Oxygen Sensitivity of -Hydrogenases

An overall economic analysis of the system has also been performed,8 76 which is guiding the direction of research in areas that will produce cost-saving results. As a result, a new, lower cost, continuous H2-production system has been conceived, designed and tested,65 although it is still not a cost-competitive process yet. 

In order to address the low cell density issue associated with sulfur-deprived cell suspensions, cell immobilization strategies have been investigated. This resulted in an 18 times increase in the H2-production rates on a per-cell culture volume basis and a 6 times longer period of H2 production by algal cultures immobilized on glass fibers.138 Additionally, the immobilized cultures have increased productivity (2.5 times) on a per illuminated area basis, compared to cell suspensions. 

Maria L. Ghirardi, Pin Ching Maness, and Michael Seibert 

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Biophotolysis has multiple issues to solve before it can be considered practical. The issues include low light conversion efficiency and oxygen sensitivity of hydrogenase. Photofermentation also suffers from low light conversion efficiency, but it can be a nice substitute to MEC as the second-stage treatment for dark fermentation effluent. 

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