Centro de Investigação em Ciências da Saúde (CICS), Instituto Superior de Ciências da Saúde-Norte/CESPU, Gandra, Portugal.
FEMS Yeast Res. 2012 May;12(3):375-81. doi: 10.1111/j.1567-1364.2012.00790.x. Epub 2012 Feb 13.
We aimed to manipulate the metabolism of Saccharomyces cerevisiae to produce lactic acid and search for the potential influence of acid transport across the plasma membrane in this process. Saccharomyces cerevisiae W303-1A is able to use l-lactic acid but its production in our laboratory has not previously been detected. When the l-LDH gene from Lactobacillus casei was expressed in S. cerevisiae W303-1A and in the isogenic mutants jen1∆, ady2∆ and jen1∆ ady2∆, all strains were able to produce lactic acid, but higher titres were achieved in the mutant strains. In strains constitutively expressing both LDH and JEN1 or ADY2, a higher external lactic acid concentration was found when glucose was present in the medium, but when glucose was exhausted, its consumption was more pronounced. These results demonstrate that expression of monocarboxylate permeases influences lactic acid production. Ady2 has been previously characterized as an acetate permease but our results demonstrated its additional role in lactate uptake. Overall, we demonstrate that monocarboxylate transporters Jen1 and Ady2 are modulators of lactic acid production and may well be used to manipulate lactic acid export in yeast cells.
我们旨在操纵酿酒酵母的代谢以生产乳酸，并寻找在此过程中质膜跨膜酸转运的潜在影响。酿酒酵母 W303-1A 能够使用 l-乳酸，但在我们实验室中以前未检测到其生产。当来自干酪乳杆菌的 l-LDH 基因在酿酒酵母 W303-1A 及其同基因突变株 jen1∆、ady2∆ 和 jen1∆ ady2∆ 中表达时，所有菌株都能够生产乳酸，但在突变株中产量更高。在持续表达 LDH 和 JEN1 或 ADY2 的菌株中，当培养基中存在葡萄糖时，发现外部乳酸浓度更高，但当葡萄糖耗尽时，其消耗更为明显。这些结果表明，单羧酸转运蛋白的表达影响乳酸的生产。Ady2 先前被表征为乙酸转运蛋白，但我们的结果表明其在乳酸摄取中具有额外的作用。总的来说，我们证明了单羧酸转运蛋白 Jen1 和 Ady2 是乳酸生产的调节剂，并且可能很好地用于操纵酵母细胞中的乳酸外排。
