Title

Fermentative H-2 production using a switchgrass steam exploded liquor fed to mixed anaerobic cultures: Effect of hydraulic retention time, linoleic acid and nitrogen sparging

Document Type

Article

Publication Date

2014

Publication Title

International Journal of Hydrogen Energy

Volume

39

Issue

19

First Page

9994

Last Page

10002

DOI

10.1016/j.ijhydene.2014.04.114

Keywords

biohydrogen production; bio-hydrogen production; communities; continuous biohydrogen production; glucose; Hydraulic retention time; Mixed anaerobic cultures; Nitrogen sparging; ph; pretreatment; reactor; rice straw; sludge; substrate concentration; Switchgrass

Abstract

Fermentative hydrogen (H-2) production from a steam exploded switchgrass liquor using inhibited mixed anaerobic microbial communities was studied in upflow anaerobic sludge blanket reactors (UASBRs). Increasing the H-2 yield was accomplished by treating the inoculum with linoleic acid (LA), varying the hydraulic retention time (HRT) and sparging liquid phase with nitrogen (N-2). A maximum H-2 yield of 2.56 +/- 0.10 mol mol(-1) hexose, was obtained at a 6 h HRT in LA treated cultures sparged with N-2. Sparging or LA treatment alone was able to enhance the H-2 yield by 46 +/- 5% and 38 +/- 3%, respectively, in comparison to control cultures operating at a 6 h HRT. Of the different methods employed, N-2 sparging in combination with LA treatment proved to be more effective in enriching the H-2 producing bacteria belonging to Clostridium sp. Species belonging to Propionibacterium, Bacteroides and Eubacterium, which were associated with H-2 consumption and reduced byproducts formation, were observed in addition to Clostridium sp. in unsparged control cultures. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Comments

This is an accepted manuscript version of an aritcle whose version of record was published in:International Journal of Hydrogen Energy: http://dx.doi.org/10.1016/j.ijhydene.2014.04.114