title: Effects of inoculum type and bulk dissolved oxygen concentration on achieving partial nitrification by entrapped-cell-based reactors.
abstract: An entrapment of nitrifiers into gel matrix is employed as a tool to fulfill partial nitrification under non-limiting dissolved oxygen (DO) concentrations in bulk solutions. This study aims to clarify which of these two attributes, inoculum type and DO concentration in bulk solutions, is the decisive factor for partial nitrification in an entrapped-cell based system. Four polyvinyl alcohol entrapped inocula were prepared to have different proportions of nitrite-oxidizing bacteria (NOB) and nitrite-oxidizing activity. At a DO concentration of 3 mg l(-1), the number of active NOB cells in an inoculum was the decisive factor for partial nitrification enhancement. However, when the DO concentration was reduced to 2 mg l(-1), all entrapped cell inocula showed similar degrees of partial nitrification. The results suggested that with the lower bulk DO concentration, the preparation of entrapped cell inocula is not useful as the DO level becomes the decisive factor for achieving partial nitrification.
authors.affiliation: International Postgraduate Programs in Environmental Management, Graduate School, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand; Faculty of Environmental Management, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand. Electronic address: chaiwat.r@psu.ac.th.
authors.forename: Chaiwat
authors.initials: C
authors.lastname: Rongsayamanont
authors.affiliation: Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand; Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand. Electronic address: tawan.l@chula.ac.th.
authors.forename: Tawan
authors.initials: T
authors.lastname: Limpiyakorn
authors.affiliation: Department of Civil and Environmental Engineering, College of Engineering, North Dakota State University, Fargo, ND 58108, USA. Electronic address: eakalak.khan@ndsu.edu.
authors.forename: Eakalak
authors.initials: E
authors.lastname: Khan
mesh_terms: D000641:Ammonia / Q000378:metabolism; D001105:Archaea / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D001419:Bacteria / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D018914:Cells, Immobilized / Q000187:drug effects / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D058465:Nitrification / Q000187:drug effects*; D010084:Oxidation-Reduction / Q000187:drug effects; D010100:Oxygen / Q000494:pharmacology*; D012995:Solubility
chemical_list: D000641:Ammonia; D010100:Oxygen
keywords: Entrapped cell; Fluorescence in situ hybridization; Inoculum; Oxygen; Partial nitrification