Process optimization and production of polyhydroxybutyrate using palm jaggery as economical carbon source by marine sponge-associated Bacillus licheniformis MSBN12

The Polyhydroxybutyrate (PHB) producer, Bacillus licheniformis MSBN12 was isolated from the marine sponge Callyspongia diffusa. The PHB production of B. licheniformis MSBN12 was optimized using a four-factor Box-Behnken design to find the interactive effects of variables such as palm jaggery, wheat bran, seawater, and incubation temperature. The maximum yield of PHB (6.38 g/L) was achieved through response surface methodology-based optimization and the optimized conditions were further used for the batch and fed-batch fermentation. Maximum biomass was reached at 48 and 36 h of incubation with PHB accumulation of 62.91 and 67.16 % (w/w of dry cells) for batch and fed-batch process. The production of PHB under fed-batch process with B. licheniformis MSBN12 was increased threefold over shake flask culture when palm jaggery as sole carbon source. The A(1)H NMR data was extrapolated with peaks of the PHB reference standard and confirmed as PHB analog.