Determination of prebiotic utilisation capability of potential probiotic Bacillus velezensis FS26 through in silico and in vitro approaches

Abstract

Prebiotics are substrates that can increase bacterial growth while also benefiting the host. The presence of enzymes responsible for hydrolysing the glycosidic bond in the prebiotic structure is critical for evaluating the prebiotic's use by the bacterial strain. In silico analysis of bacterial genomes is a method for predicting the hydrolysing enzymes that cleave the glycosidic link in prebiotic structures. Furthermore, in vitro validation must be performed to further analyse and evaluate the bacterial ability to utilise prebiotics. Thus, this study aims to investigate the ability of potential probiotic Bacillus velezensis FS26 to utilise prebiotics using in silico and in vitro techniques. B. velezensis FS26 genome analysis has shown the presence of glycosidase hydrolase enzymatic family that are capable of hydrolysing α- and β-glycosidic bonds in polysaccharide and oligosaccharide structures. The enzymes responsible for prebiotic utilisation were found in the bacterial genomes including α-galactosidase, fructofuranosidase, levansucrase and β-galactosidase. Furthermore, an in vitro study employing the phenol red carbohydrates assay revealed that B. velezensis FS26 can utilise the prebiotics lactulose, raffinose, and inulin, with comparable results to the probiotic Lactiplantibacillus plantarum ATCC 8014. Furthermore, the addition of prebiotics raffinose and inulin in the nutrient broth significantly increased the growth of B. velezensis FS26 cultures in contrast with prebiotic lactulose and nutrient broth without prebiotics. The agreement of in silico and in vitro results indicates the promising capability of B. velezensis FS26 to utilise prebiotics in aquaculture, which is an important sector for maintaining global food security.