Production and Characterization of Polyhydroxyalkanoates (PHAS) Produced from Bacillus Cereus MUL-A isolated from a Biogas Digester

Catégorie : Nouveaux Matériaux
Date :6 novembre 2020
Khan, Tahir Kamal; Ul Haq, Ikram; Nawaz, Ali; Mukhtar, Hamid.
Pakistan Journal of Botany : 52 (DocId: 6) 2175–2182.
Polyhydroxyalkanoic acids (PHA) are biodegradable polymers synthesized by microorganisms which can serve as alternative to conventional petrochemical based plastics. In the present study, twenty one bacterial isolates from one hundred & twenty six samples taken from anaerobic digester were screened for the PHA accumulation ability using Sudan Black B dye and further subjected to submerged fermentation to estimate the PHA production by maximum PHAs yielding strain. By 16S rRNA gene sequencing, the maximum PHAs yielding strain was identified as Bacillus cereus MUL-A. Effect of different physicochemical parameters such as temperature, pH, incubation time and composition of the modified PHA production media (PPMG) were studied on the polyhydroxyalkanoates (PHAs) yield. After 72 hours of submerged fermentation, a significantly high yield of PHAs i.e. 64.3% w/w were produced by the Bacillus cereus MUL-A strain by using PPMG medium having glucose (10 g/L) as carbon source and peptone (2 g/L) as nitrogen source at 35 degrees C, pH 7.0. Provision of agricultural residues i.e. crude molasses and acid treated molasses as carbon source (6% v/v) & peptone (2 g/L) as nitrogen source in the PPMG medium has resulted in 36.9% and 44.6% biosynthesis of PHA content, respectively. Characterization of the purified PHA by Fourier transform infrared (FTIR) spectroscopy determined its purity and major functional groups.