by Chan Cho-Yin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 161-173). / Text in English; abstracts in English and Chinese. / by Chan Cho-Yin. / Acknowledgements --- p.i / Abstracts --- p.ii / Table of Contents --- p.vi / List of Figures --- p.xii / List of Plates --- p.xv / List of Tables --- p.xvi / Abbreviations --- p.xix / Equations --- p.1 / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Atrazine --- p.1 / Chapter 1.1.1 --- Characteristics of atrazine --- p.1 / Chapter 1.1.2 --- Use of atrazine --- p.7 / Chapter 1.1.3 --- Inhibitory mechanisms --- p.7 / Chapter 1.1.4 --- Global annual consumption --- p.7 / Chapter 1.1.5 --- Environmental fate --- p.8 / Chapter 1.1.5.1 --- Major intermediates --- p.10 / Chapter 1.1.6 --- Ecotoxicity --- p.10 / Chapter 1.1.6.1 --- Toxicity towards microorganisms --- p.10 / Chapter 1.1.6.2 --- Toxicity towards invertebrates --- p.12 / Chapter 1.1.6.3 --- Toxicity towards vertebrates --- p.15 / Chapter 1.1.7 --- Environmental regulations --- p.16 / Chapter 1.2 --- Treatments of atrazine --- p.16 / Chapter 1.2.1 --- Physical treatments --- p.16 / Chapter 1.2.2 --- Chemical treatments --- p.18 / Chapter 1.2.3 --- Advanced Oxidation Processes (AOPs) --- p.19 / Chapter 1.2.4 --- Photocatalytic Oxidation (PCO) --- p.21 / Chapter 1.2.4.1 --- Cyanuric acid --- p.26 / Chapter 1.2.5 --- Biological treatments --- p.33 / Chapter 1.2.6 --- Integration of treatment methods --- p.36 / Chapter 2 --- Objectives --- p.38 / Chapter 3 --- Materials and methods --- p.39 / Chapter 3.1 --- Photocatalytic oxidation (PCO) reaction --- p.39 / Chapter 3.1.1 --- Chemical reagents --- p.39 / Chapter 3.1.2 --- Photocatalytic reactor --- p.39 / Chapter 3.1.3 --- Determination of atrazine --- p.43 / Chapter 3.1.4 --- Optimization of PCO reactions --- p.43 / Chapter 3.1.4.1 --- Effect of initial hydrogen peroxide concentration --- p.49 / Chapter 3.1.4.2 --- Effect of titanium dioxide concentration --- p.49 / Chapter 3.1.4.3 --- Effect of initial pH --- p.50 / Chapter 3.1.4.4 --- Effect of UV intensities --- p.50 / Chapter 3.1.4.5 --- Internal control of parameters --- p.50 / Chapter 3.1.4.6 --- Combination study of parameters: part one --- p.50 / Chapter 3.1.4.7 --- Combination study of parameters: part two --- p.50 / Chapter 3.1.5 --- Detection methods of atrazine degradation intermediates/products --- p.51 / Chapter 3.1.5.1 --- Gas chromatography-mass spectrometry --- p.51 / Chapter 3.1.5.2 --- High performance liquid chromatography --- p.51 / Chapter 3.1.6 --- Investigation of PCO treated solution --- p.54 / Chapter 3.1.6.1 --- Total organic carbon content --- p.54 / Chapter 3.1.6.2 --- Anions content --- p.54 / Chapter 3.1.6.3 --- pH --- p.56 / Chapter 3.1.6.4 --- Hydrogen peroxide content --- p.56 / Chapter 3.1.6.5 --- Toxicity --- p.56 / Chapter 3.1.6.5.1 --- Microtox® test --- p.56 / Chapter 3.1.6.5.2 --- Amphipod survival test --- p.57 / Chapter 3.2 --- Biodegradation reaction --- p.61 / Chapter 3.2.1 --- Chemical reagents --- p.61 / Chapter 3.2.2 --- Sampling --- p.62 / Chapter 3.2.3 --- Enrichment --- p.62 / Chapter 3.2.4 --- Isolation --- p.65 / Chapter 3.2.5 --- Purification --- p.65 / Chapter 3.2.6 --- Identification of bacterial strain --- p.65 / Chapter 3.2.6.1 --- Gram staining --- p.66 / Chapter 3.2.6.2 --- Catalase and oxidase tests --- p.66 / Chapter 3.2.6.3 --- Sherlock Microbial Identification System (MIDI) --- p.66 / Chapter 3.2.6.4 --- Biolog