Forest Litter Fungi And Their Cellulose-degrading Activities In The Greater Khingan Mountains

Cellulose in nature is ubiquitous in diverse form,and fungi play an important role in the process of biodegrading cellulose,which is more eco-friendly.The undescribed fungi in the forest litter of the Greater Khingan Mountains need to be developed and utilized,and there are few studies on their cellulase degradation activity.In this study,we used molecular biology techniques to preliminarily identify fungi,screening novel cellulolytic fungi,optimizing their fermentation conditions for cellulase production,and further identifying the active strains.The study results are as follows:Aligning the Internal Transcribed Spacer(ITS)sequences of the tested fungi,a total of 51 fungi with the 98.5% similarity or less were found firstly,most of which belonged to Basidiomycota and Ascomycota.They belonged to 7 classes,18 orders,25 families and 46 species.Eight cellulolytic fungi had been found by the Congo red staining test.The filter paper degradation test and the determination of CMCase,Avicelase,?-glucosidase activities were further carried out,and 3 fungi were obtained.They showed better degradation effect and higher enzymes activity.Six carbon sources and 5 nitrogen sources were investigated by one-way ANOVA,screening the optimal carbon and nitrogen sources for these 3 strains,respectively.The optimal carbon sources of strains SGSF091,SGSF173,and SGSF303 were corn cob powder,avicel,and wheat bran,respectively,and all optimal nitrogen sources were peptone.Under these fermentation conditions,three cellulase activities of the strain SGSF091 were 0.70,0.62,and 0.47 U/m L,respectively.The strain SGSF173 were 0.60,0.53,and 0.19 U/m L and the strain SGSF303 were 1.03,0.52,and 0.26 U/m L.The morphology,physiology,and phylogeny of the above 3 fungi were analyzed.The results of morphological and phylogenetic analysis supported the strain SGSF303 as a new species,Arxiella longispora sp.nov..The diagnostic features are as follows: conidia long-boat-shaped,even more than 20 ?m long,average in 14–22 × 3–4 ?m.The strain SGSF091 belongs to the genus Flammeascoma,and the strain SGSF173 belongs to genus Xylaria.This study lays the foundation for the utilization of understory fungal resources in the Greater Khingan Mountains,enriching the types of fungi that can be cultivated in the forest litter,and providing 3 candidates fungal for the utilization of cellulose resources.