Acta microbiologica Polonica. Series B: Microbiologia applicata最新文献

Glutamate-glyoxylate aminotransferase which mediates the reaction of glyoxylic acid with glutamic acid to yield glycine and alpha-oxoglutaric acid has been isolated and purified 84-fold from extracts of Lactobacillus plantarum. Purified enzyme requires the addition of pyridoxal phosphate and magnesium ions for its activity. The molecular weight of the enzyme estimated by Sepharose 4B gel filtration amounts to 37.000. Micaelis constants for glyoxylate and glutamate are corresponding to 6.25 X 10(-3) M and 2.75 X 10(-3) M, respectively. Optimal pH in phosphate and veronal buffers is 8.0 and optimal temperature 35--37 degrees C.

Qualitative and quantitative studies were carried out on the production of auxins by Coryneform bacteria, the only bacterial types isolated from roots of pine seedlings. Almost all isolates were capable of producing auxins in tryptophan containing media. In media without this amino acid only trace or no auxins were produced. Most of the bacteria studied synthesized auxins located on the chromatograms run with isopropanol, ammonia, water (10:1:1 v/v) at Rf 0.3--0.5. Moreover substances with Rf values 0.05--0.2 and 0.8--1.0 were produced by some strains. No plant growth inhibitors detected with the Avena coleoptiles biotest were produced by the bacteria studied.

Glucose added to soil and to the culture medium of Penicillium citrinum stimulated simazine decomposition. Differences in the rate of simazine decomposition depended on the dose of glucose. Both in soil and in the medium the rate of simazine decomposition was connected with the intensity of development of microorganisms.

The fungi Pleurotus ostreatus and Trametes pubescens were grown in a mineral medium containing 1% of glucose and 0.9% of lignosulfonates introduced into the culture medium in the form of yeast waste liquor. Chromatography of extracts of the medium and determinations of sulphur and lignosulfonates have revealed that the fungi studied utilized the constituents of the yeast waste liquor (lignosulfonates) as carbon source. This was manifested in an increase of dry mass of the mycelium and protein as compared with the control. The constituents of the yeast waste liquor were also found to have a stimulating effect on the formation of both exo-and endoenzymes, laccase and peroxidase. This may indicate that these oxidases take part in the decomposition of lignosulfonates.

Comparative studies on the influence of 4 amino acids (cysteine, cystine, methionine and alanine) on the activity of enzymatic preparation were carried out. The action of the amino acids was shown to depend on pH, incubation time and the temperature of incubation. Attempts were made to find a correlation between the amino acids introduced and redox potential (Eh), pH and the activity of the cellulolytic enzymes. It was found that the addition of some amino acids to the reaction mixtures at different pH values affected the value of Eh -- which enhanced the cellulase activity.

The abundance of Azotobacter was estimated in the rhizosphere of 13 plant species from four habitats in the Botanical Garden in Poznań. The results have shown that within the particular habitats the plant exerts a pronounced influence on the abundance of Azotobacter. The morphological differences between Azotobacter populations obtained from various habitats confirm the specific effect of the plant on this bacterium.

Synthesis of auxins by fungi grown with and without tryptophan has been studied. 26 out of 30 fungal strains produced detectable amounts of auxins in tryptophan contain media. 18 strains produced but very small amounts of auxins in media without this amino acid. By means of paper chromatography, chromogenic reagents and biotest three active substances could be distinguished. They were found on the chromatograms run with isopropanol, ammonia, water (10:1:1 v/v) at Rf 0.05--0.2, 0.3--0.5 and 0.8--1.0. Most strains produced active substances with Rf 0.3--0.5.