Polyhydroxybutyrate production from ultrasound-aided alkaline pretreated finger millet straw using Bacillus megaterium strain CAM12

In this study, finger millet straw (FMS) was utilized for the production of Polyhydroxybutyrate (PHB) by Bacillus megaterium strain CAM12. Ultrasound-assisted alkaline (NaOH) pretreatment of FMS under optimized conditions followed by enzymatic saccharification resulted in the maximum delignification (72%), hydrolysis yield (84%), glucose yield (86%) and xylose yield (61%). The effects of different pH, temperature, incubation period, inoculum concentration, agitation speed and FMS enzymatic hydmlysates concentration were investigated to improve the PHB production. Under optimized conditions, strain CAM12 used the FMS hydrolysates as the sole carbon source for their growth and produced 8.31 g L-1 of PHB. The extracted polymer on Fourier transform infrared (FTIR), X-ray diffraction (XRD) and Nuclear magnetic resonance (NMR) analyses were confirmed to be PHB. These results suggest the potential of combined ultrasound and alkaline pretreated FMS hydrolysates as a promising feedstock for PHB production.

Automated summary

In this study, finger millet straw (FMS) was utilized for the production of Polyhydroxybutyrate (PHB) by Bacillus megaterium strain CAM12. The combination of ultrasound-assisted alkaline pretreatment and enzymatic saccharification of FMS resulted in high delignification and hydrolysis yields, leading to successful PHB production by the strain CAM12. The extracted polymer was confirmed to be PHB through analytical techniques like FTIR, XRD, and NMR, highlighting the potential of FMS hydrolysates as a promising feedstock for PHB production.