Poly-3-hydroxyalkanoates production potential of Bacillus cereus C113 isolated from cassava dumpsite using some carbon sources

Abstract

Poly-3-hydroxyalkanoates (PHAs) are biopolymers accumulated as intracellular energy reserves by bacteria under nutrient limiting growth conditions and suitable for plastic production. We report findings from the use of a bacterium isolated from a cassava dumpsite for PHAs production. Isolate C113 was screened for PHAs production using the viable colony and Sudan Black B staining methods and further identified by 16SrRNA sequencing. Its PHA synthase gene, PhaR, was also partially amplified and sequenced. PHAs production was achieved over 96-hour incubation, extracted by NaClO/chloroform method and analysed by FT-IR. Isolate C113 was positive for PHA production in all carbon sources and was identified as a strain of Bacillus cereus. It showed highest biomass accumulation in glucose and starch. It achieved PHAs production of 4.85 % dry cell weight (DCW) in glucose, 33.03 %DCW in glycerol and 6.05 %DCW in sugarcane molasses at 24 hours while 10.58 %DCW was produced in starch at 96 hours. FT-IR spectra showed peaks corresponding to P3HB and P3HB3HV and reveal conformational changes of mcl-PHA and scl-PHA in crystalline and amorphous phases. The 16SrRNA (KY855372.1) and PhaR (MF947451.1) sequences have been accessioned in NCBIGenBank. The results show that Bacillus cereus C113 demonstrated capacity to utilize a variety of carbon sources for PHAs production.