Bacteria that grow on methane as the sole source of carbon and energy are considered promising targets for biotechnological development. We have obtained modified strains of the obligate methanotroph Methylotuvimicrobium alcaliphilum with deleted genes of glucokinase (glk), sucrose-phosphate synthase (sps), α-glucanotransferase (malQ), and trehalose synthase (treS). All these strains were characterized with elevated trehalose content in the biomass, with the maximum level of 1.2 mg trehalose per 1 g of dry cell weight accumulated by the culture of the strain ∆glk∆sps∆malQ∆treS. Introduction of a heterologous treT gene encoding trehalose synthase (EC 2.4.1.245) from Methylomicrobium album BG8 did not increase trehalose content in M. alcaliphilum cells. It was shown that glycogen degradation occurs with production of the trehalose intermediate, while trehalose synthase (EC 5.4.99.16) and α-glucanotransferase serve for its utilization.
Khmelenina et al. (Mon,) studied this question.