Volschenk H, Viljoen M, Grobler J, Petzold B, Bauer F, Subden R E, Young R A, Lonvaud A, Denayrolles M, van Vuuren H J
Department of Microbiology, University of Stellenbosch, South Africa.
Nat Biotechnol. 1997 Mar;15(3):253-7. doi: 10.1038/nbt0397-253.
Deacidification of grape musts is crucial for the production of well-balanced wines, especially in colder regions of the world. The major acids in wine are tartaric and malic acid. Saccharomyces cerevisiae cannot degrade malic acid efficiently due to the lack of a malate transporter and the low substrate affinity of its malic enzyme. We have introduced efficient pathways for malate degradation in S. cerevisiae by cloning and expressing the Schizosaccharomyces pombe malate permease (mae1) gene with either the S. pombe malic enzyme (mae2) or Lactococcus lactis malolactic (mleS) gene in this yeast. Under aerobic conditions, the recombinant strain expressing the mae1 and mae2 genes efficiently degraded 8 g/L of malate in a glycerol-ethanol medium within 7 days. The recombinant malolactic strain of S. cerevisiae (mae1 and mleS genes) fermented 4.5 g/L of malate in a synthetic grape must within 4 days.
葡萄汁的脱酸对于酿造口感平衡的葡萄酒至关重要，在世界上较寒冷的地区尤为如此。葡萄酒中的主要酸是酒石酸和苹果酸。酿酒酵母由于缺乏苹果酸转运蛋白且其苹果酸酶的底物亲和力较低，无法有效降解苹果酸。我们通过在酿酒酵母中克隆并表达粟酒裂殖酵母苹果酸通透酶（mae1）基因以及粟酒裂殖酵母苹果酸酶（mae2）基因或乳酸乳球菌苹果酸-乳酸酶（mleS）基因，引入了苹果酸降解的有效途径。在有氧条件下，表达mae1和mae2基因的重组菌株在甘油-乙醇培养基中7天内有效降解了8 g/L的苹果酸。酿酒酵母的重组苹果酸-乳酸菌株（mae1和mleS基因）在合成葡萄汁中4天内发酵了4.5 g/L的苹果酸。
