BACILLUS SP. FROM POUZOLZIA ZEYLANICA: A PROMISING SOURCE OF ANTIOXIDANTS OPTIMIZED FOR PRACTICAL APPLICATIONS

Abstract

Endophytic bacteria are increasingly being considered as precious sources of bioactive metabolites with diverse antioxidant properties, offering significant potential for medical and food applications. This study focused on identifying and characterizing antioxidant-producing endophytes from Pouzolzia zeylanica, a traditional herbal medicine commonly used in the Mekong Delta. A total of 26 endophytic bacterial strains were screened for antioxidant activity, and Bacillus sp. PZ-R1 emerged as the most promising candidate. The secondary metabolites of this strain were extracted using ethyl acetate and optimized for antioxidant compound production using response surface methodology. The optimized fermentation conditions for antioxidant metabolite production were: 28.37 g/L glucose, an initial pH of 7.89, a temperature of 31.36°C, and an incubation period of 45.09 hours Under these conditions, the strain produced remarkable antioxidant metrics, including total phenol content (71.69 mg GAE/mL), total flavonoid content (93.61 mg QE/mL), total antioxidant capacity (184.44 mg AAE/mL), reducing power (266.59 mg AAE/mL), and ferric reducing antioxidant power activity (91.01 mg AAE/mL). These findings underscore the remarkable potential  of endophytic bacteria from P. zeylanica as a source of bioactive metabolites, paving the way for further research into their practical applications in the health and food industries.