Bioproduction of acetic acid from carbon dioxide as single substrate and zero valent iron (ZVI) by clostridia. (April 2022)

• Record Type: Journal Article
• Authors: Bayar, Büşra; Veiga, María C.; Kennes, Christian
• Is Part Of: Journal of CO₂ utilization. Volume 58(2022)
• Publication Date: 2022-04
• Subjects: Zero valent iron -- Anaerobic corrosion -- Clostridium -- Acetogenesis -- Carbon dioxide; Carbon dioxide -- Periodicals; Carbon dioxide -- Environmental aspects -- Periodicals; Carbon dioxide mitigation -- Periodicals; Carbon dioxide; Carbon dioxide -- Environmental aspects; Carbon dioxide mitigation; Periodicals; 628.53205
• DOI: 10.1016/j.jcou.2022.101915
• Languages: English
• ISSNs: 2212-9820

Abstract

Abstract: Developing innovative bioprocess strategies for carbon capture and utilization has been a major focus of research over the past decade as a way of creating a more resilient world. In this study, zero-valent iron (ZVI) was utilized to generate hydrogen, which was then utilized as an electron donor for CO2 reduction by either Clostridium aceticum or Clostridium carboxidivorans . For this bioprocess, an early acidic condition in the reactors facilitated more hydrogen production and thereby more acetic acid accumulation, in contrast to later acidification, elucidating the role of pH in ZVI-CO2 bioconversion. Acetic acid was produced as single end product of the process in both batch bottle studies with no pH control as well as in reactor studies with pH regulation. This is, to the best of our knowledge, the first report on selective pure CO2 bioconversion to acetic acid by clostridia, with ZVI. In order to minimize costs, scrap iron rather than pure ZVI can be used for scaling-up. By lowering the pH to 6.6 for C. aceticum, in reactor studies with 75 g/L ZVI, some ethanol production (125 mg/L) was also observed, besides acetic acid. In reactor studies, a maximum acetic acid concentration of about 2 g/L was obtained at ZVI concentrations of 50 and 75 g/L. Thus, ZVI dosage and medium pH have a major effect on the metabolites generated during CO2 utilization. Graphical Abstract: ga1 Highlights: Zero Valent Iron (ZVI), generating H2, has been successfully used for CO2 reduction. Acidogenic Clostridium spp. have been employed for CO2 bioconversion. Around 2 g/L acetic acid and 125 mg/L ethanol were produced from CO2 . 25 g/L ZVI was optimal for maintaining optimal pH with H2 production in bottle assays. Reactors with pH-control and ZVI improved the anaerobic CO2 bioconversion process.