Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan; Frontier Research Center for Energy and Resource (FRCER), Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
J Biosci Bioeng. 2023 Mar;135(3):250-257. doi: 10.1016/j.jbiosc.2022.12.011. Epub 2023 Jan 16.
Hybrid biological-inorganic (HBI) systems comprising inorganic water-splitting catalysts and aerobic hydrogen-oxidizing bacteria (HOB) have previously been used for CO conversion. In order to identify new biocatalysts for CO conversion, the present study used an HBI system to enrich HOB directly from environmental samples. Three sediment samples (from a brackish water pond, a beach, and a tide pool) and two activated sludge samples (from two separate sewage plants) were inoculated into HBI systems using a cobalt phosphorus (Co-P) alloy and cobalt phosphate (CoPi) as inorganic catalysts with a fixed voltage of 2.0 V. The gas composition of the reactor headspaces and electric current were monitored. An aliquot of the reactor medium was transferred to a new reactor when significant consumption of H and CO was detected. This process was repeated twice (with three reactors in operation for each sample) to enrich HOB. Increased biomass concomitant with increased H and CO consumption was observed in the third reactor, indicating enrichment of HOB. 16S rRNA gene amplicon sequencing demonstrated enrichment of sequences related to HOB (including bacteria from Mycobacterium, Hydrogenophaga, and Xanthobacter genera) over successive sub-cultures. Finally, four different HOB belonging to the Mycobacterium, Hydrogenophaga, Xanthobacter, and Acidovorax genera were isolated from reactor media, representing potential candidates as HBI system biocatalysts.
先前已有研究使用包含无机水分解催化剂和需氧产氢菌（HOB）的混合生物-无机（HBI）系统来进行 CO 转化。为了鉴定 CO 转化的新生物催化剂，本研究使用 HBI 系统直接从环境样本中富集 HOB。将来自咸水池塘、海滩和潮池的三个沉积物样本和来自两个不同污水处理厂的两个活性污泥样本接种到 HBI 系统中，使用钴磷（Co-P）合金和磷酸钴（CoPi）作为无机催化剂，施加固定电压为 2.0 V。监测反应器顶部空间的气体组成和电流。当检测到 H 和 CO 大量消耗时，将反应器介质的一部分转移到新的反应器中。该过程重复了两次（每个样本有三个反应器在运行），以富集 HOB。在第三个反应器中观察到生物量增加，同时 H 和 CO 的消耗增加，表明 HOB 得到了富集。16S rRNA 基因扩增子测序表明，在连续的亚培养过程中，与 HOB（包括分枝杆菌属、噬氢菌属和黄单胞菌属的细菌）相关的序列得到了富集。最后，从反应器介质中分离出属于分枝杆菌属、噬氢菌属、黄单胞菌属和食酸菌属的四种不同的 HOB，它们是 HBI 系统生物催化剂的潜在候选物。
