The composition of nutrient medium and the condition of fermentation process were optimized for T.viride producing yellow pigment by three-factor Box-Behnken design and response surface analysis

which was based on the experimental results of single factor for testing bacterial strain Trichoderma viride

including the source of carbon and nitrogen

liquid loading

rotation speed

inoculum concentration

culture time and temperature etc.The results show that the optimum culture medium components and conditions are: liquid culture medium based on PDA(250 g·L-1 potato extract and 2 g·L-1 Na2HPO4)

35℃

inoculum 6%(vol)

carbon source 21.7 g·L-1  xylose

loading liquid amount 50 ml in 250 ml Erlenmeyer flask and culture time 152 h at 120 r·min-1. In the optimal conditions

the color value of yellow pigment obtained is (52.8±0.8)U·ml-1.The formation of yellow pigment would be inhibited by adding urea

ammonium sulfate

peptone

beef extract powder as the source of nitrogen.