Abstract

Polyhydroxybutyrates (PHBs) are synthesized and deposited as cytoplasmic inclusions in various bacteria like Rhizobium sp., Rhodobacter sphaeroides, etc. This work was focused on isolating a PHB-producing bacterium capable of growing in conventional media used for industrial biopolymer production, its physiological and molecular identification and characterization. Thus, a bacterial isolation process was carried out from samples of root nodules of various leguminous plants. Synthetic plastics pose a number of serious problems. Therefore, there is an urgent need to have a biodegradable alternative to these synthetic polymers. Rhizobium spp. is able to produce PHB which can be used as biodegradable plastic. Although, the cost of production is high because of high cost of media ingredients and chemicals used for their extraction from the cell. In the present study, attempts have been made to isolate and characterize the Rhizobiumisolates capable of producing PHB and to analyze the effect of cheap carbon and nitrogen sources on their growth and PHB production.

Key words: Polyhydroxybutyrate, biodegradable plastic, Rhizobium.