The field of synthetic biology
The field of synthetic
biology is rapidly
growing and evolving as
it establishes itself
in the scientific
community. Consequently,
the emergence of
synthetic biology has been
increasingly reported in
the press of different
countries. At this early
stage, it is worthwhile
to note that the
coverage of synthetic
biology varies from
country to country;
with some countries
emphasizing potential
risks or benefits,
others focusing on future
applications, and still
others examining the
social and ethical
concerns that might arise as
the technology is developed.
BioHydrogen Generation by Genetically Engineered
Microorganisms
Engineering a Direct Pathway for Hydrogen Generation
James Swartz, Professor, Chemical Engineering; Alfred M. Spormann, Associate
Professor, Civil and Environmental Engineering, Biological Sciences, and Geological and
Environmental Sciences; Chia-Wei Wang, Postdoctoral Researcher, Chemical
Engineering; and Marcus Boyer and Keith Gneshin, Ph.D. Candidate Graduate
Researchers, Chemical Engineering
Introduction
The longterm goal for this project is to develop efficient and economical technology
for the biological conversion of solar energy into molecular hydrogen. The first portion
of the project (Part I) seeks to develop an organism/bioreactor system employing a
genetically engineered organism that is effective in the DIRECT conversion of sunlight to
hydrogen. The organism will use a shuttle protein, ferredoxin, to transfer electrons from
the reaction of water photolysis to the hydrogenase enzyme.
The following diagram (Figure 1) shows that this pathway is simple and short and
therefore offers attractive conversion efficiencies. The photosystem of a bacterium
such as Synechocystis captures sunlight and splits water to generate molecular oxygen,
protons, and mobilized electrons. These electrons are transferred to an electron carrying
protein, ferredoxin. We propose to introduce into the cyanobacterium a new hydrogenase
enzyme that will accept the electrons from ferredoxin and combine them with the protons
to make molecular hydrogen. However, the first and major problem is that existing
hydrogenase enzymes are inactivated by molecular oxygen. Thus, the initial focus is to
evolve a highly active hydrogenase to be resistant to inactivation by molecular oxygen.
