Advances in Biohydrogen Technologies : A Canadian Perspective
ID: 3557

Abstract: Biohydrogen has several potential advantages over other biofuels, but in order realization to realize a practical process a number of barriers limiting yields must be overcome. Recent research highlights of research on biological hydrogen production will be presented by three members of BioH2Net, a network of Canadian biohydrogen researchers. A broad perspective, ranging from use of cellulose as feedstock, enhancing yields through metabolic engineering, to complete substrate conversion using microbial electgrohydrogenesis cells will be discussed.



Dr. Levin will discuss how consolidated bioprocessing might be used. Direct cellulose fermentation by cellulolytic anaerobic bacteria offers potential to generate renewable hydrogen (H2) from inexpensive “waste” cellulosic feedstocks. The rates and yields of H2 production via direct cellulose fermentation are low and must be increased significantly if this technology is to become a viable method for generating usable H2. A much more comprehensive understanding of the relationships between gene and gene product expression, end-product synthesis patterns, and the factors that regulate carbon and electron balance, within the context of the bioreactor conditions must be achieved if we are to improve molar yields of H2 during cellulose fermentation. Strategies to increase yields of H2 production from cellulose include manipulation of carbon and electron flow via end-product inhibition (metabolic shift), metabolic engineering at the genetic level, and improvements in bioprocess engineering and bioreactor design.



Dr. Hallenbeck will focus on dark fermentative hydrogen production. Dark fermentation as a means of producing biohydrogen is attractive since a variety or readily available waste streams can be used. However, at present its practical application is prevented by the low yields obtained. Here the basic metabolisms leading to hydrogen production are outlined and current research to increase yields, either through modification of existing pathways, or by metabolic engineering to create new, higher yielding, pathways, is discussed. Inactivation of competing reactions and manipulation of culture conditions has lead to higher hydrogen yields, near those predicted by metabolic schemes. However, to be useful, hydrogen production must be increased beyond present limits. Several possibilities for surpassing those limits using metabolic engineering are presented.



Dr. Guiot will present his latest research on development of MECs, Microbial Electrohydrogenesis Cells, which are capable of driving substrate conversion tro hydrogen to completion with a modest electrical input. In these bioelectrochemical cells microbial degradation of organic matter at the anode results in a release of electrons and protons. Electrons are transferred from the anode to the cathode and protons are reduced into molecular hydrogen at the cathode, because additional energy input provided by a power supply. The main limitations associated with hydrogen production in MECs include low volumetric efficiency and the use of an expensive catalyst (platinum). We have addressed these issues by using a single chamber MEC with a three-dimensional anode and a Pd/Pt cathode; as a result we have been able to produce hydrogen from organic acids at a rate above 6 liter H2 per liter reactor per day.



Moderator: Patrick Hallenbeck, Universite de Montreal (Canada)

Presenter 1: Challenges for Biohydrogen Production via Direct Lignocellulose Fermentation
David Levin, University of Manitoba, (Canada)  [Confirmed]

Presenter 2: Metabolic Engineering for improved hydrogen yields: current status and the way forward. 
Patrick Hallenbeck, Universite de Montreal, (Canada)  [Confirmed]

Presenter 3: Biohydrogen production in a continuous flow microbial electrolysis cell with a gas phase cathode 
Serge Guiot, National Research Council Canada - Biotechnology Research Institute, (Canada)  [Confirmed]

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Panel Organizer:
Patrick Hallenbeck, Universite de Montreal, (Canada)

Why should your submission should be selected for this year’s program?
The panel speakers, internationally recognized, will provide an integrated perspective, including; utilisation of cellulosics, improvements in fermentation, and a process for stoichiometric hydrogen production.