Deep Solid Fermentation Of Trichoderma Asperellum THGY-01 And Evaluation Of Its Biocontrol Application

Trichoderma sp.is a biocontrol fungus that widely used in the control of plant diseases.T.asperellum THGY-01 was used as the experimental strain in this study.The nutrient and culture conditions of solid fermentation were optimized and different thicknesses of solid culture materials and fermentation models were explored and then developed technology of solid aeration fermentation,which solved the bottleneck problem of low sporulation of Trichoderma,and capacity of spore production of the unit of solid materials was improved.Finally,the study evaluated the control efficiency of T.asperellum on root rot disease of tobacco Fusarium commune.The main results were as follows:1.The solid fermentation nutritional conditions of Trichoderma sp.were optimized.The spore production under certain conditions was predicted through the single factor design of fermentation conditions and response surface optimization analysis,which the indicator was the sporulation of unit mass.According to this model,the experiment verified the optimal conditions for solid fermentation of the strain THGY-01 of Trichoderma as follows:the volume ratio of Bran and chaff was 7:3,the concentration of glucose was 2.61%,the concentration of urea was 2.16%,and the concentration of potassium dihydrogen phosphate was 2.77%.The amount of spore production of the strain THGY-01 could be up to 4.52×108 per gram after 120 hours’ fermentation under the condition that the initial water content was 50%,inoculum size was 20%,the culture temperature was 28℃.2.Effects of different solid thickness and fermentation models on the sporulation of Trichoderma were explored.Effects on the spore production of Trichoderma by different thickness of solid material and fermentation models were compared and the results showed that:when using the shallow disk fermentation model,fermentation was sufficient only on superficial layer,but the sporulation amount was only 0.56×107 per gram after 120 hours’ fermentation in 5 cm from the surface,the amount of total sporulation was 1.26×109 per gram under this model.And then the honeycomb coal fermentation model was developed,using the model,the yield of solid fermentation of Trichoderma was significantly increased,the total amount of sporulation reached to 2.34×109 per gram after 120 hours of fermentation,even in 5 cm depth of solid material,and the amount of sporulation was 9.1×108 per gram.A series of fermentation model of aeration were developed based on its aerobic characteristics.The total amount of sporulation could reach 4.88×109 per gram after 120 hours’ fermentation by using the model of oxygen generator when flow rate of the oxygen was 4 L/min and the hole distance of the aeration tube was 1 cm.In order to improve the pressure of the aeration tube,the oxygen generator was replaced by oxygen tank and improved the model.The total amount of sporulation could reach to 6.72×109 per gram after 120 hours’ fermentation when the oxygen pressure was 0.3 MPa,the flow rate was 3 L/min,and the hole distance of the aeration tube was 4 cm.Consider the various factors,such as the cost and equipment factors;a model of air compressor aeration fermentation was developed,the amount of sporulation could reached to 6.47×109 per gram after 120 hours’ fermentation when the air pressure was 0.4 MPa,the flow rate was 4 L/min,and the hole distance of the aeration tube was 3 cm.The model of aeration model fermentation could solved the practical problem that the greater the fermentation thickness of Trichoderma sp.was,the less amount of sporulation was.3.The inhibitory effects of T.asperellum on pathogen of tobacco root rot disease was measured.The antagonistic effects of T.asperellum on F.commune were measured by confrontation in the petri dish F.commune was significantly inhibited by T.asperellum,its antagonistic grade reached grade I on the 7th day;The inhibitory effects of the volatile substances of the strain on F.commune was measured when using the button culture model,its inhibitory rate was up to 54.5%on the 7th day;The inhibitory effects of the non-volatile substances of the strain on F.commune was measured when using the disc filter model,its inhibitory rate was up to 63.8%on the 7th day.4.The effects of T.asperellum on the control of tobacco root rot disease were evaluated by pots experiment.The effects of T.asperellum on the control of tobacco root rot of F.commune was evaluated through pots inoculation test.The disease of tobacco plants inoculated with F.commune was severe,the incidence of the disease was 30%,and the disease index was 20.4.However,the disease of tobacco plants inoculated with F.commune first,and tobacco plants inoculated with T.asperellum 5 days later were less severe.The incidence of disease was 17%,the disease index was 6.3 and the relative control effects was 69.1%.