Degradation of maltose by proliferating cells of Desulfovibrio desulfuricans 2198.

Desulfovibrio desulfuricans 2198 can grow on maltose-based medium only in the presence of yeast extract. The results of kinetic measurements of maltose consumption by the cells show that there is no marked difference in Km and Vmax values for this bacterium versus other carbohydrate-utilizing microorganisms. The determination of some enzymes of sugar metabolism in D. desulfuricans 2198 suggests that maltose degradation occurs by the Embden--Meyerhof pathway. The cell extract also contains glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. 2-Keto-3-deoxy-6-phosphogluconate aldolase, the key enzyme of the Entner--Doudoroff pathway, is not found in D. desulfuricans 2198. In the bacterium grown on [U-14C]maltose-containing medium, a portion of the labeled carbon is incorporated into biomass. As degradation products, labeled acetate and carbon dioxide are found.

[Characteristics of nitroreduction as the key stage in the microbial destruction of aromatic nitro compounds]. / Osobennosti nitroreduktsii kak kliuchevogo étapa mikrobnoi destrultsii aromaticheskikh nitrosoedinenii.

The reduction of nitrogroups of 2,4,6-trinitrotoluene (TNT) and other nitroaromatic compounds under the influence of Pseudomonas denitrificans and Escherichia coli enzymes was investigated. Quantitative measurements of the immediate stable products of TNT reduction showed that its reducing attack increased with bacterial age. However, preferential reduction of the nitrogroup in position 2 was typical of bacterial cells of any age, being maintained at pH 5.5 to 7.8. The bacterial reduction in vitro was NAD(P)H- (or NAD(P)H-generating systems) dependent. The nitroreduction was stimulated by only FAD and Mn2+ and Mg2+ out of flavins and metal ions tested. The lack of substrate specificity in the nitroreductases under study is indicated by the reducing capacity (in descending order) of nitroderivatives of benzene, toluene, benzoate, and phenol.