title: Self-adaption of methane-producing communities to pH disturbance at different acetate concentrations by shifting pathways and population interaction.
abstract: To investigate the competition among acetate-utilizing microorganisms at different acetate levels, bioconversion processes of 50, 100, 150 and 200 mM acetate in the presence and absence of methanogenic inhibitor CH3F were monitored in thermophilic methanogenic system. The successive response of methane-producing community during the deteriorative and recovery phases caused by pH disturbance was analyzed. High acetate concentration (>50mM) inhibited the activity of acetoclastic methanogenesis (AM). The increasing pH (>7.5) enhanced this inhibition. The syntrophic acetate oxidizing (SAO) bacteria and hydrogenotrophic methanogens including Methanomicrobiales and Methanobacteirales were more tolerant to the stress from high acetate concentration and high pH. Resumption from alkali condition to normal pH stimulated the growth of acetate oxidizing syntrophs. The reaction rate of SAO-HM was lower than that of AM. These results point to the possibility to regenerate the deteriorated anaerobic digesters by addition of acclimatized inocula rich in acetate-oxidizing syntrophs.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, PR China.
authors.forename: Liping
authors.initials: L
authors.lastname: Hao
authors.forename: Fan
authors.initials: F
authors.lastname: Lü
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Qing
authors.initials: Q
authors.lastname: Wu
authors.forename: Liming
authors.initials: L
authors.lastname: Shao
authors.forename: Pinjing
authors.initials: P
authors.lastname: He
mesh_terms: D000085:Acetates / Q000302:isolation & purification / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000187:drug effects*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology; D053898:Biosynthetic Pathways / Q000187:drug effects*; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008697:Methane / Q000096:biosynthesis*; D010084:Oxidation-Reduction / Q000187:drug effects; D013997:Time Factors
chemical_list: D000085:Acetates; D056804:Biofuels; D006859:Hydrogen; D008697:Methane