Critical Review on Key Approaches to Enhance Synthesis and Production of Steviol Glycosides: A Blueprint for Zero-Calorie Sweetener

Steviol glycosides (SvGls) are plant secondary metabolites belonging to the class diterpenes. SvGls naturally derived from non-calorie sugar have therapeutic properties for diabetics, carcinogens, and anti-microbials. Over the past few years, SvGls have been extensively researched because of their extraordinary sweetness without side effects. SvGls are classified into several types based on the number of sugar bases attached to the steviol. Due to the difference in glycosylation, different SvGls have different sensory properties. One of the main obstacles is the mass production of SvGls. Novel physical and chemical treatments and advanced biotechnological approaches are introduced to increase the production of SvGls. Extraction of high-purity SvGls from plants is difficult, so researchers have manipulated the metabolic pathways of engineered microorganisms for bulk production of SvGls. There are many aspects related to the biochemistry and metabolism of SvGls, but their functional relationship with the S. rebaudiana is not well understood. Thus there is a need for in-depth research in this area. This review provides the readers with an overview of the research gaps and possible promising methodologies that can be utilized in the future. To trigger more research, this review encompasses the recent developments in SvGls production and marketing.