Effect Of Liquid Fermentation Factors And Deforming Agent On Conidial Production By Trichoderma Asperellum Strain Tr148c

A strain of Trichoderma asperellum-Tr148c isolated from a soil sample by Wanlihua Bio-Tech Company was used to study the effect of the factors of nutrient sources(carbon and nitrogen)?initial pH?temperature?rotation of speed?volumes of loaded liquid and inoculum on the production of conidial spores of Tr 148c during the fermentation process.Potato dextrose broth(PDB)was initially used as a basic culture medium to test each of the individual factor and the orthogonal method was then utilized to have a 3-level-with-4-factor test.The results showed that the highest production of conidial spores(2.0x108cfu/ml)was obtained after 144 h liquid cultivation with an optimal combination of the factors within a formula during the fermentation process,which are the nitrogen and carbon sources of mannitol:30 g/L and yeast powder:1 g/L,respectively;initial pH:6;temperature:30?;rotation of speed:200 r/min;volumes of loaded liquid and inoculums:150 ml/500 mland 4%(v/v),respectively.To screen a deforming agent used in a liquid fermentation process which has no side effects on production of conidial spores of Trichoderma asperellum strain Tr148c,0.01%?0.04%?0.07%(v/v)of each of 10 deforming agents was respectively added into medium of potato dextrose agar(PDA).The growth inhibitory rates of Tr148c were significantly lower(P?0.05)in the media with the deforming agents of natural oil(soybean oil),polyether(GPE-633,GP-633)and organic silicon(L-101-a,L-104-a)compared to the others.Deforming tests of fermented liquid with 5 selected agents were conducted and found that the time and ability of deforming with GPE-633,L-101a and L-104-a respectively were significantly less and stronger(P?0.05)respectively compared to the other two.Liquid fermentation for spore production in 10 L and 750 L fermentors with GPE-633,L-101a and L-104-a were tested.When deforming effect met the requirements of fermentation process under the same conditions,the usage and side effects on production of Trl48c conidial spores of/with L-104a were significantly less than and smaller than(P<0.05)those with GPE-633 and L-104-a respectively.Optimization of fermentation process finally be amplified to 10 1 fermentation tank,Tr148c ultimately conidium production meet expected requirements(2.0x10~8cfu/ml).