Author(s): Marques, Paula ; Bartolomeu, M. Lourdes ; Tomé, M. Manuela ; Neves, L. M.
Date: 2009
Persistent ID: http://hdl.handle.net/10400.9/604
Origin: Repositório do LNEG
Subject(s): Hydrogen; Glycerol; Enterobacter aerogenes; Biodiesel residues; Anaerobic process
In this work, H2 production by a strain of Enterobacter aerogenes using as substrate pure glycerol and glycerol-containing biodiesel wastes was compared. The effect of physico-chemical parameters such as temperature, initial substrate and biomass concentrations on the bio-hydrogen production efficiency was investigated. The influence of the simultaneous removal of gases produced was also evaluated The results obtained showed that a decrease of the process temperature of 37 to 30 ºC leads to both, an increase of the bio-hydrogen production rate and a decrease of the equilibrium time of the process. Furthermore, it was also observed that using 10 g/dm3 of pure glycerol or biodiesel wastes containing the same concentration of glycerol as substrate lead to very similar bio-hydrogen production yields (2.5dm3 H2/dm3 fermentation medium). This proves that the performance of the strain of E. aerogenes used was not influenced by the presence of other components than glycerol in biodiesel residues, at least for the biodiesel wastes concentration studied. Simultaneous removal of gaseous phase (mainly H2 and CO2), with its production, shows to be very efficient leading to an increase of the value of the H2/CO2 volumetric ratio, in the headspace, from 2 to 8, which is very promising regarding costs involved in the technologies for purification of H2 produced.
