title: Anaerobic digestion of swine manure under natural zeolite addition: VFA evolution, cation variation, and related microbial diversity.
abstract: Batch experiments were carried out on anaerobic digestion of swine manure under 10 % of total solids and 60 g/L of zeolite addition at 35 °C. Four distinctive volatile fatty acid (VFAs) evolution stages were observed during the anaerobic process, i.e., VFA accumulation, acetic acid (HAc) and butyric acid (HBu) utilization, propionic acid (HPr) and valeric acid (HVa) degradation, and VFA depletion. Large decreases in HAc/HBu and HPr/HVa occurred respectively at the first and second biogas peaks. Biogas yield increased by 20 % after zeolite addition, about 356 mL/g VSadded with accelerated soluble chemical oxygen demand degradation and VFA (especially HPr and HBu) consumption in addition to a shortened lag phase between the two biogas peaks. Compared with Ca(2+) and Mg(2+) (100-300 mg/L) released from zeolite, simultaneous K(+) and NH4 (+) (580-600 mg/L) adsorptions onto zeolite particles contributed more to the enhanced biogasification, resulting in alleviated inhibition effects of ammonium on acidogenesis and methanogenesis, respectively. All the identified anaerobes could be grouped into Bacteroidetes and Firmicutes, and zeolite addition had no significant influence on the microbial biodiversity in this study.
authors.affiliation: Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Shanghai, 200433, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.forename: Chunli
authors.initials: C
authors.lastname: Wan
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.forename: Zhongfang
authors.initials: Z
authors.lastname: Lei
authors.forename: Duu-Jong
authors.initials: DJ
authors.lastname: Lee
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Joo Hwa
authors.initials: JH
authors.lastname: Tay
authors.forename: Zhenya
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D056804:Biofuels / Q000382:microbiology; D057919:Biological Oxygen Demand Analysis; D058448:Biota; D002412:Cations / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D008372:Manure / Q000382:microbiology*; D008697:Methane / Q000378:metabolism; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013552:Swine; D017641:Zeolites / Q000737:chemistry*
chemical_list: D056804:Biofuels; D002412:Cations; D005232:Fatty Acids, Volatile; D008372:Manure; D017641:Zeolites; D008697:Methane