Nino Tsiklauri

Bio: Nino Tsiklauri is an academic researcher. The author has contributed to research in topics: Xylanase & Cellulase. The author has an hindex of 8, co-authored 12 publications receiving 588 citations.

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.

Lignocellulose-degrading enzyme production by white-rot Basidiomycetes isolated from the forests of Georgia

Abstract: The production of lignocellulolytic enzymes by eleven basidiomycetes species isolated from two ecosystems of Georgia was investigated for the first time under submerged (SF) and solid-state fermentation (SSF) of lignocellulosic by-products. Notable intergeneric and intrageneric differences were revealed with regard to the extent of hydrolase and oxidase activity. Several fungi produced laccase along with hydrolases in parallel with growth during the trophophase, showing that the synthesis of this enzyme is not connected with secondary metabolism. The lignocellulosic substrate type had the greatest impact on enzyme secretion. Some of the substrates significantly stimulated lignocellulolytic enzyme synthesis without supplementation of the culture medium with specific inducers. Exceptionally high carboxymethyl cellulase (CMCase, 122 U ml(-1)) and xylanase (195 U ml(-1)) activities were revealed in SF of mandarin peelings by Pseudotremella gibbosa IBB 22 and of residue after ethanol production (REP) by Fomes fomentarius IBB 38, respectively. The SSF of REP by T. pubescens IBB 11 ensured the highest level of laccase activity (24,690 U l(-1)), whereas the SSF of wheat bran and SF of mandarin peels provided the highest manganese peroxidase activity (570-620 U l(-1)) of Trichaptum biforme IBB 117. Moreover, the variation of lignocellulosic growth substrate provides an opportunity to obtain enzyme preparations containing different ratios of individual enzymes.

Lignocellulolytic Enzyme Activity During Growth and Fruiting of the Edible and Medicinal Mushroom Pleurotus ostreatus (Jacq.:Fr.) Kumm. (Agaricomycetideae)

Abstract: Cotton wastes can be converted without substrate pasteurization into value-added products, such as gourmet mushrooms, with biological efficacy up to 90% and lignocellulolytic enzymes. Edible and medicinal mushroom Pleurotus ostreatus carboxymethyl cellulase and laccase activities, extracted from both the surface and inside layers of blocks, increased during primordia and fruiting bodies development and declined rapidly after the harvest. In a study of xylanase production, it has been observed that the activity of the enzyme in inside layers of the substrate gradually increased during the 49 days (second fruiting stage) after inoculation and then gradually declined towards the end of mushroom cultivation. Fluctuations in xylanase activity in the surface layer were observed, so that maximal enzyme activities coincided with the fruiting stage of P. ostreatus development. In contrast to laccase, manganese peroxidase (MnP) activity was high during the colonization stage and declined during the first primordia and fruiting body formation stages. After this, while laccase activity decreased, MnP activity peaked at the mycelia stage in oyster mushroom development. Data on the levels of cellulase, xylanase, laccase, and MnP activity in spent mushroom substrate demonstrate that it can be used as an excellent source of these enzymes.