DIPA, PROPAC. Facultad de Química, Universidad Autónoma de Querétaro, C.U. Cerro de las Campanas s/n. Col. Las Campanas, C.P. 76010 Querétaro, Qro., México.
Laboratorio de Biotecnología Microbiana del, Instituto Tecnológico Superior de Ciudad Hidalgo, Av. Ing Carlos Rojas Gutiérrez #2120, 61100 Ciudad Hidalgo, Michoacán, México.
FEMS Yeast Res. 2019 Mar 1;19(2). doi: 10.1093/femsyr/foy126.
Scheffersomyces stipitis shows a high capacity to ferment xylose, with a strong oxygen dependence to allow NAD+ regeneration. However, without oxygen regeneration of NADH occurs by other metabolic pathways like alcoholic fermentation. There are few reports about inhibitors of mitochondrial respiration and their effects on growth and fermentation. This work aimed to explore the effect of cytochrome bc1 complex inhibition by antimycin A (AA), on growth and fermentation of S. stipitis using glucose, xylose and arabinose as carbon sources, at three agitation levels (0, 125 and 250 rpm). It was possible to discriminate between respiratory and fermentative metabolism in these different conditions using xylose or arabinose. Despite the inhibition of mitochondrial respiration, the glycolytic flux was active because S. stipitis metabolized glucose or xylose to produce ATP; on 0.5 M glucose the cells yielded 17-33 g L-1 ethanol. However, more complex results were obtained on xylose, which depended upon agitation conditions where ethanol production without agitation increased up to 11 g L-1. Inhibition of respiratory chain in S. stipitis could therefore be a good strategy to improve ethanol yields.
毕赤酵母表现出很高的木糖发酵能力，强烈依赖氧气以允许 NAD+再生。然而，没有氧气时 NADH 通过其他代谢途径如酒精发酵进行再生。关于线粒体呼吸抑制剂及其对生长和发酵影响的报道很少。本工作旨在研究鱼藤酮（AA）抑制细胞色素 bc1 复合物对毕赤酵母在 0、125 和 250 rpm 三种搅拌水平下利用葡萄糖、木糖和阿拉伯糖作为碳源的生长和发酵的影响。可以使用木糖或阿拉伯糖在这些不同条件下区分呼吸和发酵代谢。尽管线粒体呼吸受到抑制，但糖酵解通量仍然活跃，因为毕赤酵母利用葡萄糖或木糖产生 ATP；在 0.5 M 葡萄糖下，细胞产生 17-33 g L-1 的乙醇。然而，在木糖上得到了更复杂的结果，这取决于搅拌条件，在没有搅拌的情况下，乙醇产量增加到 11 g L-1。因此，抑制毕赤酵母的呼吸链可能是提高乙醇产量的一种好策略。
