Document Type

Article

Publication Date

2017

Publication Title

Journal of Chemical Technology & Biotechnology

Volume

92

Issue

3

First Page

544

Last Page

551

DOI

10.1002/jctb.5032

Keywords

upflow anaerobic sludge blanket reactor, biohydrogen, organic loading rate, flux balance analysis, pyrosequencing

Abstract

BACKGROUND: Enriching hydrogen (H2)-producing bacteria by suppressing methane- producing microorganisms is a critical step in continuous biologicalH2 production. Selective inhibition ofmethanogenscanbeachievedby varying the organic loading rate (OLR) in continuous reactors. In this study, continuous H2 production was examined using mixed anaerobic cultures fed glucose in upflow anaerobic sludge blanket reactors (UASBRs) operating at 37∘C and at pH 5.0 by varying the OLR at a constant hydraulic retention time. RESULTS: A stable H2 yield of 1.64±0.04 molmol−1 glucose was obtained at OLRs from 8.6 to 12.8 g COD L−1 d−1. Increasing the OLR increased the hydrogenase flux and suppressedmethanogenesis. At high OLRs, high acetate and solvent production were associated with Clostridiaceae and Ruminococcaceae while at lowOLRs, the presence of Synergistaceae and Propionibacteriaceae were related to the production of propionate and other reduced byproducts. CONCLUSION: This study successfully demonstrated continuous H2 production using bench-scale UASBRs fed glucose. Understanding the OLR effect on H2 production and microbial interaction is important in the full-scale operation of H2 production facilities using low value feedstocks such as switch grass, corn stover and shorghum. © 2016 Society of Chemical Industry

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