It has been previously shown that the antimicrobial activity in entomopathogenic
fungi was primarily due to secondary metabolites . This was also demonstrated in our study because most of the antimicrobial
activities were present in the fungal culture filtrates . Various metabolites secreted by entomopathogenic fungi could
overcome the host immune system, modify host behavior, and defend
host resources against competing pathogens and saprophytes during
the pathogenicity process . Such metabolites as beauvericin, bassianin, oosporein, and destruxins exhibit
a wide variety of antimicrobial activities including insecticidal, anticancer,
antioxidant, and antiviral, and therefore have been suggested as potential
candidates for the development of new bioactive agents . Especially, destruxins have
been implicated as feasible, multifunctional anticancer drug candidates
for preclinical development . However,their production is limited to a few fungal species. In addition,
most entomopathogenic fungal bioactive substances have a low molecular
weight (below 1000 g/mol) and have been reported to be peptides,
but fungal bioactive substances of high molecular weight are rare
. Although more diverse biologicalactivities should be evaluated, the remarkable thermostability of the
antimicrobial substances identified makes them good candidates not
only for the development of novel biocontrol agents in plants but alsofor various industrial applications, such as in the food and livestock
industries.