A novel method to optimize culture conditions for biomass and sporulation of the nematophagous fungus Metarhizium anisopliae SQZ-1-21 and the entomopathogenic fungus Metarhizium anisopliae RS-4-1

Abstract

Metarhizium anisopliae is a fungus that offers great potential for the biocontrol of a wide range of host species. In this study, we developed a novel two-stage cultivation method to optimize nutrition and environmental conditions for M. anisopliae SQZ-1-21 and M. anisopliae RS-4-1. Both species were cultured on basal medium (19.00 g sucrose, 4.06 g soy peptone, 1.00 g K 2 HPO 4 , 0.50 g KCl, 0.50 g MgSO 4 , 0.01 g FeSO 4 and 17.00 g Bactor) during the first four days at room temperature, and then one of them was transferred to sporulation medium (38.09 g sucrose, 0.43 g urea, 0.05 gL-1 ZnSO 4 7H 2 O, 0.05 gL-1 CuSO 4 5H 2 O, 0.005 gL-1 H 3 BO 4 , 0.01 gL-1 MnSO 4 H 2 O, and 17.00 g Bactor), and the other was transferred to a distinct sporulation medium (9.52 g sucrose, 10.00 g soy peptone, 0.05 g/L ZnSO 4 7H 2 O, 0.05 gL-1 H 3 BO 4 and 17.00 g Bactor) for an additional four days. Basal and sporulation medium of M. anisopliae SQZ-1-21 was cultured under the following environmental conditions separately:-1.2 MPa, pH 9, 12 h light, and 29C and-1.2 MPa, pH 9, 0 h light and 29C. Basal and sporulation medium of M. anisopliae RS-4-1 was cultured under the following conditions separately:-0.3 MPa, pH 8, 24 h light, and 29C and-3.9 MPa, pH 5, 12 h light and 26C. These results provide important information on the mass production of this potential biocontrol fungus.