The Optimal Condition and Enzyme Activity of Entomopathogenic Fungus Beauveria bassiana Using Extracted Rice Bran

Abstract

The greenhouse whitefly, Bemisia tabaci, is considered one of the most destructive pests of crops. In this study, we aimed to determine the optimal liquid culture conditions in shake flasks for maximal sporulation of Beauveria bassiana M130 using rice bran. The optimal initial pH for the spore production of B. bassiana using extracted rice bran medium was 5.2 and 28℃. The screening in shake flasks of carbon and nitrogen sources resulted in the identification of an optimal medium based on 0.5% (NH4)2SO4, with extracted rice bran 8:1. Using this medium, a production level of 2.15×10 9 spores per ml was obtained after six days from culture inoculation at 28℃ in a rotary shaking incubator at 130 rpm. In addition, the specific activities of extracellular enzymes of chitinase and protease were 4,296 μmol and 375 μmol, respectively. These results suggest that Beauveria bassiana M130 could be a biocontroller for the greenhouse whitefly.