RESUMEN

The methanogenic activity of manure destructors was investigated at different stages of cattle manure utilization at 35 degrees in a three-section horizontal methane tank manufactured by "Enbom" company (Finland). The association of microorganisms was found to have the highest activity at the last stage of the process, while the least activity was observed in case of fresh manure. A considerable increase of the methanogenic activity in the methane tank was proved by the radioisotopic method and by calculation of the population size of microorganisms from different groups by the series dilution method. Acetic and propionic acids were absent in samples from the third section of the methane tank, while the maximum concentration of the acids was found in the manure storage and in the first section of the methane tank. A significant part of active methanogenic microorganisms was removed with the effluent. Therefore, partial recirculation of the biomass should be used to increase the efficiency of the methane tank.

Asunto(s)

RESUMEN

The content of microbial biomass and the concentration of volatile fatty acids were comparatively studied in the tanks where the waste products of three stock farms were subjected to methane fermentation. The biomass content was shown to vary from 19 to 30% of the dry matter weight and the concentration of volatile fatty acids from 0 to 4.5 g per litre. The low concentrations of acetic and propionic acids together with the high biomass content were indicative of an active balanced microbial association. The parameters can be used to assess the operation of methane fermentation tanks.

Asunto(s)

RESUMEN

A methylotrophic denitrifying bioenosis composed of hyphomicrobes and paracocci was isolated from the active ooze in a system of sewage purification from nitrates. The morphological and physiological characteristics of the isolated Hyphomicrobium sp. Z-115 and Paracoccus denitrificans Z-100 and Z-121 strains differed from those of the type strains, which made it difficult to identify them and to isolate them as a pure culture. This should be taken into account while determining the agents operating in such purification systems. The rate of growth, the rate of nitrate reduction and the activity of enzymes involved in methanol assimilation are higher in the anabolic syntrophic bicenosis than in its components in pure culture. A combined culture composed of the collection Hyphomicrobium and Paracoccus strains was neither effective nor stable under the conditions of anaerobic growth with nitrate and methanol. Therefore, the natural biocenosis af the purification system cannot be substituted by an artificial one composed of the collection cultures.

Asunto(s)

RESUMEN

Possible involvement of the catalase mechanism in the elimination of nitrous oxide was studied in model experiments. The concentration of N2O in the gaseous phase was found to decrease due to the decomposition of hydrogen peroxide by catalase. The concentration of NO increased accompanying the removal of N2O from the gaseous phase in the pressure of H2O2 and catalase. Though the observed effect is slight, the oxidation of nitrous oxide during the decomposition of H2O2 by catalase might be one of the mechanisms for biological elimination of N2O under the oxidating conditions.

Asunto(s)

RESUMEN

The ability of bacteria to eliminate nitrous oxide (N2O) from a gaseous phase containing 20% O2 was studied. Representatives of the following physiological groups were found to be incapable of removing N2O: denitrifying bacteria (Paracoccus denitrificans), nitrifying bacteria (Nitrosospira briensis), carboxydobacteria (Pseudomonas carboxydoflava), methane oxidizing bacteria (Methylosinus trichosporium), and nitrogen fixing bacteria (Bacillus polymyxa). Five corynebacteria-like strains were isolated from soil samples actively eliminating N2O under oxidative conditions. None of the strains could remove considerable amounts of N2O in pure culture. The rate of N2O elimination was much higher than that of the initial cultures if a combined culture comprising five strains was used. Three strains of the combined culture formed H2O2 and possessed a low catalase activity whereas the remaining two did not produce H2O2 and decomposed hydrogen peroxide at a high rate; this suggests that the catalase mechanism is involved in the elimination of N2O.

Asunto(s)

RESUMEN

The effect of nitrate, nitrogen oxide, sulphate, oxidized iron and manganese on the methane fermentation of cellulose was studied with the enrichment bacterial culture. The action of these oxidants on the enrichment culture growing on cellulose was compared to that on a pure methanosarcina culture in order to find out which stage of methane formation from cellulose was inhibited. Nitrate at the concentration of 2 g NaNO3 and more per litre of the medium inhibited the whole process of fermentation; at the concentration less than 2 g/l the production of methane was inhibited, and cellulose decomposition was accompanied with denitrification. Sulphate at the concentration of 2 g MgSO4 per litre had no effect on the formation of methane but the process was inhibited by the product of its reduction, i. e. sulphiade. Cellulose decomposition could be accompanied with sulphate reduction if sulphide produced in the process of the reduction were removed from the medium. In this case as well as in the presence of ferric iron, the production of methane was inhibited due to competition for the reducing agent.

