Microbial Production of Biopolymers

Abstract

In this study, three bacterial strains were recovered from activated sewage sludge and Rubbish which were able to produce biopolymer, and these strains were identified biochemically and molecularly as Bacillus flexus strain AESK1, Bacillus megaterium SMSE1, and Bacillus iocasae strain mmas4.Plackett-Burman (PB) factorial design was used for the three bacterial isolates to screen the most favorable conditions to produce high PHA amount. The production was enhanced by the addition of ethanol 70%, hydrogen peroxide, or a mixture (1:1) of both. As a result of the enhancement step the PHA of Bacillus flexus strain AESK1, Bacillus megaterium SMSE1, and Bacillus iocasae strain mmas4 was increased by 2.5, 10.2, 3.3fold by the three respective strains when compared with their control tests. The extracted PHA was analyzed by Fourier transform infrared (FTIR) spectroscopy and 1H-NMR analysis, and the generated PHA was recognized as P (3HB-co-3-HV) co polyester (poly-3-hydroxy butyrate-poly-3-hydroxy valerate), and thermally analyzed by TGA and DTA and it was proved that the extracted PHA has thermal stability up to 200°C. The results indicated the ability to produce green plastics other than petrochemical ones using cheap production media containing molasses as inexpensive substrate.