title: Does the addition of proteases affect the biogas yield from organic material in anaerobic digestion?
abstract: The aim of this study was to investigate the biochemical disintegration effect of hydrolytic enzymes in lab scale experiments. Influences of enzyme addition on the biogas yield as well as effects on the process stability were examined. The addition of proteases occurred with low and high dosages in batch and semi-continuous biogas tests. The feed mixture consisted of maize silage, chicken dung and cow manure. Only very high concentrated enzymes caused an increase in biogas production in batch experiments. In semi-continuous biogas tests no positive long-term effects (100 days) were observed. Higher enzyme-dosage led to a reduced biogas-yield (13% and 36% lower than the reference). Phenylacetate and -propionate increased (up to 372 mgl(-1)) before the other volatile fatty acids did. Volatile organic acids rose up to 6.8 gl(-1). The anaerobic digestion process was inhibited.
authors.affiliation: Deutsches Biomasseforschungszentrum gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany. Electronic address: liane.mueller@dbfz.de.
authors.forename: Liane
authors.initials: L
authors.lastname: Müller
authors.affiliation: Deutsches Biomasseforschungszentrum gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Kretzschmar
authors.affiliation: Deutsches Biomasseforschungszentrum gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Pröter
authors.affiliation: Deutsches Biomasseforschungszentrum gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Liebetrau
authors.affiliation: Deutsches Biomasseforschungszentrum gemeinnützige GmbH, Torgauer Straße 116, 04347 Leipzig, Germany; Faculty of Agricultural and Environmental Sciences, University of Rostock, Rostock 18059, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Nelles
authors.affiliation: Faculty of Agricultural and Environmental Sciences, University of Rostock, Rostock 18059, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Scholwin
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D056804:Biofuels; D002417:Cattle; D002645:Chickens; D005232:Fatty Acids, Volatile; D005260:Female; D008372:Manure; D009930:Organic Chemicals; D010447:Peptide Hydrolases / Q000737:chemistry*; D012820:Silage; D003313:Zea mays
chemical_list: D056804:Biofuels; D005232:Fatty Acids, Volatile; D008372:Manure; D009930:Organic Chemicals; D010447:Peptide Hydrolases
keywords: Anaerobic digestion; Disintegration; Enzyme; Phenylacetate; Protease