title: Impacts of inoculum pre-treatments on enzyme activity and biochemical methane potential.
abstract: Biochemical methane potential (BMP) tests were carried out to investigate the influence of inoculum pre-treatments (filtration and pre-incubation) on methane production from cellulose and wheat straw. First-order model and Monod model were used to evaluate the kinetic constants of the BMP assays. The results demonstrated that fresh inoculum was the best option to perform BMP tests. This was evidenced by highest enzyme activity (0.11 U/mL) and highest methane yields for cellulose (356 NmL CH4/gVS) as well as wheat straw (261 NmL CH4/gVS). Besides, high biodegradability (85.8% for cellulose and 61.3% for wheat straw) was also obtained when the fresh inoculum was used. Moreover, a kinetic evaluation showed that inoculum pre-incubation at 37°C or storage at 4°C introduced a lag-time whereas the effects on hydrolysis rate were less consequent. In summary, pre-treatments affected the enzyme activity of the inoculum, and further on, significantly influenced the methane production and the degradation kinetics of the investigated substrates. It is recommended that filtration of inoculum should be avoided unless in case too large particles therein.
authors.affiliation: Department of Biotechnology, Lund University, Getingevägen 60, SE-221 00 Lund, Sweden. Electronic address: bing.wang@biotek.lu.se.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Biotechnology, Lund University, Getingevägen 60, SE-221 00 Lund, Sweden.
authors.forename: Sten
authors.initials: S
authors.lastname: Strömberg
authors.affiliation: Department of Biotechnology, Lund University, Getingevägen 60, SE-221 00 Lund, Sweden.
authors.forename: Ivo Achu
authors.initials: IA
authors.lastname: Nges
authors.affiliation: Bioprocess Control Sweden AB, Scheelevägen 22, SE-223 63 Lund, Sweden.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Nistor
authors.affiliation: Department of Biotechnology, Lund University, Getingevägen 60, SE-221 00 Lund, Sweden; Bioprocess Control Sweden AB, Scheelevägen 22, SE-223 63 Lund, Sweden.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D002482:Cellulose / Q000378:metabolism; D004798:Enzymes / Q000378:metabolism*; D005374:Filtration; D006868:Hydrolysis; D007700:Kinetics; D008697:Methane / Q000378:metabolism*; D013696:Temperature; D014908:Triticum / Q000737:chemistry / Q000378:metabolism
chemical_list: D004798:Enzymes; D002482:Cellulose; D008697:Methane
keywords: Anaerobic digestion; Biochemical methane potential; Biodegradation; Enzyme activity; Kinetic parameters; Pre-treatment