BioTechnology Institute, University of Minnesota, Minneapolis, Minnesota.
Department of Environmental Engineering and Earth Sciences, Clemson University, Clemson, South Carolina.
Biotechnol Bioeng. 2018 Mar;115(3):577-585. doi: 10.1002/bit.26494. Epub 2017 Dec 11.
Reports suggest that ferric iron and electron shuttling molecules will select for Fe -reducer dominated microbial biomass. We investigated the influence of the redox mediators anthraquinone-2,6-disulfonate (AQDS) and riboflavin using xylose as the sole fermentation substrate, with or without ferric iron. Electron shuttling to insoluble ferrihydrite enhanced solventogenesis, acidogenesis, hydrogen production, and xylose consumption, relative to the cells plus xylose controls in fermentations inoculated with woodland marsh sediment, wetwood disease, or raw septic liquid, over multiple transfers in 15-day batch fermentations. 16S rRNA gene based community analyses indicated that ferrihydrite alone, and AQDS/riboflavin plus ferrihydrite, immediately shifted native heterogeneous communities to those predominantly belonging to the Clostdridiales, rather than stimulating Fe respiring populations. Data were similar irrespective of the inoculum source, suggesting that Fe and/or electron shuttling compounds select for rapid proliferation of fermentative genera when fermentable substrates are present, and increases the extent of xylose consumption and solvent production.
有报道表明，高铁和电子穿梭分子将优先选择以铁还原菌为主导的微生物生物量。我们以木糖作为唯一的发酵底物，研究了氧化还原介体蒽醌-2,6-二磺酸钠（AQDS）和核黄素对铁的影响，无论是否存在高铁。与接种林地沼泽沉积物、湿木病或原始污水的发酵中仅添加细胞和木糖的对照组相比，电子穿梭到不溶性水铁矿增强了溶剂生成、产酸、产氢和木糖消耗，在 15 天批次发酵中的多次传代中都是如此。基于 16S rRNA 基因的群落分析表明，仅水铁矿和 AQDS/核黄素加铁水铁矿立即将原生异质群落转变为主要属于梭菌目（Clostridiales）的群落，而不是刺激铁呼吸种群。无论接种物来源如何，数据都相似，这表明当存在可发酵底物时，铁和/或电子穿梭化合物会选择发酵属的快速增殖，并增加木糖消耗和溶剂生成的程度。
