Effect of temperature and substrate on conidia yield of entomopathogenic fungi using the JKI solid-state bioreactor system.

Abstract

The growing demand for sustainable pest control has intensified the need for large-scale biopesticide production. Beauveria bassiana and Metarhizium anisopliae are widely used in Integrated Pest Management (IPM), but their production still requires more efficient, scalable methods. This study is the first to evaluate the simultaneous cultivation of B. bassiana (IBCB227) and M. anisopliae (IBCB425) in the JKI-Solid Fermenter System (JKI-SFs) under different temperatures and novel substrate combinations, including rice-barley mixes. Solid-state fermentation was conducted at 15, 20, 25, 30, and 37 °C on parboiled rice, barley, and a rice-barley mix (4:1). Optimal conidia yields were achieved at 25 °C for B. bassiana and 25-30 °C for M. anisopliae, with no sporulation at 37 °C. The rice-barley matrix enhanced production: a 194% increase in conidia yield was observed for B. bassiana and 5.8% for M. anisopliae compared to rice alone. The JKI-SFs bioreactor enabled yields up to 6.0 × 109 conidia/g dry mass without contamination and with better handling. These findings demonstrate the potential of JKI-SFs as an efficient, scalable, and contamination-free system for biopesticide production using optimized substrate strategies.