苹果酸—乳酸发酵能量产生机理

Mechanism for Energy Derivation from Malolactic Fermentation

苹果酸 乳酸发酵 (MLF)是现代葡萄酒酿造工艺中重要的生物降酸手段。MLF是L 苹果酸在乳酸菌的苹果酸 乳酸酶催化下转变成L 乳酸的酶促反应过程 ,该过程没有底物水平的磷酸化 ,但在MLF过程中苹果酸确实能够刺激细菌的比生长速率 ,增加细菌生物量。进一步的研究表明 ,代谢能的产生并非由于苹果酸的脱羧反应 ,而主要源于跨膜的L 苹果酸摄入和 (或 )L 乳酸的流出 ,从而产生跨膜质子电动势 (pmf) (一小部分能量可能由L 苹果酸的代谢中间产物丙酮酸产生 )。按照化学渗透理论 ,pmf驱动F0 F1 ATPase合成ATP用于细菌生长。本文还对苹果酸的运输机制进行了综述。

Malolactic fermentation (MLF) is a very important processing technology for deacidificaton in modern winemaking.The studies with lactic acid bacteria showed that MLF was a enzymatic reaction catalyzed by malolactic enzyme (MLE) and did not involve in substrate level phosphorylation,but the growth of malolactic bacteria were stimulated with respect to both the specific growth rate and the biomass yield during MLF as compared with those in media lacking of malate.Further studies indicated that metabolic energy mainly originated from the uptake of L malate and/or excretion of L lactate across cell membrane,which could generate protion mative force (pmf),(small part of energy maybe came from spill off of the intermediary pyruvate).According to the chemiosmotic theoery,pmf could drive F\-0F\-1 ATPase to synthesize ATP.Also in this paper ,the malate trasport system was reviewed.;