title: Influence of Ni2+ and Co2+ on methanogenic activity and the amounts of coenzymes involved in methanogenesis.
abstract: The requirement of Ni2+ and Co2+ addition on methanogenic activity and the coenzymes involved in methanogenesis were investigated in anaerobic continuous cultivation with synthetic wastewater using acetate as the sole carbon source. Addition of Ni2+ and Co2+ to the synthetic wastewater drastically increased the maximum dilution rate of the cultivation. The concentrations of coenzymes F430 and corrinoids in the biomass increased to 0.62 micromol-Ni/g-VSS and 0.67 micromol-Co/g-VSS, respectively with the increase of the dilution rate. Methanogenic activity of the culture broth also increased with an increase of dilution rate. However, without addition of Ni2+ and Co2+, F430 and corrinoids were not detected in the biomass and methanogenic activity was only a trace level at a dilution rate of 0.025 d(-1). When the amounts of Ni2+ and Co2+ added at a dilution rate of 0.6 d(-1) were lowered in steps, the concentrations of F430 and corrinoids in the biomass and methanogenic activity decreased with decreasing amounts of Ni2+ and Co2+ added. These results suggest that Ni2+ and Co2+ were required for the methane-producing reactions via increases of coenzymes F430 and corrinoids.
authors.affiliation: Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kumamoto University, 2-39-1 Kurokami, Kumamoto-City, Kumamoto 860-8555, Japan. kida@gpo.kumamoto-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Kida
authors.forename: T
authors.initials: T
authors.lastname: Shigematsu
authors.forename: J
authors.initials: J
authors.lastname: Kijima
authors.forename: M
authors.initials: M
authors.lastname: Numaguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Mochinaga
authors.forename: N
authors.initials: N
authors.lastname: Abe
authors.forename: S
authors.initials: S
authors.lastname: Morimura