Conidia Production of Beauveria Bassiana in Solid Substrate Fermentation Using a Biphasic System

Abstract

Beauveria bassiana is an important entomopathogenic fungus that is widely used as a bioinsecticide around the world. Conidia production is a critical step in the production of high-quality bioinsecticide. This study investigated three liquid culture mediums and five combinations of solid substrates to enhance conidia production by B. bassiana. The fungus was isolated from infected insects in the cocoa plantation of PT. Perkebunan Nusantara XII in Kediri, East Java, Indonesia. The three culture mediums were malt extract broth (MB), potato dextrose broth (PDB), and yeast and malt extract broth (YMB). Five combinations of solid substrate were used: 100% rice, 100% maize, 75%:25% rice:maize, 50%:50% rice:maize, and 25%:75% rice:maize. The biphasic system was used in this study, in which the fungus was first grown under submerged conditions and then was allowed to conidiate in solid-state conditions. The data showed that PDB was the optimum culture medium to produce blastophore and beauvericin, the active compound that acts as a mycoinsecticide. In the selection test, 100% rice was the optimum solid substrate to produce high amounts of conidia, and the consistency and production tests yielded the same results, with conidia counts of 1.93x109, 1.78x109, and 2.08x109, respectively. In a rice storability test, B. bassiana conidia numbers remained stable for up to 105 days of storage at room temperature.
 Keywords: Beauveria bassiana, culture medium, solid-substrate, conidia, biphasic system