Process parameters affecting the sustainability of fermentative hydrogen production: A short review

Abstract

Anaerobic fermentation is regarded as the least energy intensive method for H2 production. Extensive literature on experimental attempts to achieve the highest possible theoretical yield (e.g. 4 mol H2/mol glucose) is available. All published steady state, mixed culture studies show yields much lower than the theoretical maximums for the substrates applied. This article summarizes the influence of key process parameters (pH and buffer systems, temperature, H2 partial pressure, feed stock, and reactor configuration) on fermentative hydrogen production. The following three requirements for successful Bio-H2 fermentation in mixed cultures are identified: (1) Maintain environmental conditions for the formation of oxidized products; (2) Optimize the relationship between biomass and hydrogen yields; and (3) Maintain unfavorable conditions for hydrogen consuming organisms. Fulfilling these requirements has not yet been achieved in stable continuous cultures, and it may not be achievable do to some fundamental limitation.