Biosynthesis and characterization of poly (3-hydroxybutyrate-co-3- hydroxyvalerate) from Bacillus cereus FA11 isolated from TNT-contaminated soil

Abstract

In the present study, a poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [poly(3HB-co-3HV)]-producing bacterial strain was isolated from trinitrotoluene (TNT)-contaminated soil using Sudan black B and Nile blue A staining as a screening method. The bacterial strain was identified as Bacillus cereus FA11 on the basis of biochemical tests and 16S rRNA sequencing. Culture conditions, such as pH, temperature, time and carbon sources, were optimized for maximum production of the copolymer. B. cereus FA11 was found capable of producing a maximum of 48.43% poly (3HB-co-3HV) at pH 7, with glucose as the carbon source, after 48 h of incubation at 30°C. Fourier transform infrared analysis of the extracted polymer revealed similarities in the spectra of the microbial and commercially available poly (3HB-co-3HV) at 1720.2, 1278.5 and 2932.1 cm -1 wavelength. 1H-nuclear magnetic resonance analysis of the polymer confirmed it as a copolymer composed of 3-hydroxybutyrate and 3-hydroxyvalerate monomeric units. © 2012 Springer-Verlag and the University of Milan.