title: Effect of freeze-thaw process on physical properties, microbial activities and population structures of anaerobic sludge.
abstract: Effects of the freeze-thaw process on physical properties, cell viability, microbial activities and population structures of anaerobic sludge were investigated. It was found that the sludge volume index was greatly reduced from 16.4 mL/g in the original sludge to 4.0 mL/g in the solid fraction of the frozen-thawed sludge. Even though the freeze-thaw process decreased cell viability in the solid fraction of the frozen-thawed sludge, microbial activity tests showed that the freeze-thaw process enhanced acidogenic activity approximately 20%. The enhanced acidogenic activity of the solid fraction was in good agreement with the enrichment of Clostridiaceae, Porphyromonadaceae and Propionibacteriaceae found in the solid fraction. The relative abundances of Proteobacteria families Oxalobacteraceae, Moraxellaceae, and Pseudomonadaceae were found to be highest in the liquid fraction where they form a substantial proportion of the bacterial community (a total of 59%).
authors.affiliation: The Research and Technology Center for Renewable Products and Energy, King Mongkut's University of Technology North Bangkok, Bangsue, Bangkok 10800, Thailand; Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology North Bangkok, Bangsue, Bangkok 10800, Thailand. Electronic address: cpk@kmutnb.ac.th.
authors.forename: Chantaraporn
authors.initials: C
authors.lastname: Phalakornkule
authors.affiliation: Thailand Institute of Nuclear Technology, Nakhon Nayok 26120, Thailand.
authors.forename: Sasikarn
authors.initials: S
authors.lastname: Nuchdang
authors.affiliation: The Research and Technology Center for Renewable Products and Energy, King Mongkut's University of Technology North Bangkok, Bangsue, Bangkok 10800, Thailand.
authors.forename: Maneerat
authors.initials: M
authors.lastname: Khemkhao
authors.affiliation: Enzyme Technology Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Khlong Luang, Pathum Thani 12120, Thailand.
authors.forename: Wuttichai
authors.initials: W
authors.lastname: Mhuantong
authors.affiliation: Enzyme Technology Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Khlong Luang, Pathum Thani 12120, Thailand.
authors.forename: Sarunyou
authors.initials: S
authors.lastname: Wongwilaiwalin
authors.affiliation: Genome Institute, National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Khlong Luang, Pathum Thani 12120, Thailand.
authors.forename: Sithichoke
authors.initials: S
authors.lastname: Tangphatsornruang
authors.affiliation: Enzyme Technology Laboratory, Bioresources Technology Unit, National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Khlong Luang, Pathum Thani 12120, Thailand.
authors.forename: Verawat
authors.initials: V
authors.lastname: Champreda
authors.affiliation: The Research and Technology Center for Renewable Products and Energy, King Mongkut's University of Technology North Bangkok, Bangsue, Bangkok 10800, Thailand; Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology North Bangkok, Bangsue, Bangkok 10800, Thailand.
authors.forename: Jiraprat
authors.initials: J
authors.lastname: Kitsuwan
authors.affiliation: Department of Agro-Industrial Technology, Faculty of Applied Science, King Mongkut's University of Technology North Bangkok, Bangsue, Bangkok 10800, Thailand.
authors.forename: Savitri
authors.initials: S
authors.lastname: Vatanyoopaisarn
mesh_terms: D000143:Acids / Q000378:metabolism; D000693:Anaerobiosis; D005615:Freezing; D006863:Hydrogen-Ion Concentration; D050296:Microbial Viability; D020560:Proteobacteria / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*
chemical_list: D000143:Acids; D012336:RNA, Ribosomal, 16S; D012722:Sewage
keywords: Anaerobic sludge; Biohydrogen; Freeze–thaw; Microbial activity; Tagged 16S rRNA gene pyrosequencing