The role of low-molecular-weight nitrogen compounds in the osmotolerance of Rhodococcus erythropolis and Arthrobacter globiformis

Investigations showed that Rhodococcus erythropolis E-15 and Arthrobacter globiformis 2F cells respond to osmotic shock by increasing the synthesis of free amino acids, primarily glutamic acid (80% of the intracellular free amino acid pool). The osmoprotective role of glutamic acid follows from its beneficial effect on the growth of bacteria in high-salinity media. It was found that the addition of this amino acid to the growth medium at a concentration of 2 mM shortened the lag phase and increased the growth rate and biomass yield of either of the two bacteria. The addition of another osmoprotectant, trehalose, to the high-salinity growth medium of R. erythropolis E-15 at the same concentration (2 mM), restored the growth parameters of this bacterium to the control values.