Directed Evolution for Bioprocess Intensified Low-Carbon Bio fuels Generation

Completed

Hydrogen and Fuel Cells(Hydrogen, Hydrogen production)

Basic and strategic applied research
Applied Research and Development

ENGINEERING AND TECHNOLOGY (Chemical Engineering)

Not Cross-cutting

Professor PC Wright
Chemical and Process Engineering
University of Sheffield

3

Carbon Trust

01 April 2003

30 July 2004

16 months

£51,248

Yorkshire & Humberside

Professor PC Wright, Chemical and Process Engineering, University of Sheffield

Project Contact, Department of Chemical Engineering, University of Connecticut, USA
Project Contact, Intelligent Energy
Project Contact, Accelrys Ltd

The purpose of this project was, through targeted amino acid substitutions and molecular biology, to directly evolve a bacterial hydrogenase to produce an increase in hydrogen production of up to several orders of magnitude, with a greatly increased oxygen tolerance (hydrogenases are oxygen sensitive), and overall higher stability. It was initially planned to test this step-change in performance in a bioreactor, to assess potential large-scale production for a future hydrogen economy.

Currently, a number of limitations exist for the photosynthetic production of hydrogen from microbial sources. Traditional hydrogen-producing micro-organisms such as cyanobacteria exhibit relatively low energy conversion efficiencies and low hydrogen generation rates. Additionally, there is inherent instability in production from these organisms over time owing to various inhibitory factors. Furthermore, the enzymes responsible are naturally oxygen-sensitive and denature in even micro-aerobicconditions. In order to overcome these inherent limitations, modern genetic techniques and computer technologies, such as protein evolution and bioinformatics techniques, have been investigated in this research project. As it took considerably longer than planned to isolate a hydrogenase expressing cyanobacterial clone, it was not possible to select subsequent 'mutants' with enhanced hydrogen production potential and thus test their performance in a photobioreactor. The research therefore focused on the single goal of generating a hydrogenase- containing expression vector. Now that the presence of several such clones has been successfully proved, the remaining steps in this research programme could be taken forward at some future date. The probability is high for successfully generating recombinant strains of bacteria which would produce greater amounts of hydrogen than previously recorded. The project has shown that for the first time it is possible to develop successfullya mutant clone of Escherichia coli containing genes isolated from a hydrogen-producing cyanobacterium. E. coli is potentially more advantageous for hydrogen production as it has an increased biomass doubling rate. This could translate into a greater amount of hydrogen production, thus overcoming a major production bottleneck

01/01/07