Optimization of nutritional and environmental conditions for biomass production and sporulation of entomogenous fungus Lecanicillium lecanii CA-1-G using two-stage cultivation system

摘要

Some factors on sporulation of Lecanicillium lecanii CA-1-G by one-time-at-a-factor have been studied. These factors include carbon and nitrogen sources, carbon-to-nitrogen ratios, mineral elements and vitamins together with water potentials, temperatures, dark/light cycles and pHs. On the basis of these results, together with “two-step” cultivation and orthogonal method, we optimized the culture conditions for sporulation of this fungus: inoculated with spore suspension on the basal medium ematophagous fungi (sucrose 19.00 gl-1, soy peptone 4.06 gl-1, K2HPO4 1.00 gl-1, KCl 0.50 gl-1, MgSO4 0.50 gl-1, FeSO4 0.01 gl-1and agar 13.00 gl-1) for 4 days, then transferred to sporulation medium (glucose 9.08 gl-1, soy peptone 10.00 gl-1, CuSO4·5H2O 0.01 gl-1, ZnSO4·7H2O 0.05 gl-1, CaCl2 1.00 gl-1, H3BO4 0.005 gl-1, Na2MoO4 0.005 gl-1 and agar 13.00 gl-1) for another 4 days with the environmental conditions of -7.3 MPa/pH 4/light 24 h/temperature 29°C for sporulation and -7.3 MPa/pH 3/light 12h/temperature 23°C for mass production. This research reflects on some physiology on nutrients and environmental characteristics of this fungus, and also gives the essential information for its industrialization.