Characterisation of Polyhydroxy Butyrate (PHB) from Bacillus Subtilis Strain P Isolated From Rhizosphere Soil

Abstract

Polyhydroxy Butyrate (PHB) is a biodegradable polymer material with nontoxic characteristics. In this paper we report PHB production from bacterial isolate from rhizosphere soil. PHB production by the isolates was confirmed by Sudan black and Nile blue staining methods. The physical, colonial, morphological and biochemical characteristics of the isolate were noted. For further confirmation of identity, 16s rDNA sequencing and BLAST search was performed. The results showed that the isolate had highest homology (100%) with Bacillus subtilis strain P. The phylogenetic tree was constructed to identify the evolutionary relatives of the isolated bacteria. The optimum conditions for PHB production were studied. An optimum PH of 7and incubation period of 24 hours were found to be appropriate for maximum production of PHB. Yeast extract and Mannitol were found to be most ideal nitrogen and carbon source respectively for the production of PHB. The extraction of PHB was done using crotonic acid method and further the characterization was done by FTIR and NMR analysis. The peaks in the FTIR data corresponds to the probable presence of C=O valence, CH2-S groups or ester C-O groups whereas the molecular composition of the polymer as indicated NMR analysis, indicates the presence of CH bridges.