MicroLog´ёØ system (Biolog) --- p.67 / Chapter 3.2.7 --- Determination of cyanuric acid --- p.67 / Chapter 3.2.8 --- Selection of cyanuric acid degrading bacteria --- p.67 / Chapter 3.2.9 --- Optimization of reaction conditions --- p.67 / Chapter 3.2.9.1 --- Starting medium --- p.68 / Chapter 3.2.9.2 --- Effect of temperatures --- p.68 / Chapter 3.2.9.3 --- Effect of initial pH --- p.69 / Chapter 3.2.9.4 --- Effect of agitation rates --- p.69 / Chapter 3.2.9.5 --- Effect of initial cyanuric acid and glucose concentrations --- p.70 / Chapter 3.2.9.6 --- Investigation of biodegraded solution --- p.70 / Chapter 3.2.9.6.1 --- Glucose content --- p.70 / Chapter 3.2.9.6.2 --- Biodegradation metabolite(s) of cyanuric acid --- p.70 / Chapter 3.3 --- Integration of photocatalytic oxidation and biodegradation --- p.71 / Chapter 4 --- Results --- p.72 / Chapter 4.1 --- Photocatalytic oxidation (PCO) reaction --- p.72 / Chapter 4.1.1 --- Determination of atrazine --- p.72 / Chapter 4.1.2 --- Effect of aeration and mixing --- p.72 / Chapter 4.1.3 --- Effect of initial hydrogen peroxide concentrations --- p.72 / Chapter 4.1.4 --- Effect of titanium dioxide concentrations --- p.78 / Chapter 4.1.5 --- Effect of initial pH --- p.78 / Chapter 4.1.6 --- Effect of UV intensities --- p.78 / Chapter 4.1.7 --- Effect of different internal controls --- p.85 / Chapter 4.1.8 --- "Combination of UV intensities, initial hydrogen peroxide and titanium dioxide concentrations" --- p.85 / Chapter 4.1.9 --- "Combination of initial pH, atrazine concentrations and UV intensities" --- p.94 / Chapter 4.1.10 --- Degradation products detected by GC/MS --- p.94 / Chapter 4.1.11 --- Degradation products detected by HPLC --- p.94 / Chapter 4.1.12 --- Total organic carbon removal --- p.104 / Chapter 4.1.13 --- Anions content --- p.104 / Chapter 4.1.14 --- Solution pH --- p.104 / Chapter 4.1.15 --- Hydrogen peroxide content --- p.108 / Chapter 4.1.16 --- Microtox® test --- p.108 / Chapter 4.1.17 --- Amphipod survival test --- p.114 / Chapter 4.2 --- Biodegradation reaction --- p.118 / Chapter 4.2.1 --- Isolation of bacterial colonies --- p.118 / Chapter 4.2.2 --- Identification and characterization of the isolated bacteria --- p.118 / Chapter 4.2.3 --- Selection of cyanuric acid degrading species --- p.118 / Chapter 4.2.4 --- Effect of temperatures --- p.128 / Chapter 4.2.5 --- Effect of initial pH --- p.128 / Chapter 4.2.6 --- Effect of agitation rates --- p.128 / Chapter 4.2.7 --- Effect of cyanuric acid and glucose concentrations --- p.132 / Chapter 4.2.8 --- Glucose content --- p.132 / Chapter 4.2.9 --- Biodegradation metabolites of cyanuric acid --- p.132 / Chapter 4.2.10 --- Proposed pathway of atrazine degradation by biodegradation enhanced by PCO --- p.138 / Chapter 4.3 --- Integration of photocatalytic oxidation and biodegradation --- p.138 / Chapter 5 --- Discussion --- p.141 / Chapter 5.1 --- Photocatalytic oxidation (PCO) reaction --- p.141 / Chapter 5.1.1 --- Determination of atrazine --- p.141 / Chapter 5.1.2 --- Effect of aeration and mixing --- p.141 / Chapter 5.1.3 --- Effect of initial hydrogen peroxide concentrations --- p.141 / Chapter 5.1.4 --- Effect of titanium dioxide concentrations --- p.143 / Chapter 5.1.5 --- Effect of initial pH --- p.143 / Chapter 5.1.6 --- Effect of UV intensities --- p.144 / Chapter 5.1.7 --- Effect of different internal controls --- p.145 / Chapter 5.1.8 --- "Combination