BioChem - DOS

CO as electron donor for efficient medium chain carboxylate production by chain elongation

Chemical engineering journal

Liu, Chao; Luo, Gang; Liu, Haopeng; Yang, Ziyi; Angelidaki, Irini; O-Thong, Sompong; Liu, Guangqing; Zhang, Shicheng; Wang, Wen

<P><B>Abstract</B></P> <P>CO is a main component of syngas produced by the thermal gasification of biomass. The biological conversion of sole CO into medium-chain carboxylates (MCCs) has attracted considerable attention, although the process has a low efficiency. The present study demonstrated a process to achieve efficient MCCs production from short-chain carboxylates (SCCs), namely, acetate and n-butyrate, with CO as electron donor. Results demonstrated that n-butyrate as an electron acceptor was superior to acetate and the control (without electron acceptor). The highest n-caproate concentration (7.7 mM) was obtained in reactor 160B, while it can reach only 2.7 and 0 mM in reactors 80A and C, respectively. The lag phase (15 days) for n-caproate production with n-butyrate as electron acceptor was significantly lower than that with acetate (90 days) or control (no n-caproate produced). The microbial community composition of chain elongation bioreactors showed that <I>Eubacterium limosum</I> was significantly positively correlated with the production of n-caproate and was found to be responsible for performing chain elongation with acetate or n-butyrate as electron acceptor and CO as electron donor. A thermodynamic model based on the metabolic pathway of <I>E. limosum</I> and demonstrating the feasibility of n-caproate production from n-butyrate and CO was established. Furthermore, the present study verified that n-butyrate is more favorable as electron acceptor with CO as electron donor to achieve chain elongation according to the trade-off between the energy harvest yields and rates.</P> <P><B>Highlights</B></P> <P> <UL> <LI> N-butyrate was more suitable for MCCs production than acetate with CO as electron donor. </LI> <LI> The highest n-caproate concentration was obtained at 160 mM n-butyrate. </LI> <LI> <I>Eubacterium limosum</I> was responsible for performing chain elongation. </LI> <LI> A thermodynamic model showed the superiority of n-caproate production from n-butyrate. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

2020

Elsevier

1385-8947

390

pp.124577

10.1016/j.cej.2020.124577

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART99483650

Chain elongation; Medium chain carboxylates; Eubacterium limosum; Carbon monoxide