The effect of corn syrup and whey on the conversion process of CO to ethanol using Clostridium ljungdahlii. (December 2020)

• Record Type: Journal Article
• Authors: Gunay, Bensu; Azbar, Nuri; Keskin, Tugba
• Is Part Of: Chemosphere. Volume 261(2020)
• Publication Date: 2020-12
• Subjects: Syngas fermentation -- Clostridium ljungdahlii -- Ethanol production -- Medium optimization -- Whey powder -- Corn syrup; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.127734
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: CO is one of the toxic components of syngas, which is the major source of air pollution. Syngas fermentation technology has the ability to convert toxic gases into valuable biofuels, such as ethanol. Fermentative ethanol production is an important method that can be used to promote environmental protection. CO can be converted into ethanol, via the Wood–Ljungdahl pathway, using Clostridium ljungdahlii . The components of the growing medium––especially the trace-element solution and yeast extract––are the main reasons for the high costs associated with this process, however, and this especially impacts scaled-up operations. In this study, cheaper substitutes for these components were used in order to determine their effect on ethanol production. The study comprised three main parts––the optimization of CO concentration, and the substitution of corn syrup and whey powder in the process. The optimum volume of CO for ethanol production was found to be 10 mL. Corn syrup can be used instead of trace-element solution, but the use of yeast extract with the corn syrup was determined to be essential. Up to 1.4 g/L ethanol production was observed with the addition of 15 mL corn syrup. Whey powder had the advantage of being usable without yeast extract, with up to 2.5 g/L ethanol being produced from a 30-g/L concentration. The main finding was that either corn syrup or whey powder can be used as substitutes for expensive basal-medium components. Graphical abstract: Image 1 Highlights: Bioprocess cost can be reduced by replacement with nutrient rich substitutes. Trace elements and fructose can be replaced with cornsyrup. Yeast extract is essential while using cornsyrup. Nutrient rich substance enhances ethanol production yields. Whey powder can be used instead of yeast extract.