[Formation of free ketoacids by barotolerant bacteria under conditions of increased pressure].

The effect of elevated hydrostatic pressure on biosynthesis of keto acids by barotolerant bacteria growing on glucose-mineral media is discussed in this paper. Strains which are more tolerant to the action of pressure can liberate exocellular keto acids. Keto acids are synthesized at a low content of glucose and a relatively high concentration of nitrogen in the presence of dissolved oxygen. Pressure may either induce or inhibit the synthesis. A shift towards oxalacetate in the composition of keto acids caused by the action of pressure shows that anabolism and catabolism are decoupled. Free exocellular keto acids are not found in bacteria, which do not grow at 500 atm. either at atmospheric or elevated pressures; therefore, their metabolism is more balanced. Differences in the growth of barotolerant bacteria, and in biosynthesis of keto acids at elevated pressure, may be caused by different response of various strains and species of barotolerant bacteria to the action of this factor.