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
International Journal of Hydrogen Energy
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.
Veeravalli, Sathyanarayanan S.; Chaganti, Subba Rao; Lalman, Jerald A.; and Heath, Daniel D.. (2014). 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. International Journal of Hydrogen Energy, 39 (19), 9994-10002.