Screening Of Fungal Strains Research Articles

The characteristics of fungal responses to uranium mining activities and analysis of their tolerance to uranium

The influence of uranium (U) mining on the fungal diversity (FD) and communities (FC) structure was investigated in this work. Our results revealed that soil FC richness and FD indicators obviously decreased due to U, such as Chao1, observed OTUs and Shannon index (P<0.05). Moreover, the abundances of Mortierella, Gibberella, and Tetracladium were notably reduced in soil samples owing to U mining activities (P<0.05). In contrast, the abundances of Cadophora, Pseudogymnoascus, Mucor, and Sporormiella increased in all soil samples after U mining (P<0.05). Furthermore, U mining not only dramatically influenced the Plant_Pathogen guild and Saprotroph and Pathotroph modes (P<0.05), but also induced the differentiation of soil FC and the enrichment of the Animal_Pathogen-Soil_Saprotroph and Endophyte guilds and Symbiotroph and Pathotroph Saprotroph trophic modes. In addition, various fungal populations and guilds were enriched to deal with the external stresses caused by U mining in different U mining areas and soil depths (P<0.05). Finally, nine U-tolerant fungi were isolated and identified with a minimum inhibitory concentration range of 400–600 mg/L, and their adsorption efficiency for U ranged from 11.6% to 37.9%. This study provides insights into the impact of U mining on soil fungal stability and the response of fungi to U mining activities, as well as aids in the screening of fungal strains that can be used to promote remediation of U mining sites on plateaus.

Screening of Fungal Strains and Formulations of Metarhizium anisopliae to Control Phyllotreta striolata in Chinese Flowering Cabbage.

(1) Background: The cabbage flea beetle (CFB; Phyllotreta striolata) seriously damages the production of Chinese flowering cabbage (CFC; Brassica campestris L. ssp. chinensis var. utilis), which is a key leafy vegetable in South China. A large number of chemical insecticides have been sprayed to control this pest; as a result, residues and resistances are becoming an issue. It is necessary to develop biocontrol technologies to address this issue. (2) Methods: Fungal strains were selected based on bioactivity against CFB, and CFC seed pelletization with fungal conidia was subject to evaluation of control efficacy against CFB. The effective mixture of fungus and chemical insecticide was determined based on safety and joint toxicology tests. (3) Results: The screening of 103 strains from 14 genera identified the Metarhizium anisopliae strain MaGX19S02 (Ma) as the one with the highest virulence. The LC50s of Ma to CFB adult and second instar larvae on day 9 post-treatment were 3.04 × 106 and 27.2 × 106 spores/mL, respectively. In the pot test, the pelletization of CFC seeds with Ma conidia (50/25/12.5 mg in 1 g seed with 4 g fillers) demonstrated significant CFB mortalities (45-82%) 20 days after the larvae were introduced. In the field test, the seed pelletization achieved 57-81% control efficacy 14 days after sowing. Furthermore, the combination of Ma with chlorfenapyr (Chl) demonstrated a synergistic effect against CFB; based on this result, we prepared the mixture formulation of 20% Ma-Chl wettable powder (WP). The assessment of the effects of 20% Ma-Chl WP (500× diluent) against CFB revealed 93.33% mortality in the pot test and 61.3% control efficacy in the field test on day 7 post-treatment. (4) Conclusions: The findings demonstrate the potential of Ma to control CFB in the field. Seed pelletization with Ma conidia effectively controlled CFB larvae and protected CFC seedlings, wherein a mixture formulation of 20% Ma-Chl WP had substantial efficacy in controlling CFB adults. Our research provides new methods for CFB biocontrol.

Screening of Fungal Strains for Cellulolytic and Xylanolytic Activities Production and Evaluation of Brewers’ Spent Grain as Substrate for Enzyme Production by Selected Fungi

Brewer’s spent grain (BSG), the solid residue of beer production, is attracting significant attention as raw material for the production of added value substances, since until recently it was mainly used as animal feed or deposited in landfills, causing serious environmental problems. Therefore, this work aimed at developing a bioprocess using BSG as a substrate for the production of cellulases and xylanases for waste saccharification and bioenergy production. Different fungi were analyzed for their cellulolytic and xylanolytic abilities, through a first screening on solid media by assessment of fungal growth and enzyme production on agar containing carboxylmethylcellulose or xylan as the sole carbon source, respectively. The best cellulase and xylanase producers were subjected to quantitative evaluation of enzyme production in liquid cultures. Aspergillus niger LPB-334 was selected for its ability to produce cellulase and xylanase at high levels and it was cultivated on BSG by solid state fermentation. The cellulase production reached a maximum of 118.04 ± 8.4 U/g of dry substrate after 10 days of fermentation, while a maximum xylanase production of 1315.15 ± 37.5 U/g of dry substrate was reached after 4 days. Preliminary characterization of cellulase and xylanase activities and identification of the enzymes responsible were carried out.