Asunto(s)

RESUMEN

The dynamics of label distribution was studied in the products of 14CH3OH assimilation by the cells of Pseudomonas gazotropha Z-1156. Substances to be first detected were glycolate, glycine and those of the chromatogram "start" spot. Later, the radioactivity was detected in phosphorylated compounds and glycerate. Cell extracts of Ps. gazotropha Z-1156 contained ribosephosphate isomerase, phosphoribulokinase and glyceraldehyde dehydrogenase but not ribulosediphosphate carboxylase. Distribution of the label in the products of 14CH3OH assimilation and the presence of active hydroxypyruvate reductase in the extract suggest that the serine cycle is involved in methylotrophy of Ps. gazotropha Z-1156. This suggestion is confirmed by the presence of active formate dehydrogenase, phosphoenolpyruvate carboxylase, (NADP+, Mn2+)-specific isocitrate dehydrogenase, (NAD, Mg2+)-specific malate dehydrogenase, malate lyase, and isocitrate lyase. The citric acid cycle is open at the alpha-ketoglutarate dehydrogenase system. The dry biomass of Ps. gazotropha Z-1156 contains over 70% of protein.

Asunto(s)

RESUMEN

The incorporation of 14CO into acid-stable assimilation products by Pseudomonas gazotrophia Z-1156 is characterized by a slow rate at the beginning, contrary to the rectilinear kinetics for incorporation of the bicarbonate 14C in the presence of 12CO. The assimilation of 14C-bicarbonate decelerates in the absence of CO. The relative content of 14C is the highest in phosphorylated compounds upon the shortest possible incubation of the cells of P. gazotropha Z-1156 (5 min) in the presence of 14CO and O2, and decreases in the process of incubation. The bulk of radioactivity is found in aspartate and glutamate. The composition of products formed upon the assimilation of 14CO and NaH14CO3 (in the presence of 12CO) during 15 min is similar. The key enzymes of the reductive pentose phosphate cycle have been found in the cell extracts of P. gazotropha A-1156. The specific activity of carboxylating enzymes of the Calvin cycle in the cell extracts increases in the course of proportional growth and sharply decreases when the growth of the culture decelerates. The activity of ribulose diphosphate carboxylase (EC. 4.1.1.39) is always by one-two orders lower than that of ribulose phosphate isomerase (EC. 5.3.1.6) and phosphoribulokinase (EC.2.7.1.19), but is similar to the activity of phosphoenolpyruvate carboxylase (EC. 4.1.1.31). The activity of phosphoenolpyruvate carboxykinase (EC. 4.1.1.32) has not been detected in the cells extracts of P. gazotropha Z-1156.

Asunto(s)

RESUMEN

The process of biological N2O elimination under oxidative conditions has been discribed. It was performed by samples of soil, litter, water, ooze, sewage and compost. The process differs from denitrification, is not accompanied with dinitrogen formation and its rate is maximal at 15% of oxygen in the gaseous phase. Acetylene, an inhibitor of denitrification has no effect on elimination of nitrous oxide under oxidative conditions.

Asunto(s)

RESUMEN

Early products of 14CO2 assimilation by a new microorganism Stibiobacter senarmontii are phosphoglyceric acid, phosphorous esters of sugars and aspartic acid, as was shown by chromatography and radioautography. Extracts of the cells displayed the activity of ribulosediphosphate carboxylase and phosphoenolpyruvate carboxylase (1 mU and 0.24 mU per 1 mg of protein in the extract, respectively). Therefore, the microorganism is capable of autotrophic nutrition involving mechanisms of the reductive pentosephosphate cycle. The latter seems to operate even in conditions of deficiency of the energy substrate which is caused by low solubility of antimony trioxide.

Asunto(s)

RESUMEN

Oxygenase transforamtion of ribulose-1,5-diphosphate was found in the hydrogen bacterium Hydrogenomonas eutropha Z-1. Oxygen inhibits the carboxylating activity of ribulose-1,5-diphosphate carboxylase by 42% at a low concentration of the substrate of carboxylation--bicarbonate. The oxygenase activity of this carboxylase is saturated at 50% of oxygen in the atmosphere.

Asunto(s)

RESUMEN

An enzymatic method is suggested for determining the role of chemoautotrophs in bacterial populations of a high density. The method involves an assay of the activity of ribulose-1,5-diphosphate carboxylase, the key enzyme in autotrophic assimilation of carbon dioxide. The chemoautotrophic activity of microorganisms is rather high in ecosystems based on decomposition of organic matter in both aerobic and anaerobic conditions.

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)

Asunto(s)