Title: Processes and electron flow in a microbial electrolysis cell bioanode fed with furanic and phenolic compounds

Abstract

Furanic and phenolic compounds are problematic compounds resulting from the pretreatment of lignocellulosic biomass for biofuel production. Microbial electrolysis cell (MEC) is a promising technology to convert furanic and phenolic compounds to renewable H2. The objective of the research presented here was to elucidate the processes and electron equivalents flow during the conversion of two furanic (furfural, FF; 5-hydroxymethyl furfural, HMF) and three phenolic (syringic acid, SA; vanillic acid, VA; 4-hydroxybenzoic acid, HBA) compounds in the MEC bioanode. Cyclic voltammograms of the bioanode demonstrated that purely electrochemical reactions in the biofilm attached to the electrode were negligible. Instead, microbial reactions related to the biotransformation of the five parent compounds (i.e., fermentation followed by exoelectrogenesis) were the primary processes resulting in the electron equivalents flow in the MEC bioanode. A mass-based framework of substrate utilization and electron flow was developed to quantify the distribution of the electron equivalents among the bioanode processes, including biomass growth for each of the five parent compounds. Using input parameters of anode efficiency and biomass observed yield coefficients, it was estimated that more than 50% of the SA, FF, and HMF electron equivalents were converted to current. In contrast, only 12 and 9% of VA andmore » HBA electron equivalents, respectively, resulted in current production, while 76 and 79% remained as fermentation end products not further utilized in exoelectrogenesis. For all five compounds, it was estimated that 10% of the initially added electron equivalents were used for fermentative biomass synthesis, while 2 to 13% were used for exoelectrogenic biomass synthesis. The proposed mass-based framework provides a foundation for the simulation of bioanode processes to guide the optimization of MECs converting biomass-derived waste streams to renewable H2.« less

Authors:

Zeng, Xiaofei ^[1]; Borole, Abhijeet P. ^[2]; Pavlostathis, Spyros G.  ^[1]

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+ Show Author Affiliations

1. Georgia Inst. of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division; Univ. of Tennessee, Knoxville, TN (United States). Bredesen Center for Interdisciplinary Research and Education

Publication Date:

Tue Mar 20 00:00:00 EDT 2018

Research Org.:

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1468054

Alternate Identifier(s):

OSTI ID: 1474700

Grant/Contract Number:  

AC05-00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

Environmental Science and Pollution Research International

Additional Journal Information:

Journal Volume: 25; Journal Issue: 1; Journal ID: ISSN 0944-1344

Publisher:

Springer

Country of Publication:

United States

Language:

English

Subject:

09 BIOMASS FUELS; Lignocellulosic biomass; Microbial electrolysis cell; Electron balance; Fermentation; Exoelectrogenesis; H2