Study On Solid State Fermentation Process For The Biocontrol Strain Of Trichoderma Harzianum FJAT-9040

In this paper, the biocontrol strain of Trichoderma harzianum FJAT-9040 and the pig litter of microbial fermentation bed for raising pigs were as original strain and main medium, respectively. The optimal growth condition of solid state fermentation, the growth conditions on different cultivation methods, the antimicrobial effect of solid state fermentation metabolites for different host pathogens of Fusarium wilt, the biocontrol effect of solid state fermentation product in eggplant and bitter gourd were studied. The results were as follows:(1) The optimization of solid state fermentation culture condition for a biocontrol strain T. harzianum FJAT-9040 was studied using single factor test and response surface methodology (RSM). The biomass of strain was used as the indicator in all tests. The results showed that the volume ratio of pig litter and wheat bran 9:1, the volume ratio of wheat grain 36.74%, the content ratio of sucrose 3.07%, the content ratio of ammonium sulfate 1.75%, initial moisture 53.68%, initial inoculation amount 7%(the initial sporulation yield of medium was 105 cfu·g-1), culture temperature 29.79℃. Under the fermention conditions, the average biomass of strain reached to 3.86×109 cfu·g-1 after 5 days.(2) Growths of the strain FJAT-9040 by the tray culture and edible fungi bacteria bag culture during the solid-state fermentation process were compared. The results showed that the biomass of strain by the tray static culture reached 6.50×107 cfu·g-1 after 10 days, when the volume ratio of medium of the tray was 10% and the intial sporulation yield of medium was 104 cfu·g-1. The biomass of strain on the edible fungi bacteria bag culture after the stirring and non-stirring inoculation could reach 4.50×108 cfu·g-1 and 9.00×107 cfu·g-1 after 20 days, respectively, when the volume ratio of medium of the edible fungi bacteria bag was 60% and the intial sporulation yield of medium was 104 cfu·g-1. Futhermore, the reation between biomass of strain and fermentation time showed that the maximum biomass of strain FJAT-9040 was 18-20 days, when the volume ratio of medium of the edible fungi bacteria bag was 60%-70% and inoculated by stirring method.(3) The solid state fermentation metabolites were extracted by three different extraction agents, including methanol agent, acetonitrile agent and pure water and then were used in measuring the antifungal bioactivity. The results displayed that these metabolites had no inhibition to 5 Fusarium oxysporum strains, including FJAT-3015, FJAT-9230, FJAT-30286, FJAT-30512, FJAT-30545. However, the spore suspension of the strain FJAT-9040 solid state fermentation product had obviously inhibitory effect on the 5 different host pathogens.(4) The nursery soil with low biological fertilizer of the strain FJAT-9040 could promote the growth of eggplant and bitter gourd, and had good efficiency to control Fusarium wilt of these crops in greenhouse. The results showed that the control efficiency of the crops planting in the nursery soil with the solid state fermentation product of the strain FJAT-9040, when inoculating the pathogens after 7 days was better than one inoculating simultaneously, and reached over 80% to eggplant and bitter gourd.