[Prolonged cultivation of an anaerobic bacterial community producing hydrogen].

This paper studies various methods of long-term maintenance of the process of hydrogen evolution during the growth of an aerobic bacterial community on a starch-containing environment. When cultured in separable trip fermentation mode for 72 days, from 0.10 to 0.23 H2/l of medium/day was formed. The regime of regular reseeding lasted more than 100 days, forming an average of 0.81 1 H2/l of medium/day. The advantages and disadvantages of different methods of microbial hydrogen production during a dark starch fermentation process are presented. From the obtained H2 forming microbial communities, we isolated an anaerobic spore-forming bacterium (strain BF). Phylogenetic analysis of the 16S RNA gene sequence of the new strain showed that according to its genotype it belongs to the Clostridium butyricum species.

[Minimal synthetic nutrient medium for Clostridium stricklandii bacteria]. / Minimal'naia sinteticheskaia pitatel'naia sreda dlia bakterii Clostridium stricklandii.

A composition of minimal culture medium for the anaerobic bacterium Clostridium sticklandii strain CSG was determined. A fully synthetic culture medium promoting the cell yield up to 1 g dry biomass per 1 1 was found. It is composed of 13 amino acids, sodium formiate, four vitamins, microelements and salts. The strain under study does not utilize glucose as a carbon and energy source.

[Glucose metabolism in Clostridium sporogenes and Clostridium sticklandii bacteria]. / Metabolizm gliukozy u bakterii Clostridium sporogenes i Clostridium sticklandii.

Clostridium sporogenes 272 has a high rate of glucose fermentation. Its cell-free extract contains all glycolytic enzymes catalysing glucose degradation to pyruvate and shows the phosphoroclastic activity. C. sticklandii CSG has a low rate of glucose fermentation. Hence, the activity of the following enzymes is lower in this organism comparing to C. sporogenes: phosphohexoisomerase (EC 5.3.1.9), phosphofructokinase (EC 2.7.1.11), aldolase (EC 4.1.2.13), triosephosphate isomerase (EC 5.3.1.1) and glyceraldehyde phosphate dehydrogenase (EC 1.2.1.12). Moreover, it is possible that the system of glucose transport into the cell is damaged in C. sticklandii.

[Catabolism of threonine in the bacterium Clostridium sticklandii]. / Katabolizm treonina u bakterii Clostridium sticklandii.

Catabolism of L-threonine in the anaerobic bacteria Cl. sticklandii has been studied. Degradation of this amino acid was shown to occur with participation of the following enzymes: NAD-dependent L-threonine-3-dehydrogenase (EC 1.1.1.103), glycine acetyltransferase (EC 2.3.1.29), phosphotransacetylase (EC 2.3.1.8) and acetate kinase (EC 2.7.2.1). The presence of the first two enzymes in Clostridia has been shown for the first time. A scheme of threonine oxidation down to acetic acid and glycine by Cl. sticklandii was proposed. The oxidation of one threonine molecule is coupled with phosphorylation of one ADP molecule and reduction of one NAD+ molecule.

[Synthetic medium for culturing Clostridium sporogenes]. / Sinteticheskaia sreda dlia kul'tivirovaniia Clostridium sporogenes.

Clostridium sporogenes was shown to be capable of good stable-growth and biomass accumulation up to 5 mg/ml (dry weight) in a chemically defined medium. Along with glucose, the culture required the following amino acids for its growth: arginine, phenylalanine, glycine tyrosine, leucine, isoleucine, valine, tryptophan, and methionine. The culture could grow in the absence of inorganic nitrogen but required such elements as phosphorus, iron and magnesium. Addition of cysteine to the medium accelerated the growth and increased the biomass yield. Leucine at a concentration over 0.1% inhibited the growth. Two vitamins, viz. biotin and p-aminobenzoic acid, are sufficient for the growth of the culture.