of UV intensities, initial hydrogen peroxide and titanium dioxide concentrations" --- p.145 / Chapter 5.1.9 --- "Combination of initial pH, atrazine concentrations and UV intensities" --- p.146 / Chapter 5.1.10 --- Degradation products detected by GC/MS --- p.146 / Chapter 5.1.11 --- Degradation products detected by HPLC --- p.147 / Chapter 5.1.12 --- Total organic carbon removal --- p.147 / Chapter 5.1.13 --- Anions content --- p.148 / Chapter 5.1.14 --- Solution pH --- p.149 / Chapter 5.1.15 --- Hydrogen peroxide content --- p.149 / Chapter 5.1.16 --- Microtox® test --- p.149 / Chapter 5.1.17 --- Amphipod survival test --- p.150 / Chapter 5.2 --- Biodegradation reaction --- p.151 / Chapter 5.2.1 --- Isolation of bacterial colonies --- p.151 / Chapter 5.2.2 --- Identification and characterization of the isolated bacteria --- p.151 / Chapter 5.2.3 --- Selection of cyanuric acid degrading species --- p.152 / Chapter 5.2.4 --- Effect of temperatures --- p.152 / Chapter 5.2.5 --- Effect of initial pH --- p.153 / Chapter 5.2.6 --- Effect of agitation rates --- p.153 / Chapter 5.2.7 --- Effect of cyanuric acid and glucose concentrations --- p.154 / Chapter 5.2.8 --- Glucose content --- p.154 / Chapter 5.2.9 --- Biodegradation metabolites of cyanuric acid --- p.155 / Chapter 5.2.10 --- Proposed degradation pathway of atrazine by biodegradation enhanced by PCO --- p.155 / Chapter 5.3 --- Integration of photocatalytic oxidation and biodegradation --- p.155 / Chapter 6 --- Conclusions --- p.159 / Chapter 7 --- References --- p.161 / Appendix1 --- p.174 / Appendix2 --- p.175

The impact of different atrazine concentration on a chitinolytic actinomycete and the biodegradation of atrazine by this microbe was examined.Isolates were grown in pure culture in Chitin Mineral Salts Broth with and without addition of atrazine for a two month incubation at room temperature on a rotary shaker. Visual observations, analysis by High Performance Liquid Chromatography (HPLC) and radioisotope methodology were used to determine this impact on chitinolytic activity. Analysis by HPLC and Gas Chromatography with Electron Capture Detector (GC with ECD) were used to determine the breakdown of atrazine.No atrazine derivatives were determined by HPLC and GC analysis. Only the 0.1 ppm atrazine concentration with the actinomycete culture demonstrated tolerance to the atrazine and showed chitinolytic activity in the radioactive assay and chitin derivatives by HPLC. SEM and TEM work determined that the actinomycete was actually a Streptomyces sp. / Department of Biology

A facultative anaerobic bacterium that rapidly degrades cyanuric acid (CA) was isolated from sediment of a stream that received industrial waste water effluent. CA decomposition was measured throughout the growth cycle by using a High Performance Liquid Chromatography assay while also measuring the concomitant production of ammonia. This bacterium used CA or cysteine as a major, if not sole, carbon and energy source under anaerobic, but not aerobic conditions in a defined medium. The cell yield was greatly enhanced by the simultaneous presence of cysteine and CA in the medium. Cysteine was preferentially used rather than CA early in the growth cycle, but all the CA was used without an apparent lag after the cysteine was metabolized. Atrazine was also degraded by this bacterium under anaerobic conditions in a defined medium. / Master of Science