Iron Oxalate Humboldtine Crystallization by Fungus Aspergillus niger

Microfungi were able to alternate solid substrate in various environments and play a noticeable role in the formation of insoluble calcium oxalate crystals in subaerial biofilms on rock surfaces. The present work describes how iron oxalate dihydrate humboldtine is acquired under the influence of the acid-producing microscopic fungus Aspergillus niger on the surface of two iron- bearing mineral substrates in vitro. Pyrrhotite and siderite rocks, as well as the products of their alteration, were investigated using a complex of analytical methods, including powder X-ray diffraction, optical microscopy, scanning electron microscopy and EDX spectroscopy. The effect of the underlying rocks with different composition and solubility and different oxidation states of iron on Fe-oxalate crystallization and on the morphology of humboldtine crystals was shown. The mechanisms of humboldtine formation were discussed. The results obtained in vitro seem promising for using fungi in bioleaching iron and other metals from processed ores and for the development of environmentally friendly biotechnologies.

Evaluating Aspergillus terreus tolerance to toxic metals

Introduction: Metal pollution is one of the major environmental problems. Some metals are toxic at very low concentrations, bioaccumulate and do not decompose to non-toxic forms. Objective: To isolate a strain of microscopic fungus in a site contaminated with toxic metals and to evaluate the tolerance to these substances. Materials and methods: Fungi were isolated from the soil of an abandoned lead mine. Tolerance index of fungi to cadmium, mercury and lead was evaluated individually at concentrations of 50, 100, 250, 350 and 500 ppm; in addition, a multimetal system (mixture) with cadmium, chromium, mercury and lead was evaluated at 4, 8, 16, 64, 80, 120, 200 and 400 ppm. The minimum inhibitory concentration (MIC) was also determined. Results and discussion: The isolated fungi were identified as Aspergillus terreus, which showed high tolerance indices for lead (0.9) at all concentrations tested and indices of 0.8 at most mercury concentrations. Cadmium was the most toxic metal; tolerance indices of 0.56 and 0.2 were observed at 50 ppm and 100 ppm, respectively. High tolerance indices (0.9) were observed in the multimetal system up to 64 ppm. MIC was greater than 500 ppm with lead and mercury, less than 250 ppm with cadmium and greater than 400 ppm with the multimetal system. Conclusion: A. terreus showed high tolerance to lead at all concentrations tested. The level of tolerance is influenced by the type of metal.

Microbiological Characteristics of Biohumus and Humin Extract

This article describes the technology of biohumus and humic extract production and their microbiological characteristics. We developed technology from cattle manure and winter wheat straw in a biodynamic fermenter to obtain biohumus. The received biohumus and the humic extract recovered therefrom were subjected to microbiological analysis. The largest physiological groups of microorganisms in the biohumus were aminoautotrophic microorganisms and ammonifiers. The influence of humic extraction on soil mycobiota was estimated which showed that 30 days after the processing of soil by humic extraction, the quantity of phytopathogenic micromycetes of genus Fusarium decreased by 3.9 times and of genus Penicillium by 1.2 times. The quantity of micromycetes of genus Aspergillus largely did not change, and the quantity of micromycetes saprophytes of genus Trichoderma increased by 2.0 times. After the humic extract treatment, the ratio of saprophytic and pathogenic groups of microscopic fungus in the soil was more than 10, which ensured their sufficient suppression. Thus, the phytosanitary state of the tested soil sample after treatment with humic extract significantly improved, which made it possible to recommend the use of humic extract for soil treatment not only as an organic fertilizer, but also for the purpose of reducing the content of phytopathogenic microscopic fungus therein. Keywords: biohumus, humic extract, soil, microorganisms, microscopic fungus, phytosanitary state

Patterns of Yeast Diversity Distribution and its Drivers in Rhizosphere Soil of Hami Melon Orchards in Different Regions of Xinjiang

Background: Yeast is an essential type of microscopic fungus found in the soil. It is vital to develop the resources of yeast to gain a better understanding of its role and potential in maintaining soil ecological balance and providing microbial resources. A special ecological environment is required for the evolution of yeast species. Xinjiang in China has unique climatic conditions with abundant melon and fruit resources. Here, we aimed to evaluate the diversity, community structure, and relationship between yeast species and environmental factors in Hami melon orchards in different regions of Xinjiang, China.Results: We used Illumina MiSeq high-throughput sequencing analysis to cluster 29,090 yeast sequences into 87 operational taxonomic units (OTUs) with 97% sequence similarity and 47 genera and 73 species. Most sequences (93.16%) belonged to the Basidiomycota; only a few (6.84%) belonged to Ascomycota. We detected 10 dominant genera and 11 dominant species with relative abundances > 1% in all sample sequences. We found that the yeast communities were significantly more diverse in the eastern Xinjiang region than in the southern and northern Xinjiang regions. The most dominant genera in the southern, eastern, and northern Xinjiang regions were Pseudozyma (54.77%), Solicoccozyma (28.6%), and Filobasidium (88.08%), respectively. Redundancy analysis (RDA) results indicated that the main factors influencing the structure of yeast in the study sites were CO, total phosphorus (TP), and total potassium (TK) of the soil.Conclusion: Our results suggest the presence of diversity and structural differences in yeast species among the southern, eastern, and northern Xinjiang regions. Eastern Xinjiang had the highest community diversity with a more even distribution of species. Differences in the geographical environment and the physicochemical properties of soils were probably the key factors driving yeast diversity and community structure.

