title: Biogas properties and enzymatic analysis during anaerobic fermentation of Phragmites australis straw and cow dung: influence of nickel chloride supplement.
abstract: The importance of nickel (added as NiCl2) on mesophilic anaerobic fermentation of Phragmites australis straw and cow dung was demonstrated by investigating the biogas properties, pH values, organic matter degradation [chemical oxygen demand (COD)] and enzyme activities (cellulase, protease and dehydrogenase) during the fermentation process. The results showed that Ni2+addition increased the cumulative biogas yields by >18 % by improving the efficiency of first peak stage and bringing forward the second peak stage. The pH values were not significantly influenced by Ni2+addition (p > 0.05). Biogas yields were associated with variations in COD concentrations rather than momentary concentrations. At the start-up stage of fermentation (4th day), the biogas yields increased gradually together with the increase of dehydrogenase activities at elevated Ni2+concentrations when cellulase and protease activities were similar in all test groups. It is suggested that Ni2+addition was mainly dependent on the methanogenic stage. After the start-up stage, the impact of Ni2+addition on biogas production was mainly dependent on its effect on cellulase activities, rather than protease or dehydrogenase activities.
authors.affiliation: Research Center for Engineering Ecology and Nonlinear Science, North China Electric Power University, Beijing, 102206, China.|School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
authors.forename: Yonglan
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Research Center for Engineering Ecology and Nonlinear Science, North China Electric Power University, Beijing, 102206, China. rceens@ncepu.edu.cn.
authors.forename: Huayong
authors.identifier: 0000-0002-1836-0894
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Research Center for Engineering Ecology and Nonlinear Science, North China Electric Power University, Beijing, 102206, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Chai
authors.affiliation: Research Center for Engineering Ecology and Nonlinear Science, North China Electric Power University, Beijing, 102206, China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Wang
authors.affiliation: Research Center for Engineering Ecology and Nonlinear Science, North China Electric Power University, Beijing, 102206, China.
authors.forename: Xueyue
authors.initials: X
authors.lastname: Mi
authors.affiliation: Research Center for Engineering Ecology and Nonlinear Science, North China Electric Power University, Beijing, 102206, China.
authors.forename: Luyi
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
authors.forename: Maxwell Adam
authors.initials: MA
authors.lastname: Ware
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001673:Biodegradation, Environmental; D056804:Biofuels; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D002417:Cattle; D002480:Cellulase / Q000378:metabolism; D005260:Female; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D008697:Methane / Q000378:metabolism; D009532:Nickel / Q000494:pharmacology*; D010447:Peptide Hydrolases / Q000378:metabolism; D006109:Poaceae / Q000378:metabolism*
chemical_list: D056804:Biofuels; C022838:nickel chloride; D009532:Nickel; D002480:Cellulase; D010447:Peptide Hydrolases; D008697:Methane
keywords: Cellulase; Dehydrogenase; Enzyme; Nickel ion; Phragmites australis; Protease