Influence of molasses on the growth and polyhydroxybutyrate accumulation of native bacteria isolated in Ho Chi Minh city

Abstract

In this research, the authors evaluated the PHB biosynthesis and the effect of molasses on growth and PHB accumulation of the three bacterial strains which had been previously isolated: Pseudomonas stutzeri strain H6, Enterobacter cloacae strain H61 and Bacillus sp. strain H37. The results showed that molasses at concentration of 20 g/l was less effective than at 40 g/l in inducing PHB accumulation. However, raising the concentration to 60 g/l conferred the inhibitory effect on the PHB biosynthesis of the strains in this study. The Bacillus sp. strain H37 accumulated 86% (w/w) PHB at 40 g/l molasses after 48 hours of incubation. Enterobacter cloacae strain H61 also produced 85.6% (w/w) PHB at the same molasses concentration and incubation time. Meanwhile, Pseudomonas stutzeri strain H6 surpassed the above two strains to produce 82% (w/w) PHB at 40 g/l of molasses within 28 hours of incubation. Alcaligenes sp. was used in this experiment as the control strain.