title: Activity, life time and effect of hydrolytic enzymes for enhanced biogas production from sludge anaerobic digestion.
abstract: As an alternative to energy intensive physical methods, enzymatic treatment of sludge produced at wastewater treatment plants for increased hydrolysis and biogas production was investigated. Several hydrolytic enzymes were assessed with a focus on how enzyme activity and life time was influenced by sludge environments. It could be concluded that the activity life time of added enzymes was limited (<24 h) in both waste activated sludge and anaerobic digester sludge environments and that this was, for the majority of enzymes, due to endogenous protease activity. In biogas in situ experiments, subtilisin at a 1% mixture on basis of volatile solids, was the only enzyme providing a significantly increased biomethane production of 37%. However, even at this high concentration, subtilisin could not hydrolyze all available substrate within the life time of the enzyme. Thus, for large scale implementation, enzymes better suited to the sludge environments are needed.
authors: Dept. of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden.
authors: Anna
authors: A
authors: Odnell
authors: Kemira Oyj, P.O. Box 44, FI-02271, Espoo, Finland.
authors: Michael
authors: M
authors: Recktenwald
authors: Tekniska Verken i Linköping AB, P.O. Box 1500, SE-582 78, Linköping, Sweden.
authors: Katarina
authors: K
authors: Stensén
authors: Dept. of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden.
authors: Bengt-Harald
authors: BH
authors: Jonsson
authors: Dept. of Physics, Chemistry and Biology, Linköping University, SE-581 83, Linköping, Sweden; InZymes Biotech AB, Gjuterigatan 1B, SE-582 73, Linköping, Sweden. Electronic address: marka@ifm.liu.se.
authors: Martin
authors: M
authors: Karlsson
mesh_terms: D000693:Anaerobiosis; D056804:Biofuels; D019149:Bioreactors; D006868:Hydrolysis; D012722:Sewage; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D056804:Biofuels; D012722:Sewage; D062065:Wastewater
keywords: Biogas; Enzyme; Protease; Subtilisin; Wastewater treatment plant