title: Biochemical methane potential of microalgae: influence of substrate to inoculum ratio, biomass concentration and pretreatment.
abstract: The anaerobic digestion of three microalgae mixtures was evaluated at different substrate to inoculum (S/I) ratios (0.5, 1 and 3), biomass concentrations (3, 10 and 20gTS/kg) and pretreatments (thermal hydrolysis, ultrasound and biological treatment). An S/I ratio of 0.5 and 10gTS/kg resulted in the highest final methane productivities regardless of the microalgae tested (ranging from 188 to 395mL CH(4)/gVS(added)). The biological pretreatment supported negligible enhancements on CH(4) productivity, while the highest increase (46-62%) was achieved for the thermal hydrolysis. The optimum temperature of this pretreatment depended on the microalgae species. The ultrasound pretreatment brought about increases in CH(4) productivity ranging from 6% to 24% at 10,000kJ/kgTS, without further increases at higher energy inputs. The results here obtained confirmed the lack of correlation between the solubilization degree and the methane enhancement potential and pointed out that anaerobic digestion of algae after thermal pretreatment is a promising technology for renewable energy production.
authors.affiliation: Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, Valladolid, Spain.
authors.forename: M E
authors.initials: ME
authors.lastname: Alzate
authors.forename: R
authors.initials: R
authors.lastname: Muñoz
authors.forename: F
authors.initials: F
authors.lastname: Rogalla
authors.forename: F
authors.initials: F
authors.lastname: Fdz-Polanco
authors.forename: S I
authors.initials: SI
authors.lastname: Pérez-Elvira
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D018533:Biomass; D008697:Methane / Q000378:metabolism*; D058086:Microalgae / Q000254:growth & development* / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D013997:Time Factors
chemical_list: D000644:Quaternary Ammonium Compounds; D009584:Nitrogen; D008697:Methane