Optimization of bacterial polyhydroxyalkanoate production by using one-factor-at-a-time approach

Scale Up Studies for Polyhydroxyalkanoate Production by a Bacillus flexus Strain with Industrial Potential

“…Furthermore, co-polymer production by Bacillus sp., from simple sugars has been reported in presence of supplemented precursors [3,6]. The work presented here is an attempt to develop a fermentation process without exogenously adding of precursors, for production of PHA by indigenously isolated B. flexus MTCC 12841 strain [7] using a laboratory fermentor. The biopolymer thus produced was characterized by GC-MS.…”

“…Bacillus flexus MTCC 12841 (B. flexus DYC3) isolated from a dumping yard from Mumbai, India was selected for scale up studies [7]. B lite Sartorius lab fermentor (6.6 L geometric volume) with pH and DO probes and having Supervisory Control and Data Acquisition software (SCADA) was used.…”

“…The batch was inoculated with 5% actively growing 18-20 h old B. flexus LB broth seed culture (OD 620 = 0.75 ± 0.02). The temperature, pH, DO and agitation were monitored using SCADA whereas Dry Cell Weight (DCW) and PHA were determined offline by aseptically removing broth samples [3,7]. For GC-MS studies, dried biomass was derivatized by methanolysis [2] and analyzed on a Shimadzu GCMS-QP2010 Ultra, with SH-Rxi-5Sil MS column (30 m 9 0.25 mm 9 0.25 lm).…”

“…First batch reiterated the findings by Somashekara et al [9] that PHA production was growth associated for the strain. Apart from unbalanced medium composition, suboptimal growth temperature or insufficient mixing and oxygenation of the broth could have resulted in low yield [7,9]. The strategy to provide optimum temperature and aeration for first promoting good growth followed by optimum conditions for PHA production, led to a considerable increase in biomass in lesser time span in batch no.…”