Mutagenesis of Bacillus thuringiensis IAM 12077 for increasing poly (-b-)hydroxybutyrate (PHB) production

Authors : Pal ADWITIYA, Prabhu ASHWINI, Arun Kumar AVINASH, Rajagopal BADRI, Dadhe KAJAL, Ponnamma VOMSI, Shivakumar SRIVIDYA

Pages : 225-230

View : 13 | Download : 5

Publication Date : 2009-12-01

Article Type : Research Paper

Abstract :A gram-positive bacterium that accumulated PHB was isolated from local garden soil in Bangalore. Based on its morphological and physiological properties, and nucleotide sequence insert ignore into journalissuearticles values(about 1.5 kb); of its 16S rDNA it was identified as Bacillus thuringiensis IAM 12077. In this study the PHB-producing capacity of putative mutant strains of Bacillus thuringiensis IAM 12077 was evaluated. A Bacillus sp. identified as a Bacillus thuringiensis IAM 12077 strain capable of producing 10%-15% dry cell weight insert ignore into journalissuearticles values(DCW); PHB when grown in nutrient broth for 48 h was subjected to random mutagenesis [physical insert ignore into journalissuearticles values(UV); and chemical insert ignore into journalissuearticles values(acridine orange);]. Among the UV-mutants screened, 19 putative mutants produced more PHB than the parental, while 2 strains produced less. Of these mutants, B8 exhibited promising PHB accumulation insert ignore into journalissuearticles values(24.68%; 1.54-fold); with more PHB production insert ignore into journalissuearticles values(1.3 g/l; 5.4-fold); than the parental strain. Chemical mutagenesis yielded putative mutants, of which 6 had a decrease, 3 had no change, and 2 had an increase insert ignore into journalissuearticles values(B3, C2); in PHB production. While the increase in accumulation insert ignore into journalissuearticles values(19.69%, 1.43-fold and 22.22%, 1.62-fold, respectively, for B3 and C2); was comparable to the increase shown by the UV mutant insert ignore into journalissuearticles values(B8);, the yields did not concomitantly increase insert ignore into journalissuearticles values(0.43g/l, 1.13-fold and 0.6g/l, 1.57-fold, respectively);.
Keywords : Key words Bacillus thuringiensis IAM 12077, Poly b, hydroxybutyrate, random mutagenesis