Bacterial α-diglucoside metabolism: perspectives and potential for biotechnology and biomedicine.

In a competitive microbial environment, nutrient acquisition is a major contributor to the survival of any individual bacterial species, and the ability to access uncommon energy sources can provide a fitness advantage. One set of soluble carbohydrates that have attracted increased attention for use in biotechnology and biomedicine is the α-diglucosides. Maltose is the most well-studied member of this class; however, the remaining four less common α-diglucosides (trehalose, kojibiose, nigerose, and isomaltose) are increasingly used in processed food and fermented beverages. The consumption of trehalose has recently been shown to be a contributing factor in gut microbiome disease as certain pathogens are using α-diglucosides to outcompete native gut flora. Kojibiose and nigerose have also been examined as potential prebiotics and alternative sweeteners for a variety of foods. Compared to the study of maltose metabolism, our understanding of the synthesis and degradation of uncommon α-diglucosides is lacking, and several fundamental questions remain unanswered, particularly with regard to the regulation of bacterial metabolism for α-diglucosides. Therefore, this minireview attempts to provide a focused analysis of uncommon α-diglucoside metabolism in bacteria and suggests some future directions for this research area that could potentially accelerate biotechnology and biomedicine developments. KEY POINTS: • α-diglucosides are increasingly important but understudied bacterial metabolites. • Kinetically superior α-diglucoside enzymes require few amino acid substitutions. • In vivo studies are required to realize the biotechnology potential of α-diglucosides.