Conversion of (poly)phenolic compounds in food fermentations by lactic acid bacteria: Novel insights into metabolic pathways and functional metabolites

Conversion of Phytochemicals by Lactobacilli: (Phospho)-β-glucosidases Are Specific for Glucosylated Phytochemicals Rather than Disaccharides

“…While hydrolysis of glycosides of phytochemicals in food fermentations is widely documented, relatively few publications determined the substrate specificity of the enzymes involved. 10 Our study confirms and extends earlier observations 11 that CAZymes of food-fermenting lactobacilli are specific for glycosides of phytochemicals but the large number of (phospho)-β-glucosidases with documented or potential activity on phytochemicals also documents that the task of matching genotype to phenotype and substrate specificity is much greater than previously thought.…”

“…Confirming this hypothesis, the mutational disruption of (phospho)-β-glucosidases in L. acidophilus revealed that one of the enzymes is active on glucosides of the phenolic compound but does not hydrolyze disaccharides. 10 This also implies that glycosides of phytochemicals are relevant substrates in plant-associated or intestinal habitats of lactobacilli; however, to date, this was shown experimentally only for the metabolism of flavonoid glycosides by the beeassociated Lactobacillus melliventris and Lactobacillus kullabergensis. 31 Glycosyl hydrolases with known activity on glycosylated phenolic compounds also occur in vertebrate-adapted lactobacilli and in organisms such as Secundilactobacillus and Paucilactobacillus that populate hexose-depleted plant substrates.…”

“…31 Glycosyl hydrolases with known activity on glycosylated phenolic compounds also occur in vertebrate-adapted lactobacilli and in organisms such as Secundilactobacillus and Paucilactobacillus that populate hexose-depleted plant substrates. 10 Metabolism of oligo-and polysaccharides by lactobacilli has predominantly been attributed to glycosyl hydrolases, 36 the only carbohydrate-active lyase that has been characterized in lactobacilli is a N-acetylneuraminate lyase in Lp. plantarum.…”

“…8 During fermentation, phytochemicals including polyphenols are modified by the metabolic activity of fermentation microbes and by the enzymatic activity of the plant substrate. 9,10 The first step of these conversions is the hydrolysis of ester bonds by esterases and the conversion of glycosylated phytochemicals by glycosyl hydrolases and carbohydrate lyases. 10−12 Glycosylated compounds include flavonoids, the most abundant class of polyphenolic compounds in plants, glycosinolates in Brassicaceae, cyanogenic glycosides, as well as glycosylated phytosterols and alkaloids.…”

Hypoglycemic effect of Lactobacillus plantarum-fermented mulberry pomace extract in vitro and in Caenorhabditis elegans

“…Lactobacillaceae possessed a broad spectrum of enzymatic activities for the biotransformation of bioactive dietary phenolic compounds, such as esterases and glycosidases, and significantly altered the phenolic constituents of the food matrix. 33 The β-glucosidase could cleave inter-sugar linkages to release phenolic aglycon and free phenolic acids. 34 The hydrolysis of flavonoid glycosides is proposed as the first step for subsequent bacterial degradation and formation of a set of new metabolisms.…”