Isolation of Cellulolytic Lactic Acid Probiotic Bacteria from Cricket Gut and Investigation for the Antioxidant Potentials and α-Amylase Inhibition of Its Exopolysaccharide

This research aimed to isolate cellulolytic lactic acid bacteria with probiotic properties from cricket gut and to investigate the antioxidant and α-amylase inhibitory activities of the exopolysaccharide (EPS) derived from the selected bacterial strains. Cricket samples were collected from four cricket farms in Ubon Ratchathani Province. Fourteen lactic acid bacteria isolates were obtained, and their morphological characteristics and biochemical properties were examined. The isolates were then tested for their ability to digest cellulose, and only one isolate, FF02041, demonstrated cellulase enzyme production. Isolate FF02041 was further tested for its probiotic potential and showed tolerance to acid and bile salts. Morphological and biochemical characterization indicated that isolate FF02041 is similar to bacteria in the Lactobacillus group. The EPS extracted from isolate FF02041 showed the DPPH and ABTS free radical scavenging activities 15.93% and 25.59%, respectively, at 10 mg mL-1. The FRAP antioxidant activity of EPS was 21.74 ± 0.06 mg Fe2+ eq. g-1 EPS. Furthermore, EPS demonstrated α-amylase inhibitory activity; at a concentration of 10 mg mL-1, the EPS showed an inhibition rate of 49.61%, corresponding to 22.74 ± 0.09 mg AE g-1 EPS. GRAPHICAL ABSTRACT HIGHLIGHTS Isolation of Cellulolytic Lactic Acid Probiotic Bacteria from Cricket Gut