Highly potential compatible solute from halotolerant Bacillus subtilis MA04: Its functional and molecular characterization

Glycine betaine (N, N, N-trimethylglycine) is an effective compatible solute, which maintains fluidity of membranes and protects the biological structure of the organisms under stress. In this study, glycine bataine biosynthesis genes; betaine aldehyde dehydrogenase (GbsA) and betaine alcohol dehydrogenase (GbsB) from halophilic Bacillus subtilis MA04 was heterologously expressed in Escherichia coli M15 (pREP4). The recombinant enzyme was purified by column chromatography using DEAE sepharose. The purified enzyme revealed a five-fold increase in the activity with choline as substrate and phenazine methosulfate as electron acceptor, compared to the control strain. The glycine betaine biosynthesis gene sequences reported in this study were diverse and appeared to be partially conserved with the GenBank reported sequences of many eubacteria, with subsequent amino acid changes in the translated proteins.