Control of autolysis of Bacillus subtilis for selective production of the intracellular enzyme glucose-6-phosphate dehydrogenase in aqueous two-phase systems

Abstract

A method for the release of intracellular enzyme by autolysis of Bacillus subtilis cells is presented. Both the growth and lysis processes were further applied to aqueous two-phase systems (ATPS). Lysis induced by the addition of Triton X-100 and by low-temperature treatment facilitated the release of cytoplasmic enzyme glucose-6-phosphate dehydrogenase (G6PDH) in ATPS. The release selectivity increased when lysis was regulated by the addition of 50 μM or 100 μM Triton X-100. Cardiolipin efficiently inhibited the autolytic process. Control of the autolytic system promoted the selective release of G6PDH. B. subtilis cells could be grown and lysed in aqueous two-phase systems in a similar fashion to the conventional single-phase medium solutions. The released enzymes were partitioned according to their surface properties. G6PDH were extracted to the top phase in a PEG1540/Dex100K-200K sytem. Cells were partitioned to the bottom phase or the interface, and could be recycled into the fermentor. The selectivity of enzyme production was also increased in two-phase systems by the addition of cardiolipin.