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Iu R Malashenko

Publications and source records attributed to Iu R Malashenko.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

[Transformation of substrates not used for growth by the immobilized methane-oxidizing bacteria].

The article deals with the theoretical problems of obtaining certain substrates transformation products using immobilized cells of the methane-oxidizing bacteria. This process is based on the ability of these bacteria to cometabolize the substrates which are not used for growth. The methane-oxidizing bacteria are shown to utilize ethane during growth on methanol. Cometabolism of ethane and methanol occurs due to the presence of conjugated points of these substances oxidizing reactions as well as of the oxidation products assimilation reactions. The optimal concentrations of ethane and methanol are established for the methane-oxidizing bacteria growth and for formation of the ethane oxidation products by means of the immobilized cells.

Ethane↗
PubMedDate not supplied

[Immobilization of methane-oxidizing bacterial cells].

The purpose of this work was to study how the conditions for immobilizing the cells of the methane oxidizing bacterium Methylomonas rubra using chemical and physical techniques influence their functional catalytical properties. These properties were found to depend on the chemical nature of a matrix and the mode of binding the cells to the carrier. The best carriers were shown to be silochrome with introduced carboxy groups and agar gel.

Agar↗
PubMedDate not supplied

[Theoretical evaluation of necessity of carbon dioxide assimilation by microorganisms during growth on various substrates].

The biological role of exogenous carbon dioxide during substrate assimilation with a various degree of reductivity is evaluated. The investigation of metabolic pathways of carbon dioxide incorporation into the metabolic processes of methaneoxidizing bacteria shows that the HCO3- ion assimilation is catalyzed by phosphoenolpyruvate carboxylase and in certain strains also by the key enzyme of autotrophic pathway of the carbon dioxide assimilation, ribulose-1,5-diphosphate carboxylase. The theoretical calculations and experimental studies indicate that exogenous carbon dioxide is a necessary participant of the metabolic processes of methane or methanol assimilation. It is also an acceptor of the excess electrons of these compounds. It is the degree of reductivity of the substrate metabolized that determines the activity of the exogenous carbon dioxide fixation by microorganisms. The carbon dioxide fixation by heterotrophic microorganisms must be considered, therefore, as a process which is mostly due to the elementary composition of the source of carbon under conversion.

Bacteria↗
PubMedDate not supplied

[Comparative characteristics of the enzymatic systems of methane-utilizing bacteria that oxidize NH2OH and CH3OH].

Methane hydroxylase (MH) from the obligate methane assimilating culture of Methylococcus thermophilus catalyses oxygenation of both CH4+ and NH4+; therefore, we studied the specificity of enzyme systems catalysing the subsequent oxidation of compounds produced upon the oxygenation of these substrates (CH3OH and NH2OH). CH3OH and NH2OH were shown to be oxidized by different enzymes, viz. methanol dehydrogenase (MD) and hydroxylamine oxidase (HO), respectively. Similar to MH, MD is characterized by the absence of strict substrate specificity, and catalyses oxidation of primary alcohols other than methanol, rather than hydroxylamine. HO catalyses oxidation of hydroxylamine rather than methanol and possesses the activity of hydroxylamine:cytochrome c oxidoreductase. The constitutive character of HO from the methane assimilating bacteria and the substrate specificity of the enzyme suggest that a lithotrophic pathway for producing energy operates in these bacteria. The HO of Methylococcus thermophilus is similar in certain properties to the HO of the nitrifying bacterium Nitrosomonas europaea.

Alcohol Oxidoreductases↗