Vladimir Elisashvili

Bio: Vladimir Elisashvili is an academic researcher from University of Georgia. The author has contributed to research in topics: Laccase & Manganese peroxidase. The author has an hindex of 23, co-authored 68 publications receiving 2404 citations. Previous affiliations of Vladimir Elisashvili include Russian Academy of Sciences.

Effect of nitrogen source on lignocellulolytic enzyme production by white-rot basidiomycetes under solid-state cultivation

Abstract: The effect of additional nitrogen sources on lignocellulolytic enzyme production by four species of white-rot fungi (Funalia trogii IBB 146, Lentinus edodes IBB 363, Pleurotus dryinus IBB 903, and P. tuberregium IBB 624) in solid-state fermentation (SSF) of wheat straw and beech tree leaves was strain- and substrate-dependent. In general, the yields of hydrolytic enzymes and laccase increased by supplementation of medium with an additional nitrogen source. This stimulating effect of additional nitrogen on enzyme accumulation was due to higher biomass production. Only xylanase specific activity of P. dryinus IBB 903 and laccase specific activity of L. edodes IBB 363 increased significantly (by 66% and 73%, respectively) in SSF of wheat straw by addition of nitrogen source to the control medium. Additional nitrogen (20 mM) repressed manganese peroxidase (MnP) production by all fungi tested. The study of the nitrogen concentration effect revealed that 10 mM peptone concentration was optimal for cellulase and xylanase accumulation by P. dryinus IBB 903. While variation of the peptone concentration did not cause the change in MnP yield, elevated concentrations of this nutrient (20–40 mM) led to a 2–3-fold increase of P. dryinus IBB 903 laccase activity. About 10–20 mM concentration of NH4NO3 was optimal for cellulase and xylanase production by F. trogii IBB 146. However, neither the laccase nor the MnP yield was significantly changed by the additional nitrogen source.

Effect of growth substrate, method of fermentation, and nitrogen source on lignocellulose-degrading enzymes production by white-rot basidiomycetes

Abstract: The exploration of seven physiologically different white rot fungi potential to produce cellulase, xylanase, laccase, and manganese peroxidase (MnP) showed that the enzyme yield and their ratio in enzyme preparations significantly depends on the fungus species, lignocellulosic growth substrate, and cultivation method. The fruit residues were appropriate growth substrates for the production of hydrolytic enzymes and laccase. The highest endoglucanase (111 U ml(-1)) and xylanase (135 U ml(-1)) activities were revealed in submerged fermentation (SF) of banana peels by Pycnoporus coccineus. In the same cultivation conditions Cerrena maxima accumulated the highest level of laccase activity (7,620 U l(-1)). The lignified materials (wheat straw and tree leaves) appeared to be appropriate for the MnP secretion by majority basidiomycetes. With few exceptions, SF favored to hydrolases and laccase production by fungi tested whereas SSF was appropriate for the MnP accumulation. Thus, the Coriolopsis polyzona hydrolases activity increased more than threefold, while laccase yield increased 15-fold when tree leaves were undergone to SF instead SSF. The supplementation of nitrogen to the control medium seemed to have a negative effect on all enzyme production in SSF of wheat straw and tree leaves by Pleurotus ostreatus. In SF peptone and ammonium containing salts significantly increased C. polyzona and Trametes versicolor hydrolases and laccase yields. However, in most cases the supplementation of media with additional nitrogen lowered the fungi specific enzyme activities. Especially strong repression of T. versicolor MnP production was revealed.

The pharmacological potential of mushrooms.

Abstract: This review describes pharmacologically active compounds from mushrooms. Compounds and complex substances with antimicrobial, antiviral, antitumor, antiallergic, immunomodulating, anti-inflammatory, antiatherogenic, hypoglycemic, hepatoprotective and central activities are covered, focusing on the review of recent literature. The production of mushrooms or mushroom compounds is discussed briefly.

Microbial Extracellular Polymeric Substances: Ecological Function and Impact on Soil Aggregation.

Abstract: A wide range of microorganisms produce extracellular polymeric substances (EPS), highly hydrated polymers that are mainly composed of polysaccharides, proteins and DNA. EPS are fundamental for microbial life and provide an ideal environment for chemical reactions, nutrient entrapment and protection against environmental stresses such as salinity and drought. Microbial EPS can enhance the aggregation of soil particles and benefit plants by maintaining the moisture of the environment and trapping nutrients. In addition, EPS have unique characteristics, such as biocompatibility, gelling and thickening capabilities, with industrial applications. However, despite decades of research on the industrial potential of EPS, only a few polymers are widely used in different areas, especially in agriculture. This review provides an overview of current knowledge on the ecological functions of microbial extracellular polymeric substances (EPS) and their application in agricultural soils to improve soil particle aggregation, an important factor for soil structure, health and fertility.