Cascade synthesis of rare ketoses by whole cells based on L-rhamnulose-1-phosphate aldolase

• Published in: Enzyme and microbial technology 2020-02, Vol.133, p.109456-109456, Article 109456
• Main Authors: Chen, Zhou, Li, Zijie, Li, Fen, Wang, Mayan, Wang, Ning, Gao, Xiao-Dong
• Format: Article
• Language: English
• Subjects: Aldehyde-Lyases - metabolism; Biocatalysis; Biotransformation; Cascade synthesis; Escherichia coli - metabolism; Fructose - metabolism; Glyceraldehyde - metabolism; Glycerol; Glycerol - metabolism; Industrial Microbiology; Ketoses - biosynthesis; L-rhamnulose-1-phosphate aldolase; Rare ketoses; Sorbose - metabolism; Substrate Specificity; Whole-cell biocatalyst
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2019.109456

•Cascade synthesis of rare ketoses by whole cells from glycerol was developed.•The new designed biotransformation approach avoided the tedious purification of enzymes and cofactors such as ATP.•D-sorbose, D-psicose and L-fructose were efficiently produced in this system based on DHAP-dependent aldolase RhaD. Dihydroxyacetone phosphate (DHAP)-dependent aldolases demonstrate important values in the production of rare ketoses due to their unique stereoselectivities. As a specific example, we developed an efficient Escherichia coli whole-cell biocatalytic cascade system in which rare ketoses were produced from abundant glycerol and catalyzed by four enzymes based on L-rhamnulose-1-phosphate aldolase (RhaD). For the semicontinuous bioconversion in which D-glyceraldehyde was continuously added, once D-glyceraldehyde was consumed, the final yields of D-sorbose and D-psicose were 15.30 g/L and 6.35 g/L, respectively. Moreover, the maximum conversion rate and productivity of D-sorbose and D-psicose were 99% and 1.11 g/L/h at 8 h, respectively. When L-glyceraldehyde was used instead of the D-isomer, the final yield of L-fructose was 16.80 g/L. Furthermore, the maximum conversion rate and productivity of L-fructose were 95% and 1.08 g/L/h at 8 h, respectively. This synthetic platform was also compatible with other various aldehydes, which allowed the production of many other high-value chemicals from glycerol.