The Separation, Identification And Spore Production By Solid State Fermentation Of Trichoderma GhanenseY01

Trichodrma spp. is one of the most promising biocontrol fungus with ability of controlling plant pathogens, widely used for agricultural production. Their biocontrol mechanism involves competition for nutrients and space, myparasitism, production of antibiosis or fungal cell wall degrading enzymes, inducing resisttance of plant on the pathogens et al. Trichoderma ghanense, an antagonistic Trichoderma strain, can effectively control rice wilt desease caused by the rot (Pythium arrhenomanes). However, researches on spore production of Trichoderma ghanense by solid state fermentation were reported rarely. This study aims at improving the spore yield of Trichoderma ghanense by optimizing the components of medium and the culture conditions for industrial applications.First, three Trichodema strains with different morphological characteristics were isolated from the compost by the method of dilution painted dish, identified as Trichoderma ghanense by the molecular biology method.And their morphological characteristics were studied.The antagonism against three common plant pathogenic gungi was investigated. As results, Trichoderma ghanense Y01and Trichoderma ghanense Y02had the obvious antagonism against phathogens. Trichoderma ghanense Y01was choosed as original strain for following studies because of its fast-growing and abundant spore production.Then, Trichoderma ghanense Y01as original strain, optimization of the solid state fermentation medium was performed to improve the spore yield in the flask. Through the single factor experiment, Plackett-Burman experiment, the steepest ascent experiment and the response surface analysis, sugar, corn steep liquor MgSO4and (NH4)2SO4were identified as the most important factors to influence the spore yield. The optimal concentration of the three factors is0.56%,0.56%,2.59%and1.50%respectively. The optimal initial water content of the medium was identified as35%and the optimal initial pH was identified as9. The highest spore yield has been achieved as3.75×109CFU/g initial dry substrate (IDS) on the optimized solid state medium, which is7.4times higher than the initial medium. Finaly, the culture of Trichoderma ghanense Y01was amplified in the tray solid state fermentation.The influences of temperature, the initial water content of medium, the medium thickness and other factors on spore yield were investigated in the tray fermentation. The results showed that the optimal culture temperature is30℃,the optimum initial water content is50%, the best medium thickness is3cm, and the best fermentation time is5d. The highest spore yield has been achieved as4.35×109CFU/g IDS on the optimized tray solid state fermentation condition, which established a good foundation for the subsequent application of industrialization.