Extracellular laccase from Monilinia fructicola: isolation, primary characterization and application.

Laccases are enzymes belonging to the family of blue copper oxidases. Due to their broad substrate specificity, they are widely used in many industrial processes and environmental bioremediations for removal of a large number of pollutants. During last decades, laccases attracted scientific interest also as highly promising enzymes to be used in bioanalytics. The aim of this study is to obtain a highly purified laccase from an efficient fungal producer and to demonstrate the applicability of this enzyme for analytics and bioremediation. To select the best microbial source of laccase, a screening of fungal strains was carried out and the fungus Monilinia fructicola was chosen as a producer of an extracellular enzyme. Optimal cultivation conditions for the highest yield of laccase were established; the enzyme was purified by a column chromatography and partially characterized. Molecular mass of the laccase subunit was determined to be near 35 kDa; the optimal pH ranges for the highest activity and stability are 4.5-5.0 and 3.0-5.0, respectively; the optimal temperature for laccase activity is 30°C. Laccase preparation was successfully used as a biocatalyst in the amperometric biosensor for bisphenol A assay and in the bioreactor for bioremediation of some xenobiotics.

Screening of fungal strains of the genus Beauveria for their ability to form endophytic relations with Phaseolus plants

Screening of 11 strains of Beauveria fungi based on their colonization rate (endophytic activity) on bean plants showed that all the cultures tested belonging either to Beauveria bassiana or Beauveria pseudobassiana are able to colonize the plants. Significant differences were revealed between the strains in their endophytic activity. Three strains of fungi with the highest endophytic activity were found and a slight growth-stimulating effect was revealed for the four strains. The relative increase in plant height was significantly higher compared to both control and other fungal cultures.

Screening of fungal strains with potentiality to hydrolyze microalgal biomass by Fourier Transform Infrared Spectroscopy (FTIR)

The use of fungi is a promising alternative for harnessing biomass after lipid extraction of microalgae since this biomass may contain relevant levels of carbohydrates that can be converted into other compounds of interest, such as sugars. Fourier Transform Infrared Spectroscopy (FTIR) has proved to be an efficient and environmentally less impacting tool for the selection of microorganisms with biotechnological potential. This study aimed to apply FTIR for the selection of fungal strains with potential to hydrolyze the biomass of the microalgae Desmodesmus subspicatus and Chlorella sp after lipid extraction. Eleven fungal strains were screened for residual biomass hydrolysis and FTIR was applied followed by multivariate analysis for the selection of filamentous fungi. The highest cell density was 28.7 × 106 cells mL-1 for Chlorella sp. and 15.8 × 106 cells mL-1 for D. subspicatus and the values of total carbohydrates content were 23.1 and 16.9%, respectively. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were useful tools to screen fungal strains. After multivariate analysis, it was possible to observe that the fungi strains that presented the greatest ability to use microalgal biomass were Penicillium G12 due to the glucose and xylose sugars obtained after lipid extraction from D. subspicatus (with sugar yield of 9.4 and 6.6%, respectively) and Trichoderma auricularis for Chlorella sp. (with sugar yield of 12.9 and 9.6%, respectively). FTIR was successfully applied to screen fungal strains.

Screening of laccase producing fungi

The screening of fungal strains on a capability to laccase synthesis was carried out and the best producers of extracellular enzyme – Stachybotris chartarum and Monilinia fructicola strains were selected. The ability of the fungus S. chartarum to produce laccase extracellularly was demonstrated in the first time, the optimal conditions for cultivation of the cells were selected, analytical quantity of a goal enzyme was obtained and the molecular mass of laccase subunit was determined (50 кDa)

Screening of fungal strains to be used as biocatalysts in bioconversion processes based on cycloaddition reactions

Screening of fungal strains to be used as biocatalysts in bioconversion processes based on cycloaddition reactions

Screening of fungal strains for amylase production

Screening of fungal strains for amylase production

Screening of fungal strains employed in the testing of plastics materials

Abstract The problems of selecting tests method and suitable challenge organisms for plastics materials are discussed. Enzyme activities of fungal strains employed in the testing of plastics have been investigated and compared with isolates of these organisms held elsewhere. The ability of organisms to clear a polycaprolactone diol medium has been assessed semiquantitatively and the results discussed in relation to the selection of organisms.

Detection and estimation of ochratoxin A.

THE recent isolation1 of ochratoxin A from Aspergillus ochraceus Wilh., which has a widespread natural distribution, made the development of a rapid method for the detection and estimation of the mycotoxin desirable. The following methods have been used during screening of fungal strains and media for toxin production.