Oral Presentation 6B-04
Genomic Biotechnology: Creation of Designer Alga for Enhanced H2 Production
James W. Lee,1* Laurens Mets,2 Dong Xu,3 Barbara R. Evans1 and Elias Greenbaum1
1
Oak Ridge National LaboratoryPost Office Box 2008
Oak Ridge, TN 37831-6194
Phone: (865) 574-1208
Fax: (865)574-1275
E-mail: Leejw@ornl.gov
2
University of Chicago3
University of Missouri-Columbia
Algal photosynthetic hydrogen (H2) production is a potentially clean energy resource. However, there are a number of technical issues that must be addressed before algal H2 production can become practical. In this presentation, we will discuss the following six physiological problems that currently challenge researchers and investors in the field of photosynthetic H2 production. These problems are: (1) restriction of photosynthetic H2 production by accumulation of a proton gradient, (2) competitive inhibition of photosynthetic H2 production by CO2, (3) requirement for bicarbonate binding at photosystem II (PSII) for efficient photosynthetic activity, (4) competitive inhibition by O2, (5) classic O2 sensitivity of the hydrogenase enzyme, and (6) light-saturation phenomenon due to large antenna size.
Potential solutions to overcome these roadblocks to photosynthetic H2 production will also be presented. The solutions are based on a novel approach that has recently been developed at Oak Ridge National Laboratory (2001 ORNL Invention Disclosure). In this approach, a "designer alga" for efficient and robust H2 production will be created by genetic insertion of hydrogenase promoter–programmed polypeptide proton channels in photosynthetic thylakoid membranes. This designer alga will be integrated also with the benefits of an O2-tolerant hydrogenase that will be created by NREL and a smaller chlorophyll antenna size that will be created by UC Berkeley. Therefore, this ORNL effort is complementary with those of NREL and UC Berkeley, and will contribute jointly with the sister NREL and UC projects to achieving a common goal of effective photobiological H2 production. By use of this approach, we will be able to simultaneously solve the six physiological problems for efficient and robust production of H2 through photosynthetic water splitting.