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

Investigations were made on the extracellular polysaccharides production by a hydrocarbon assimilating yeast. The yeast Candida lipolytica was grown on two different media containing n-hexadecane as the sole carbon source. Polymeric materials precipitated from the culture medium with ethanol were determined gravimetrically at various growth periods. The hydrolysis of the precipitated material and their chromatographic analysis revealed the presence of mannose, glucose and galactose in the yeast extract-containing medium. The proportions of these sugars differed at various growth periods. The hydrolysates of the polymers of the yeast extract-free medium contained more xylose than those of the yeast extract containing medium.

Gibberellin-like substances were found to be produced by fungi isolated from mycorrhizae of pine. Among the isolates studied gibberellin-like substances producers were most numerous among the Basidiomycetes forming ectotrophic mycorrhiza and among non-sporulating fungi forming no mycorrhiza. In most strains the gibberellin-like subtances were elaborated after 10--20 days of incubation. The Rf values of the gibberellin-like compounds were different in various strains, but in most of them substances showing gibberellin activity appeared on the chromatograms run with benzene, acetic acid (10:3 v/v) at Rf 0.2--0.6.

It has been found that during algal blooms in an eutrophic lake occurs elimination and selection of bacteria. In this period a strong decrease in number of bacteria in the water was observed. The effect of the antibacterial substances produced by algae on the growth and respiration of bacteria isolated from the lake was investigated. The bloom forming algae were found to produce substances inhibiting the growth and respiration of Gram positive bacteria. Gram negative rods were resistant to the action of these substances. The algal substances inhibited also degradation of organic matter in the lake but only in the euphotic zone.

Studies were conducted on the eutrophic Mikołajskie Lake in the Mazurian Lake District. Over the period of investigation three maxima of the development of phytoplankton were observed: in the spring, summer and autumn. During the algal blooms the total number of bacteria in the lake strongly decreased and was between several and a dozen time smaller than between blooms. The decrease in the total number of bacteria in water and the elimination of gram positive bacteria during the algal blooms is most probably caused by the production by the algae of substances inhibiting bacterial development.

Studies were conducted to determine the role of bacteria and algae in the degradation of urea in industrial waste waters. The microflora accompanying algae in continuous cultures on waste waters from the nitrogen fertilizers industry was found to include bacteria capable of intensive degradation of urea. Urea hydrolyzing bacteria are with time eliminated from the algal culture. This elimination can be attributed to algal metabolites which inhibit the development of sensitive bacteria. The Chlorella vulgaris strain used in the treatment of wast waters from the nitrogen fertilizers industry did not hydrolyse urea.

Studies were carried out on the influence of various amino acids: cysteine, cystine, methionine, alanine, serine, tryptophan, and of thiourea and hydroquinone on the activity of cellulase synthesized by four strains of Fusarium. It follows from the results obtained that the addition of amino acids, thiourea or hydroquinone to the culture media stimulates or inhibits the activity of the enzyme studied. The effect of this action depended both on the compound and the strain studied.

Interactions between Venzar and some metabolites of Bacillus ps. 72 were studied. This strain was found to produce flavonoids increasing the phytotoxicity of Venzar. Venzar action was also increased by NH4+ ions released aboundantly by the bacterial strain.

Studies were carried out on metabolic activity of 480 bacterial isolates on 9 substrates. All bacterial isolates studied except one utilized the casamino acids. Also with casamino acids the highest oxygen uptake values were obtained. Among the carbohydrates, glucose was most frequently utilized by the planktonic bacteria. Bacteria isolated from water of the various lakes differed in their metabolic activity as well as in the capability of utilizing the individual substrates. The capability of attacking by the bacteria the substrates applied depended largely upon the time of their isolation.