D. Draganova*, I. Valcheva, Y. Kuzmanova, M. Naydenov
Department of Microbiology and Ecological Biotechnologies, Faculty of Plant Protection and Agroecology, Agricultural University, 4000 Plovdiv, Bulgaria (Manuscript received 14 June 2017; accepted for publication 8 August 2017)
Abstract. Cellulases and hemicellulases are amount the main hydrolytic enzymes, involved in the bioconversion of lignocellulose material by microorganisms. Filamentous fungi of the genus Trichoderma are one of the most studied and good producer of cellulases and hemicellulases. The nutrients balance, especially carbon to nitrogen ratio, is one of the main factors of the biodegradation. The ability of 37 local isolates of Trichoderma sp. to produce cellulases and xylanase were tested in solid state cultivation on wheat straw as a substrate whit two variants: 1. the straw was only moistured with destilated water (CN 80:1); 2. the C:N ratio of the straw was adjusted to 30:1 using organic nitrogen amendment. There is a significant difference in the enzymatic activity of the isolates in their cultivation on straw with CN 80 and CN 30. The highest carboxymethylcellulase (CMCase) activity at CN 80 showed T1T (110.19U/ml), and in the variant at CN 30 – TD (369.07U/ml). The highest β-glucosidase activity on both variants CN 80 and CN 30 was established for TG (2743.1U/ml – 12679.9U/ml). The highest xylanase activity at CN 80 and CN 30 was measured on T4I (21311.5U/ml – 47937.5U/ml). After ONA addition, all enzymes activities have increased several times, indicating the enhancing effect of the additive. The average activity of CMCase increased 6.1 times, the average β – glucosidase activity increased 5.1 times, while the xylanase activity increased 4.9 times for all tested isolates. The increase in activity of the investigated enzymes showed different patterns.