Isolates of Comamonas spp. exhibiting catalase and peroxidase activities and diversity of their responses to oxidative stress

For survival isolates of Comamonas testosteroni CCM 1931, C. testosteroni K3, C. terrigena N3H or N1C and C. terrigena CCM 2409, selected largely from polluted environments, the production of catalase and dianisidine-peroxidase activity was important. Electrophoretic resolution of cell-free extracts of aerobically grown strains in Luria-Bertani medium during the exponential phase revealed distinctive expression of catalatic and peroxidatic activities detected with 3,3′-diaminobenzidine tetrahydrochloride (DAB). The protection of isolates from 20 or 40 mM H2O2 stress was characterized with a considerable diversity in catalase and peroxidase responses that resulted from hydroperoxidase’s variant of original isolates, indicating also a selective pressure of environment. Results indicate catalase to be important for adaptation of cultures to high concentration of 60 mM H2O2. The greatest appreciable differences in sensitivity to toxic effect of H2O2 (20 or 40 mM) treatment between individual isolates and their adapted variants during the growth were observed until the middle of exponential phase. Isolates exhibited diversity in catalases responses to possible contaminants o-or p-phenylenediamine (PDA) as well. Only positional isomer p-PDA (1 or 2 mM) stimulated catalase activity unlike from isomer o-PDA in C. terrigena N3H cells. The study can contribute to understanding of bacterial antioxidative enzymatic responses in the presence of possible physiological stress resulting mainly from environmental pollutants.