Growth dynamics of lactic acid bacteria and dairy microscopic fungus Geotrichum candidum during their co-cultivation in milk

Production of high-quality and microbiologically safe fermented dairy products requires controlled growth and microbial interactions between lactic acid bacteria and microscopic fungi. For this purpose, detailed knowledge of their growth characteristics is needed. Therefore, the objective of this study was to analyse the growth dynamics of lactic acid bacteria of commercial DVS® FRESCO® 1000NG culture and dairy isolate of microscopic fungus Geotrichum candidum during their co-cultivation in milk. The growth dynamics of microorganisms was studied in dependence on their initial counts at 12, 15, 18, 21 and 30 °C. Growth parameters were calculated by two primary predictive models, model of Baranyi and Roberts and Huang’s model. Both models showed good ability to describe the growth dynamics of studied microorganisms, as it was confirmed by low values of RMSE index. Both microbial cultures, Fresco culture and Geotrichum candidum, showed good growth ability in milk since they reached the average maximum density of 9.50 ± 0.13 log CFU/mL and 5.85 ± 0.69 log CFU/mL ( n = 45), in order. Maximum density of studied microorganisms was not affected by their initial counts or incubation temperature. On the other hand, effect of mutual ratio of microbial initial counts and increasing temperature had a significant impact on growth dynamics.

Simultaneous lithium bioleaching and bioaccumulation from lepidolite using microscopic fungus Aspergillus niger

The leaching of lithium from lepidolite using the filamentous fungus Aspergilluss niger was examined. Two mechanisms were suggested – biochemical using citric acid as the main bioleaching agent and biomechanical through hyphae penetration confirmed by XRD and SEM analyses. The bioleaching processes were conducted at various glucose concentrations (5 – 20 g.L-1). The higher glucose concentration was, the higher Li bioleaching was observed. Li accumulation by fungal biomass played an important role in Li solubilisation from lepidolite. Totally, 11.5 mg of lithium were recovered from 1 kg of lepidolite by combination of bioleaching and bioaccumulation processes. As a result of bioleaching, the formation of new silicate phase of SiO2 was detected. According to the results, fungal bioleaching of Li from lepidolite can be a perspective way of Li recovery from hard-rock ores.

BIOLOGICAL ACTIVITY OF EXTRACTS OF PLANT HAPLOPHYLLUM PERFORATUM

The article presents the results of studies of the fungicidal and growth-stimulating activity of various parts of the ethanol extract of the plant H. perforatum. As a result of fractionation of the extract, a hexane fraction, a chloroform fraction, an ethyl acetate fraction, and a water-alcohol residue were obtained. The ethanol extract showed a high fungicidal activity against the microscopic fungus Fusarium oxisporum. The study of the growthstimulating effect on the culture of cucumbers showed a high activity of the hexane part of the extract.

Increasing Efficiency of Waste Water Treatment of Wine-Making Enterprises with Simultaneous Production of Bio Surface for Oil Industry

A method for pre-treatment of wastewater with the simultaneous production of biological surface-active substances (bio-surfactants) by deep cultivation of the microscopic fungus Hypomyces odoratus in the wastewater of a winery has been developed. In wastewater after cultivation of the fungus under aerobic conditions for 12 hours, a steady decrease in BOD was observed by 2.5 times, COD by 3 times, the content of suspended solids, sulfates, phosphates, ammonium ions, nitrates, nitrites, anionic surfactants decreased significantly substances (ACAS), cationic surfactants (CAS), wastewater in chemical composition began to approach the indicators of municipal sewage. The complexity of the composition obtained during the cultivation of the biomass fungus and the isolated exopolysaccharide contributed to a decrease in the surface tension of the oil and indicated that the fungus synthesizes the bio-surfactant complex. After contact with a 12-hour mass of fungus or exopolysaccharide obtained from biomass in highly viscous, water-flooded bituminized oil, an improvement in rheological indices was noted, and the water cut and content of paraffin deposits decreased.

SOILS OF EASTERN COAST OF BAIKAL LAKE AND THEIR ECOLOGIC-MICROBIOLOGIC CHARACTERISTIC

In this paper, we discuss new experimental data on the soils from eastern coast of the Baikal natural territory. We provide description of the soils, also the acid-alkaline conditions (from pH 5.1 to 7.9) and humus content (from 0.1 to 13.8%) were determined. The degree of biological activity determined by express method per-mitted categorizing soils as moderately and weakly active. We revealed a noticeable (on Chaddock’s scale) relationship of this activity with acid-alkaline conditions (R2 = 0.52). The quantitative-qualitative characteris-tics of soil microbiocoenoses were studied in details, revealing a high diversity of the main systematic groups of organisms. Qualitatively, the fugal component was very diverse. The specific feature of soils was the absence of the most common microscopic fungus Aspergillus niger, which is characteristic for the other Siberian soils. The investigated soils were found to be epidemiologically safe.