Electronic Thesis and Dissertation Repository

Degree

Master of Engineering Science

Program

Chemical and Biochemical Engineering

Supervisor(s)

George Nakhla; Hisham Hafez

Abstract

Furfural inhibits biohydrogen production and numerous studies has been carried out on detoxification of furfural to enhance biofuel production. Electrochemical detoxification of furfural is a new approach to remove furfural without the degradation of sugars. However, there is limited information on the effects of the degradation products of furfural on biohydrogen production in batch tests and the impact of furfural on anode-respiring bacteria (ARB) in microbial electrolysis cells (MECs). This study investigated the effect of furfural and its derivatives, furfuryl alcohol (FFA) and 2-furoic acid (FA), on biohydrogen production. The impact of furfural on hydrogen production in MECs was also evaluated. The hydrogen yield increased from 259±11 mLH2/gCODadded to 276±8 mLH2/gCODadded by the addition of 1 g/L FA, but slightly decreased to 250±14 mLH2/gCODadded by the addition of 1 g/L FFA. More than 90% of furfural was electrochemically removed and the hydrogen yield was 196±4 mLH2/gCODadded from a mixture of glucose and electrochemically treated furfural. While 1 g/L furfural inhibited hydrogen production from glucose at a substrate-to-biomass (Sº/Xº) of 1, hydrogen yields using synthetic hydrolysate increased by up to 19% at 0.5 and 1 g/L furfural at various Sº/Xº. In continuous-flow systems, the inhibitory threshold level of furfural and furfural-to-substrate were 0.56 g furfural/L and 0.056 g furfural/g substrate. The threshold furfural concentrations in biohydrogen batch tests were 0 and 1 g/L for glucose and hydrolysate, respectively, and 2 ~ 4 g/L for a continuous-flow system. The results from acetate- and glucose-fed MECs with furfural were entirely different. The addition of 2 g/L furfural to the acetate-fed MEC did not affect the activity of ARB. In contrast, the glucose-fed MEC was inhibited by 0.7 g/L furfural and ARB were not revived.


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