National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
J Agric Food Chem. 2024 Mar 6;72(9):4858-4868. doi: 10.1021/acs.jafc.3c09216. Epub 2024 Feb 20.
is a safe lactic acid bacterium widely used in dairy fermentations. Normally, its main fermentation product is lactic acid; however, can be persuaded into producing other compounds, e.g., through genetic engineering. Here, we have explored the possibility of rewiring the metabolism of into producing pyruvate without using genetic tools. Depriving the thiamine-auxotrophic and lactate dehydrogenase-deficient strain RD1M5 of thiamine efficiently shut down two enzymes at the pyruvate branch, the thiamine pyrophosphate (TPP) dependent pyruvate dehydrogenase (PDHc) and α-acetolactate synthase (ALS). After eliminating the remaining enzyme acting on pyruvate, the highly oxygen-sensitive pyruvate formate lyase (PFL), by simple aeration, the outcome was pyruvate production. Pyruvate could be generated by nongrowing cells and cells growing in a substrate low in thiamine, e.g., Florisil-treated milk. Pyruvate is a precursor for the butter aroma compound diacetyl. Using an α-acetolactate decarboxylase deficient strain, pyruvate could be converted to α-acetolactate and diacetyl. Summing up, by starving for thiamine, secretion of pyruvate could be attained. The food-grade pyruvate produced has many applications, e.g., as an antioxidant or be used to make butter aroma.
是一种安全的乳酸细菌，广泛用于乳制品发酵。通常，其主要发酵产物是乳酸；然而，通过基因工程可以说服它产生其他化合物。在这里，我们探索了不使用遗传工具将 的代谢途径重新布线以生产丙酮酸的可能性。剥夺硫胺素营养缺陷型和乳酸脱氢酶缺陷型 RD1M5 菌株的硫胺素可以有效地关闭丙酮酸分支上的两种酶，即依赖硫胺素焦磷酸（TPP）的丙酮酸脱氢酶（PDHc）和α-乙酰乳酸合酶（ALS）。在通过简单通气消除了剩余的作用于丙酮酸的酶，即高度敏感的丙酮酸甲酸裂解酶（PFL）后，结果是产生丙酮酸。非生长细胞和在硫胺素含量低的基质（例如，用 Florisil 处理的牛奶）中生长的细胞都可以产生丙酮酸。丙酮酸是黄油香气化合物双乙酰的前体。使用缺乏α-乙酰乳酸脱羧酶的 菌株，可以将丙酮酸转化为α-乙酰乳酸和双乙酰。总之，通过使 饥饿缺乏硫胺素，可以获得丙酮酸的分泌。所生产的食品级丙酮酸有许多应用，例如用作抗氧化剂或用于制造黄油香气。
