Poly--hydroxybutyrate production by Pseudomonas sp. RZS 1 under aerobic and semi-aerobic condition.

ABSTRACT

Pseudomonas sp. RZS1 was isolated from distillery effluent and identified based on phenotypic characters and 16s rRNA sequencing. It accumulated optimum amount (703.79 g/mg of biomass) of poly--hydroxybutyrate (PHB) under aerobic process of fermentation and 75 g/mg of biomass under the anaerobic process of fermentation. Aerobic fermentation yielded 9.3-fold more PHB than semi-aerobic fermentation. Acetone alcohol method proved to be the best suitable recovery method as it gave 703.79 g PHB per mg of biomass with a percentage recovery yield of 70.37. It started to accumulate PHB at the end of lag phase (from 6 h of incubation). Optimum amount of PHB (20 g/ml) was reported during early stationary phase (30 h of incubation). Extracted PHB showed two peaks, minor one at 248 nm and major one at 365 nm. IR spectra revealed the presence of functional groups characteristics of PHB.