Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, Ghent, 9000, Belgium.
Microb Biotechnol. 2020 Jul;13(4):1026-1038. doi: 10.1111/1751-7915.13546. Epub 2020 Mar 3.
Biological CO sequestration through acetogenesis with H as electron donor is a promising technology to reduce greenhouse gas emissions. Today, a major issue is the presence of impurities such as hydrogen sulfide (H S) in CO containing gases, as they are known to inhibit acetogenesis in CO -based fermentations. However, exact values of toxicity and inhibition are not well-defined. To tackle this uncertainty, a series of toxicity experiments were conducted, with a mixed homoacetogenic culture, total dissolved sulfide concentrations ([TDS]) varied between 0 and 5 mM and pH between 5 and 7. The extent of inhibition was evaluated based on acetate production rates and microbial growth. Maximum acetate production rates of 0.12, 0.09 and 0.04 mM h were achieved in the controls without sulfide at pH 7, pH 6 and pH 5. The half-maximal inhibitory concentration (IC ) was 0.86, 1.16 and 1.36 mM [TDS] for pH 7, pH 6 and pH 5. At [TDS] above 3.33 mM, acetate production and microbial growth were completely inhibited at all pHs. 16S rRNA gene amplicon sequencing revealed major community composition transitions that could be attributed to both pH and [TDS]. Based on the observed toxicity levels, treatment approaches for incoming industrial CO streams can be determined.
利用 H 作为电子供体进行生物 CO 捕获以减少温室气体排放是一项很有前途的技术。如今，一个主要问题是 CO 中存在杂质，如硫化氢 (H S)，因为它们已知会抑制基于 CO 的发酵中的产乙酸作用。然而，毒性和抑制的确切值尚未明确界定。为了解决这一不确定性，进行了一系列毒性实验，使用混合同型产乙酸菌培养物，总溶解硫浓度 ([TDS]) 在 0 至 5 mM 之间，pH 值在 5 至 7 之间变化。根据乙酸盐的产率和微生物生长来评估抑制程度。在没有硫化物的情况下，在 pH 值为 7、pH 值为 6 和 pH 值为 5 时，控制组的最大乙酸盐产率分别达到 0.12、0.09 和 0.04 mM·h。半抑制浓度 (IC ) 分别为 0.86、1.16 和 1.36 mM [TDS]，pH 值分别为 7、6 和 5。在 [TDS] 高于 3.33 mM 时，在所有 pH 值下，乙酸盐的产生和微生物的生长都完全受到抑制。16S rRNA 基因扩增子测序揭示了主要的群落组成转变，这可以归因于 pH 值和 [TDS]。基于观察到的毒性水平，可以确定处理即将到来的工业 CO 流的方法。
