Improvement of biohydrogen and usable chemical products from glycerol by co-culture of Enterobacter spH1 and Citrobacter freundii H3 using Different Supports As surface Immobilization
Monday, April 28, 2014: 4:50 PM
Grand Ballroom A-C, lobby level (Hilton Clearwater Beach)
Biniam Taddele Maru, Magda Constanti, Ricardo Chimentão and Francesc Medina, Escola TÈcnica Superior D'enginyeria QuÍmica, UNIVERSITAT ROVIRA I VIRGILI, Tarragona, Spain
Glycerol is a by-product of biodiesel production which is yielded at about 10% (w/w). In the present work an improvement of the dark fermentation of glycerol was proposed by immobilization of the microorganisms on supports. Four different supports were employed: maghemite (Fe2O3), activated carbon (AC), silica gel (SiO2) and alumina (γ-Al2O3). A newly isolated co- culture of Enterobacter spH1 and Citrobacter freundii H3 was immobilized in these supports. Effect of iron species on the dark fermentation was also studied by its impregnation over AC and SiO2.

The fermentative metabolites were mainly composed by ethanol, 1,3-propanediol, lactate, H2 and CO2. Modeling using Gompertz equation for the batch dark fermentation were elucidate :

i)                    Maximum H2 productivity (mmol/L) and yield(mol H2/mol glycerol consumed) were higher in the order of: Fe/AC> AC> Fe/SiO2>SiO2 >Fe2O3> γ-Al2O3 > FC

ii)                                         Maximum Ethanol productivity (mmol/L) were higher in the order of : AC > Fe/AC > Fe/SiO2 >SiO2 > γ-Al2O3 > Fe2O3> FC and yield (mol EtOH/mol glycerol consumed)were higher in order of: γ-Al2O3 > AC>SiO2> Fe/SiO2 Fe/AC>Fe2O3> FC (

iii)                                       Maximum 1,3-propanediol productivity (mmol/L) were higher in the order of: FC > Fe/AC > Fe2O3> AC > Fe/SiO2 >SiO2 > γ-Al2O3

iv)                Maximum Lactate productivity (mmol/ L) were higher in the order of: FC > Fe2O3> Fe/AC > Fe/SiO2> AC  >SiO2 > γ-Al2O3

These results indicate that support immobilization enhance the productivity of H2 might be due to specific surface area attachment, biofilm formation of the microorganism and hydrogenase enzyme activation by iron species