Applied Microbiology, Lund University, P.O. Box 124, SE-211 00 Lund, Sweden.
Int J Food Microbiol. 2012 Jan 16;152(3):206-10. doi: 10.1016/j.ijfoodmicro.2011.10.007. Epub 2011 Oct 20.
Previous work on the metabolism of Lactobacillus reuteri ATCC 55730 anticipated a variability in the use of organic electron acceptors as a means to relieve metabolic redox problems. Therefore, investigations focusing on this unique metabolism of L. reuteri may reveal a basis for new probiotic properties. For instance, L. reuteri may use reactive aldehydes and ketones as electron acceptors to balance their redox metabolism, which opens the possibility to exploit this bacterium for in vivo bioreduction of deleterious compounds in the gastrointestinal tract (GIT). Herein we demonstrate that L. reuteri ATCC 55730 cultures on glucose are able to use furfural (1g/L), and hydroxymethylfurfural (HMF) (0.5g/L), as electron acceptors. The former enhances the growth rate by about 25% and biomass yield by 15%, whereas the latter is inhibitory. Furfural is stoichiometrically reduced to furfuryl alcohol by the culture. The conversion of furfural had no effect on the flux distribution between the simultaneously operating phosphoketolase and Embden-Meyerhof pathways, but initiated a flux to acetate production. In addition to furfural and HMF, cellular extracts showed potential to reoxidize NADH and/or NADPH with acrolein, crotonaldehyde, and diacetyl, indicating that conversion reactions take place intracellularly, however, utilization mechanisms for the latter compounds may not be present in this strain. The strain did not reduce other GIT-related reactive compounds, including acrylamide, glyoxal, and furan.
先前关于罗伊氏乳杆菌 ATCC 55730 代谢的研究预计，有机电子受体的使用具有多样性，这是一种缓解代谢氧化还原问题的方法。因此，针对罗伊氏乳杆菌这种独特代谢的研究可能揭示出益生菌新特性的基础。例如，罗伊氏乳杆菌可能会使用反应性醛类和酮类作为电子受体来平衡其氧化还原代谢，这为利用该细菌在体内还原胃肠道（GIT）中有害化合物开辟了可能性。在此，我们证明了在葡萄糖上培养的罗伊氏乳杆菌 ATCC 55730 能够使用糠醛（1g/L）和羟甲基糠醛（HMF）（0.5g/L）作为电子受体。前者将生长速率提高了约 25%，生物量产量提高了 15%，而后者则具有抑制作用。糠醛被培养物化学计量还原为糠醇。糠醛的转化对同时运行的磷酸酮解酶和 EMP 途径之间的通量分布没有影响，但会引发流向乙酸盐的生产。除了糠醛和 HMF 之外，细胞提取物还显示出用丙烯醛、巴豆醛和二乙酰氧化 NADH 和/或 NADPH 的潜力，这表明转化反应发生在细胞内，然而，该菌株可能不存在对后一种化合物的利用机制。该菌株不能还原其他与 GIT 相关的反应性化合物，包括丙烯酰胺、乙二醛和呋喃。
