…”