Fructan Biosynthesis by Yeast Cell Factories

Abstract

Fructan is a polysaccharide composed of fructose and can be classified into several types, such as inulin, levan, and fructo-oligosaccharides, based on their linkage patterns and degree of polymerization. Owing to its structural and functional diversity, fructan has been used in various fields including prebiotics, foods and beverages, cosmetics, and pharmaceutical applications. With increasing interest in fructans, efficient and straightforward production methods have been explored. Since the 1990s, yeast cells have been employed as producers of recombinant enzymes for enzymatic conversion of fructans including fructosyltransferases derived from various microbes and plants. More recently, yeast cell factories are highlighted as efficient workhorses for fructan production by direct fermentation. In this review, recent advances and strategies for fructan biosynthesis by yeast cell factories are discussed.

Exopolysaccharides Producing Bacteria: A Review

“…Gammaproteobacteria Erwinia amylovora , the causative agent of fire blight, is also a levan producer [ 234 ]. Several recombinant E. coli and yeasts were developed to study the biochemistry of levan synthesis by cloning and expression of levansucrase genes from L. mesenteroides and B. amyloliquefaciens [ 264 , 265 , 266 , 267 , 268 , 269 ].…”

Fructooligosaccharides (FOS) Production by Microorganisms with Fructosyltransferase Activity

“…Depicting the fact that plants and microorganisms can produce β(2→6) or β(2→1) linkages, microbial fructans are characterized by DP larger than 20,000 fructosyl units [73]. In addition, microbial systems are more efficient than vegetal systems for FOS production since microbes can produce these molecules with a single multifunctional enzyme [74]. In microbes, the FFase first catalyzes the hydrolysis of sucrose, and subsequently, it can perform fructosyltransferase activity, depending on the cellular conditions and microbial species.…”

“…Plant inulin is not heavier than 10 4 Da, while microbial inulin is usually heavier than 10 6 Da [124]. However, inulosucrases have not been employed at an industrial production scale because their FOS production yield in wild bacteria is rather low [74]. Thus, most of these enzyme genes are expressed in other microorganisms.…”