Technological advances in hydrogen production by Enterobacter bacteria upon substrate, luminosity and anaerobic conditions

Abstract

The enhancement of hydrogen production by Enterobacter aerogenes and Enterobacter cloacae from fermentation of carbon sources such as glucose and lactose (from cheese whey permeate) was investigated. Also, the influence of the luminosity (2200 lux) and anaerobic condition (nitrogen and argon gases) were evaluated. The assays were carried out in 50 mL reactors during 108 h. To E. aerogenes/nitrogen/luminosity condition and using glucose as substrate, H2 production (73.8 mmol/L.d) was higher than using lactose (15.5 mmol/L.d). In the dark fermentation, hydrogen yields were 1.60 mol H2/mol glucose and 1.36 molH2/mol lactose. When using E. cloacae, the light fermentation using nitrogen gas resulted in 77 mmol H2/L.d and 1.62 mol H2/mol glucose. In addition, for E. cloacae, hydrogen yields using argon gas and luminosity provided 2.39 mol/mol glucose and 2.53 mol/mol lactose. In general, butyric and acetic acid fermentation were observed and favored the target-product (H2).