Metabolic Engineering of Saccharomyces cerevisiae to Improve Glucan Biosynthesis

Abstract

β-Glucan is a chief structural polymer in the cell wall of yeast. β-Glucan has attracted intensive attention because of its wide applications in health protection and cosmetic areas. In the present study, the β-glucan biosynthesis pathway in S. Cerevisiae was engineered to enhance β-glucan accumulation. A newly identified bacterial β-1, 6-glucan synthase GsmA from Mycoplasma agalactiae was expressed, and increased β-glucan content by 43%. In addition, other pathway enzymes were investigated to direct more metabolic flux towards the building of β-glucan chains. We found that overexpression of Pgm2 (phosphoglucomutase) and Rho1 (a GTPase for activating glucan synthesis) significantly increased β-glucan accumulation. After further optimization of culture conditions, the β-glucan content was increased by 53.1%. This study provides a new approach to enhance β-glucan biosynthesis in Saccharomyces cerevisiae.

Revealing the Potential of Lipid and β-Glucans Coproduction in Basidiomycetes Yeast

“…As a cell wall polysaccharide component, β-glucan content can account for about 10% up to 30% of the DCW and the optimization of culture conditions to achieve high cell mass plays the crucial role in biotechnological β-glucan production [ 43 ]. Several researchers reported the screening of yeast strains, metabolic engineering, and optimization of different cultivation parameters: harvesting time, media composition, osmotic stress, for achieving high cell mass, and consequently high β-glucan yield [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 ]. In the literature it was reported quite different yields for β-glucan and biomass production.…”

β-glucan: a potent adjuvant in immunotherapy for digestive tract tumors

“…Although KRE6, SKN1, FfGS6, and GsmA have been proven to participate in β-1,6-glucan synthesis, the qualitative characterization of the activities of these β-1,6-glucan synthases has not been achieved, and their protein structures have yet to be successfully resolved. Consequently, the regulatory mechanisms underlying their function remain unclear ( 56 – 58 ).…”

Yeast Synthetic Biology for the Production of Lycium barbarum Polysaccharides

“…As an ideal microbial cell factory for the production of plant natural products, S. cerevisiae is often used to characterize key genes of plant natural products. The cell wall of S. cerevisiae is mainly composed of glucan and mannose [54,55]. Furthermore, arabinose, rhamnose, xylose, and galactose can be synthesized in S. cerevisiae directly [56][57][58][59].…”

“…Overexpression of PGM2 (encoding phosphoglucomutase) and RHO1 (encoding a GTPase for activating glucan synthesis) enhanced β-Glucan production in S. cerevisiae. Optimization of the culture condition further led to a >53.1% increase [55]. Moreover, S. cerevisiae was discussed as one potential producer of chitosan, which is a β-1,4-linked glucosamine polymer [63].…”