National Food Institute, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
College of Food Science and Engineering, Northwest A&F University, Yangling 712100, China.
J Agric Food Chem. 2020 Apr 29;68(17):4912-4921. doi: 10.1021/acs.jafc.0c00532. Epub 2020 Apr 17.
Mannitol can be obtained as a by-product of certain heterolactic lactic acid bacteria, when grown on substrates containing fructose. , a homolactic lactic acid bacterium, normally does not form mannitol but can be persuaded into doing so by expressing certain foreign enzyme activities. In this study, we find that has an inherent capacity to form mannitol from glucose. By adaptively evolving or derivatives blocked in NAD regenerating pathways, we manage to accelerate growth on mannitol. When cells of the adapted strains are resuspended in buffer containing glucose, 4-58% of the glucose metabolized is converted into mannitol, in contrast to nonadapted strains. The highest conversion was obtained for a strain lacking all major NAD regenerating pathways. Mannitol had an inhibitory effect on the conversion, which we speculated was due to the mannitol uptake system. After its inactivation, 60% of the glucose was converted into mannitol by cells suspended in glucose buffer. Using a two-stage setup, where biomass first was accumulated by aerated culturing, followed by a nonaerated phase (static conditions), it was possible to obtain 6.1 g/L mannitol, where 60% of the glucose had been converted into mannitol, which is the highest yield reported for .
甘露醇可以从某些异型乳酸发酵菌在含有果糖的基质上生长时的副产物中获得。通常情况下，同型乳酸发酵菌 不会形成甘露醇，但可以通过表达某些外源酶活性来促使其形成甘露醇。在本研究中，我们发现 从葡萄糖中形成甘露醇的固有能力。通过适应性进化 或在 NAD 再生途径中受阻的衍生物，我们设法加速了甘露醇的生长。当适应菌株的细胞在含有葡萄糖的缓冲液中重悬时，与未适应菌株相比，有 4-58%的代谢葡萄糖转化为甘露醇。对于缺乏所有主要 NAD 再生途径的菌株，转化率最高。甘露醇对转化有抑制作用，我们推测这是由于甘露醇摄取系统所致。其失活后，悬浮在葡萄糖缓冲液中的细胞可将 60%的葡萄糖转化为甘露醇。使用两级设置，首先通过通气培养积累生物量，然后进行非通气阶段（静态条件），可以获得 6.1 g/L 的甘露醇，其中 60%的葡萄糖已转化为甘露醇，这是迄今为止报道的 产量最高的。
