Natural and medical sciences

2021 Issue №1

On the study of yeasts consortia ethanol producing abilities

Abstract

The production of bioethanol from non-food feedstock is considered to be a promising alternative to conventional ethanol production from food crops. However, a number of significant technological drawbacks does not allow the industrial production of bioethanol. There is the problem of screening the most effective microorganisms-producers in particular. Due to multicomponent composition of substrate, the use of several strains of microorganisms is considered to be more effective than that of one strain. Thus, the aim of the study is to select yeast consortia capable of cocultivation, and to analyze their ability to produce ethanol. According to the aim of the study, the analysis was carried out to determine the biocompatibility of some ethanologenic microorganisms from the All-Russian collection of industrial microorganisms. The ability of ethanol generation by a yeast consortia, using the enzymatic hydrolyzate of delignified Miscanthus cellulose. The comparison of the ability of yeast consortia to generate ethanol depending on aeration conditions was made. The test samples were controlled for reducing sugars with spectrophotometry, while the resulting ethanol content was determined with gas chromatography. It has been found that the use of yeast consortia makes ethanol fermentation efficient, as evidenced by the significant bioconversion of reducing sugars.

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Plants of the genus Acer L. in the Kaliningrad regional dendroflora

Abstract

The results are summed up on the introduction of 70 taxa of plants of the genus Acer L. in the Kaliningrad region (since 1922). The history of the introduction of plants in the collection fund of the region, taxonomic composition, distribution in various functional objects of landscaping, protected areas and forest phytocenoses of the region, seasonal rhythm of development has been studied; Biomorphological and ecotypic structures have been identified; an assessment of environmental plasticity and the prospects for their further introduction has been carried out. It is recommended to supplement the list of cultural areas for 3 new species (A. mono Maxim., A. semenovii Regel et Herd, A. ukurunduese Trautv. et Mey.).

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Species composition of diatom complexes (Bacillariophyta) in the holocene sediments in the Curonian lagoon

Abstract

The paper presents the results of a study on species composition of diatom assemblages in a sediment core from the southwestern part of the Curonian Lagoon. There have been identified 56 species and intraspecific taxa, which belong to 35 genera. The species of Actinocyclus, Aulacoseira, Fragilariforma and Staurosira were recorded as dominant taxa in the bottom sediment samples. The studied sediments contain a large number of species, which demonstrate optimal development at a high pH value. Most of the identified species are freshwater inhabitants, less often the brackish-water species, that is due to be associated with the simultaneous influence of the continental runoff and water exchange with the Baltic Sea. The obtained data were analysed in terms of the lithologic description and radiocarbon dating in order to evaluate the environmental conditions in the studied area during the Mid- to Late Holocene (6500—3500 cal yr BP).

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