Discovery of a bacterial gene cluster for deglycosylation of the toxic potato steroidal glycoalkaloids α-chaconine and α-solanine

Potato juice is a by-product of starch processing currently used as feed. However, potato proteins are an untapped source of high-protein food for human nutrition if harmful constituents notably glycoalkaloids (GAs) are detoxified. The two principle GAs found in potato are α-chaconine and α-solanine, both consisting of a solanidine aglycone with a carbohydrate side-chain. The first step in the detoxification of these compounds is removal of the trisaccharide. Whole-genome sequencing of a bacterial isolate, Arthrobacter sp. S41, that degrade completely α-chaconine and α-solanine revealed the presence of a gene cluster possibly involved in the deglycosylation of GAs. Functional characterization confirmed the enzymatic activity of the gene cluster involved in the complete deglycosylation of both α-chaconine and α-solanine. The novel enzymes described here may find value in the bioconversion of feed proteins to food proteins suitable for human nutrition.