独立栄養細菌の有機物質化能と生育阻害

概要

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The effect of organic compounds on the growth of chemoautotrophic bacteria was studied from the viewppoints of inhibition and assimilation. At low concentrations glucose was assimilated effectively by Thiobacillus thiooxidans and Thiobacillus ferrooxidans, and then activities of several enzymes of the TCA cycle were found in the extracts of the bacterial cells, as well as hexokinase. But, the growth of T. ferrooxidans was strictly dependent on CO_2 as the carbon cource and Fr^<2+> as the energy source. It is thought that the activities are too low to acquire satisfactory energy for the life process, though the bacteria possess the ability to metabolise organic compounds, so the enzymes mainly control the biosynthesis.From the viewpoint of inhibition, iron oxidase in T. ferrooxidans was inhibited by pyruvic acid, and in T. thiooxidans activities of enzymes which mediate the oxidation of elemental sulfur were inhibited by various organic acids. Especially AMP-independent sulfite oxidase (EC 1.8.3.1) was completely inhibited by adding 10^<-5>M pyruvic acid, oxalacetic acid, succinic acid, fumaric acid, or maleic acid. From these results, it is postulated that the direct inhibition of enzymes in the energy-acquiring mechanism might be one of the reasons why organic acids inhibit the growth of chemoautotrophic bacteria.
社団法人日本生物工学会の論文
1980-05-25