Palm kernel meal improves the production and conidia quality of Cordyceps javanica in conventional solid-state fermentation

Abstract

Palm kernel meal was incorporated into rice, and its effect on conidiation by Cordyceps javanica under solid-state fermentation was determined. The addition of 5% palm kernel meal increased the conidial yield by up to 40%, without compromising conidia viability and hydrophobicity. In addition, conidia caused higher levels of mortality by mycosis against Diaphorina citriadults (90%), relative to conidia harvested from rice (52%). The conidia recovered from rice/palm kernel meal mixtures also retained viability greater than 90% after storage for 10 months at 4 °C, while the conidia produced on rice reached 80%. Thus, conidia produced in the presence of palm kernel meal can be consumed immediately or in the medium term. Some advantages of palm kernel meal as a co-substrate are also analyzed in the conventional production system of C. javanica. These results are attractive for improving the mycoinsecticide production process, with excellent cost-benefit and minimal changes in infrastructure and process.