ABSTRACT
Abstract Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30 °C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability.
Subject(s)
Bacteria/chemistry , Microbiological Techniques/methods , Ammonia/metabolism , Oxidation-Reduction , Polyvinyl Alcohol/chemistry , Temperature , Bacteria/metabolism , Microbiological Techniques/economics , Microbiological Techniques/instrumentation , Cells, Immobilized/metabolism , Cells, Immobilized/chemistry , Glucuronic Acid/chemistry , Alginates/chemistry , Hexuronic Acids/chemistry , Hydrogen-Ion ConcentrationABSTRACT
Degree of hydrolysis has a key role in the properties of polyvinyl alcohol and its copolymers. Degree of hydrolysis affects swelling, thermal behaviour as well as release of incorporated drugs. However, these properties are also affected by the composition of the copolymers and degree of crosslinking. Furthermore degree of swelling and drug release decreased by increasing the crystallinity in the copolymer