Dynamics and optimal conditions of intracellular ectoine accumulation in Brevibacterium sp

The optimal conditions for the intracellular synthesis of ectoine were determined in a halotolerant Brevibacterium sp. The size of the intracellular ectoine pool in the bacterial cells is shown to depend on the external salt concentrations, type of carbon source and aeration level. In erlenmeyer flasks a maximum concentration of intracellular ectoine of about 0.9 g/l was obtained. Under controlled aeration in a 1.5 l fermentor this level could be increased to 1.2 g/l. Consecutive cell transfers to media with increasingly higher salt concentrations enabled us to reach even higher levels, up to 1.6 g/l on erlenmeyer scale. The ectoine synthesis takes place immediately after the osmotic upshock. Within one generation time, the new corresponding specific intracellular ectoine concentration is reached.