A series of two-component polyhydroxyalkanoates consisting of hydroxybutyrate and hydroxyvalerate monomer at different ratios were synthesized using the bacterium Ralstonia eutropha B5786. The properties of polyhydroxyalkanoates were compared with those of the homopolymer of hydroxybutyric acid by X-ray structure analysis, IR spectroscopy, differential scanning calorimetry, and viscosimetry. With an increase in the molar fraction of hydroxyvalerate, an equalization of the ratio of the crystalline and amorphous phases in the copolymer was observed. The degree of crystallinity of the polymer decreased from 70-80 to 45-50%; in the range of an increase in the hydroxyvalerate molar fraction from several to 25-30 mol %, the dependence was linear. The temperature characteristics, the melting temperature (T-m), and the degradation temperature (T-d) were lower in polyhydroxyalkanoates than in polyhydroxybutyrate, for which T-m and T-d were 168-170 and 260-265degreesC, respectively. In the copolymer, as the molar fraction of hydroxyvalerate grew, both parameters decreased. In the range of variation of monomer ratio studied, they decreased to 150-160 and 200-220degreesC, respectively. No distinct correlation between the composition of the polymer and its molecular mass was found.

A series of two-component polyhydroxyalkanoates consisting of hydroxybutyrate and hydroxyvalerate monomer at different ratios were synthesized using the bacterium Ralstonia eutropha B5786. The properties of polyhydroxyalkanoates were compared with those of the homopolymer of hydroxybutyric acid by X-ray structure analysis, IR spectroscopy, differential scanning calorimetry, and viscosimetry. With an increase in the molar fraction of hydroxyvalerate, an equalization of the ratio of the crystalline and amorphous phases in the copolymer was observed. The degree of crystallinity of the polymer decreased from 70-80 to 45-50%; in the range of an increase in the hydroxyvalerate molar fraction from several to 25-30 mol%, the dependence was linear. The temperature characteristics, the melting temperature (T(m)), and the degradation temperature (T(d)) were lower in polyhydroxyalkanoates than in polyhydroxybutyrate, for which T(m) and T(d) were 168-170 and 260-265 degrees C, respectively. In the copolymer, as the molar fraction of hydroxyvalerate grew, both parameters decreased. In the range of variation of monomer ratio studied, they decreased to 150-160 and 200-220 degrees C, respectively. No distinct correlation between the composition of the polymer and its molecular mass was found.

Some morphological, physiological, and biochemical manifestations of heterogeneity in the population of the hydrogen-oxidizing bacterium Alcaligenes eutrophus Z1 were studied. The population dissociated into R and S variants differing in the size, appearance, and architectonics of colonies, cell ultrastructure, growth rate, enzyme activity, and chemical composition. Heterogeneity also manifested itself in different responses of cells to antibiotics, surfactants, and elevated temperature.

Two chemolithoautotrophs-the hydrogen-oxidizing bacterium Alcaligenes eutrophus and the carboxydobacterium Seliberia carboxydohydrogena-were investigated with respect to their ability to produce heteropolymeric polyhydroxyalkanoates (PHA) during mixotrophic growth on CO;! and medium-chain-length (Cg to Cg) alkanoic acids. Hydroxy derivatives of the alkanoic acids were incorporated into PHA synthesized by the bacteria studied in proportions dependent on the time of cultivation. Irrespective of the nature of the acid added to the medium, PHAs were found to contain hydroxybutyrate as the main constituent and also hydroxyvalerate and hydroxyhexanoate, whose maximal incorporation was observed 4 to 6 h after the addition of an alkanoic acid to the medium. During further cultivation, the fractions of hydroxyvalerate and hydroxyhexanoate in PHA decreased, and the fraction of hydroxybutyrate and the total intracellular content of the polymer increased. Three-component polyhydroxyalkanoates with different proportions of hydroxybutyrate, hydroxyvalerate, and hydroxyhexanoate were obtained, and some of their properties were analyzed.

The growth, productivity, and changes in the chemical composition of the green alga Botryococcus braunii Kutz H-252 were studied at different phases of growth in a luminostat culture. Modification of the Prat medium resulted in an increase in the alga yield to 3.9 g/l and a decrease in the generation time to 3-4 days. The specific growth rate during the exponential phase was 0.235/day. These values are comparable with the best results obtained abroad. Among the pigments of B. braunii, besides chlorophylls a and b, carotene, lutein, neoxanthin, and violaxanthin were also identified. The highest content of these pigments, based on dry weight, was achieved during the exponential growth phase. During culture aging, there was an accumulation of carbohydrates and lipids in addition to a simultaneous decrease in the concentration of nitrogen-containing substances. It was discovered that this strain can synthesize liquid hydrocarbons. These hydrocarbons were found both in the alga biomass (ca. 1% of dry weight) and among the extracellular metabolites (up to 10.3 mg/l).

Biodegradation of polyhydroxyalkanoates (PHA)-polymers of hydroxylated fatty acids-differing in chemical composition, crystallinity, melting temperature, and molecular weight was studied in soil and water environments under conditions of varying ambient temperature and pH. Under similar conditions, homogeneous films of polyhydroxybutyrate (PHB) with different initial properties were degraded at virtually equal rates. Hydroxybutyrate-hydroxyvalerate copolymers with a lower crystallinity and different microstructure in comparison to PHB were degraded at a 20 to 30% higher rate on average. The ambient temperature significantly influenced the rate of PHA biodegradation.

The CO oxidase (COX) activity of carboxydobacteria Seliberia carboxydohydrogena cells a cells and the rate of CO oxidation by this culture were studied under various modes of fermentation, The CO oxidase activity of cells was maximal (60-80 U) during limitation of bacterial growth by the source of energy or carbon. The rate of CO oxidation by the culture was 1.4-1.7 l/g. The adaptive type of dependence of the CO oxidase activity of cells on the concentration of CO in the medium within the range of 0-20% was established.

The effect of different cultivation parameters on the specific activities of soluble and membrane-bound hydrogenases was studied in Alcaligenes eutrophus Z-1 cells. These activities were shown to be dependent primarily on the availability of electrons from the substrate used. Changes in cultivation temperature and oxygen concentration versus the optimal values as well as addition of low amounts of carbon monoxide to the gas phase exerted a lesser effect on the specific hydrogenase activities. Autotrophic and heterotrophic methods were developed for growing A. eutrophus Z-1 cells with a high hydrogenase activity.