The effect of corn syrup and whey on the conversion process of CO to ethanol using Clostridium ljungdahlii

Azbar N.

Chemosphere, cilt.261, no.127734, ss.1-9, 2020 (SCI İndekslerine Giren Dergi)


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 WoodeLjungdahl pathway, using Clostridium

ljungdahlii. The components of the growing mediumeeespecially the trace-element solution and yeast

extracteeare 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

eethe 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.