Screening, identification and characterization of lignocellulolytic fungi from decomposing rice straw and eucalyptus stump

Abstract

The fungi from decomposing rice straw and rotten eucalyptus stumps in AmphoeMueang, Nongkhai Province were screened usingagar diffusion technique. There were 32 isolates that could hydrolyze lignocelluloses.Thoseisolates hydrolyzed cellulose and hemicellulose, but lignin oxidationwas not found.Among the fungi isolatefrom rotten eucalyptus stumps, NKU1-5, NKU1-7and NKU2-9 showed highest ability to hydrolyze hemicelluloses. The optimal temperatures for those isolate were35, 35and 25 ^oC, respectively. In addition, their growth rates were similar at 25 ^oC. Thexylanase activity and hemicelluloses hydrolysis abilityof those isolate, rice straw as substrate, were compared at 25^oC and 50% moisture content on the model of solid state fermentation. The NKU2-9 showed the highest xylanase activity (4.48 IU/ml) and hemicellulose degradation (8.29%).Those 3isolates were identified as Aspergillus sp. strain NKU1-5 (KY405016), Aspergillus sp. strain NKU1-7 (KY405017) and Curvularia sp. NKU 2-9strain (KY405018) as assessed by partial 5.8S rDNA sequences. These lignocellulolytic fungi have the potential to degrade agricultural waste to produce valuable products and to handle the waste without environmental harmful.