Stevia rebaudiana (Stevia) is a plant native to South America, the leaves contain sweet components known as steviol and steviol glycosides. These compounds are allowed as food additives in the USA since 2009, and the European market since December 2011. Steviol glycosides are excellent natural alternatives for sucrose and synthetic sweeteners. The main disadvantage of commercial use of steviol glycosides is their bitter lingering aftertaste. The quality and sweetness of the steviol glycosides can be improved via transglycosylation of the C-13 terthydroxyl and the C-19 carboxylic acid functions of the steviol backbone.
The steviol glycoside rubusoside is efficiently α-glucosylated by the generally recognized as safe (GRAS) bacterium Lactobacillus reuteri 180 enzyme mutant Gtf180-ΔN-Q1140E using sucrose as a donor substrate.