Divergence and Expression Levels of Beauvericin Synthetase Gene from <i>Beauveria </i><i>b</i><i>assiana </i>Bb-882.5 in Solid State Fermentation

Beauvericin (BEA) is a mycotoxin produced by Beauveria bassiana, through a non-ribosomal peptide synthase, known as beauvericin synthetase (bbBeas). BEA has a wide variety of biological activities, including insecticide, antimicrobial, antifungal, and antitumor. It cannot be produced by chemical synthesis, so solid-state fermentation (SSF) is an adequate strategy for its production. SSF has demonstrated high productivity of bioactive compounds (i.e., secondary metabolites) that exceed production in submerged fermentation. This study evaluates the expression levels of the bbBeas gene in solid-state fermentation using shrimp shells as a substrate. Four B. bassiana strains were employed and molecularly identified. A fragment of bbBeas gene was sequenced and analyzed to examine expression levels on SSF. Only amplified in two of four strains identified as B. bassiana due to variability in the gene. The highest bbBeas gene expression occurred on day 9 of SSF compared with days 6 and 12. Based on these results, the expression levels of the beauvericin synthase gene in the SSF allow us to identify the moment when there is the highest production of beauvericin in the solid culture and serve as a parameter for its subsequent scaling up of its production, as well as of other secondary metabolites.