Design and evaluation of gas fermentation systems for CO2 reduction to C2 and C4 fatty acids: Non-genetic metabolic regulation with pressure, pH and reaction time. (May 2022)

• Record Type: Journal Article
• Authors: Katakojwala, Ranaprathap; Tharak, Athmakuri; Sarkar, Omprakash; Venkata Mohan, S
• Is Part Of: Bioresource technology. Volume 351(2022)
• Publication Date: 2022-05
• Subjects: Biobased products -- Electron donor -- Nature based solution -- Semi-pilot Scale -- Wood–Ljungdahl pathway; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2022.126937
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Head space pressure enhanced metabolic activity of the biocatalyst. Fabrication of Gas Fermentation systems enabled the study at high scale operation. Buffering capabilities of the system favored higher product formation. pH 8.5 enabled high CO2 solubility and resulted in higher fatty acid production. Bioelectrochemical behavior of the biocatalyst influenced CO2 reduction efficiency. Abstract: Addressing the carbon emissions through microbial mediated fermentation is an emerging interest. Custom designed and fabricated gas fermentation (GF) systems were evaluated to optimize the headspace pressure, pH (6.5, 7.5, and 8.5), fermentation time, and substrate concentration by employing enriched homoacetogenic chemolithoautotrophs in non-genetic approach. Headspace pressure showed marked influence on the metabolic conversion of inorganic carbon to acetic and butyric acids with 26% higher productivity than the control (atmospheric pressure). Maximum volatile fatty acid (VFA) yield of 3.7 g/L was observed at alkaline pH (8.5) under 2 bar pressure at carbon load of 10 g/L, 96 h). Acetic (3.0 g/L) and butyric (0.7 g/L) acids were the major products upon conversion of 85% of the inorganic substrate. A better in-situ buffering (β = 0.048) at pH 8.5 along with higher reductive current (RCC: −4.4 mA) depicted better performance of GF towards CO2 reduction.