Determinação das melhores condições para produção da enzima quitinase pelo fungo Beauveria bassiana

Chitinases, enzymes produced by diverse organisms like bacteria, fungi, insects, plants, and humans, play a crucial role in degrading the biopolymer chitin. They have wide-ranging applications, including abilities to isolate protoplasts from fungi, control pathogenic fungi, treat chitinous waste, and manage disease transmission viinsects due to their chitin-degrading ability. This study focused on determining optimal conditions for chitinase production using the fungus Beauveria bassiana, acknowledging the enzyme's significant importance. The strain employed was B. bassiana 487 from Embrapa, registered in the ARSEF database. Three media (Hill, Adams, and Medium 2) were assessed with or without shrimp exoskeletons as an inducer over a 10-day period. Initial fermentation conditions included a pH of 5.5, a temperature of 28 °C, stirring at 120 rpm, and an inoculum size of 107 cells/mL. Production and enzymatic activity were evaluated, monitored for 7 days, with the tenth day dedicated to identifying optimal production conditions. Medium 2 demonstrated superior production when supplemented with the inducer, reaching its peak on the seventh day. Following the medium selection, chitinase enzymatic activity in Medium 2 with the inducer was assessed. Until the eighth day, B. bassiana 487 showed low enzyme production, with an enzymatic activity of 6.08 nmol/mL.min. A significant increase occurred on the ninth day, reaching 348.94 nmol/mL.min. High activity persisted on the tenth and eleventh days, with values of 302.45 and 264.59 nmol/mL.min, respectively. In conclusion, for enhanced chitinase production by B. bassiana 487, we recommend using Medium 2 over a 10-day fermentation period under suitable conditions.