Photoparameters in Photofermentative Biohydrogen Production

Abstract

Research on hydrogen production by photofermentation has gained renewed interest in recent times because of its potential to generate hydrogen from renewable sources in a sustainable manner for use as an alternate energy carrier. Photofermentative bacteria use nitrogenase enzyme in the presence of adenosine triphosphate (ATP) and reducing power for hydrogen production in photobioreactors (PBRs). Depending on the pigments present in the bacteria, an optimal combination of photoparameters such as light source, intensity, duration, and wavelength have to be maintained in PBRs for efficient light-to-hydrogen conversion. In this article, over 130 literature reports on photoparameters are reviewed to aid in optimal design and operation of photobioreactors. This review includes a discussion of mathematical models reported in the literature to predict light attenuation and photochemical efficiencies of photobioreactors. As part of this study, models for predicting hydrogen evolution and predicting photochemical efficiency as a function of light wavelength and quantum requirement were developed and validated using a range of experimental data compiled from the literature. A case study is presented to illustrate how literature data could be used to size solar-based PBRs for hydrogen production. Based on this case study, it is concluded that major technological breakthroughs are required to reduce the current cost for biohydrogen production by solar-powered PBRs.