title: Bacillus sp. mutant for improved biodegradation of Congo red: random mutagenesis approach.
abstract: This study presents the improved biodegradation of Congo red, a toxic azo dye, using mutant Bacillus sp. obtained by random mutagenesis of wild Bacillus sp. using UV and ethidium bromide. The mutants obtained were screened based on their decolorization performance and best mutants were selected for further studies. Better decolorization was observed in the initial Congo red concentration range 100-1000 mg/l for wild species whereas mutant strain was found to offer better decolorization up to 3000 mg/l. Mutant strain offered 12-30% reduction in time required for the complete decolorization by wild strain. The optimum pH and temperature were found to be 7.0 and 37 degrees C, respectively. Two efficient strains such as Bacillus sp. ACT 1 and Bacillus sp. ACT 2 were isolated from the various mutants obtained. Bacillus sp. ACT 2 showed improved enzymatic production and Bacillus sp. ACT 1 showed improved growth compared to wild strain. The enzyme responsible for the degradation was found to be azoreductase by SDS-PAGE and about 53% increased production of enzyme was achieved with mutant species. The experimental data were modeled using growth and substrate inhibition models.
authors.affiliation: Department of Chemical Engineering, Alagappa College of Technology Campus, Anna University Chennai, Chennai 600 025, India.
authors.forename: Kannappan Panchamoorthy
authors.initials: KP
authors.lastname: Gopinath
authors.forename: Shreela
authors.initials: S
authors.lastname: Murugesan
authors.forename: Joanna
authors.initials: J
authors.lastname: Abraham
authors.forename: Karuppan
authors.initials: K
authors.lastname: Muthukumar
mesh_terms: D001407:Bacillus / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000528:radiation effects; D001673:Biodegradation, Environmental / Q000187:drug effects / Q000528:radiation effects; D003116:Color; D003224:Congo Red / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D004591:Electrophoresis, Polyacrylamide Gel; D052918:Environmental Restoration and Remediation / Q000379:methods*; D004996:Ethidium; D006863:Hydrogen-Ion Concentration / Q000187:drug effects / Q000528:radiation effects; D007700:Kinetics; D019216:Metals, Heavy / Q000494:pharmacology; D008956:Models, Chemical; D016296:Mutagenesis / Q000528:radiation effects; D009154:Mutation / Q000235:genetics*; D009247:NADH, NADPH Oxidoreductases / Q000302:isolation & purification; D009601:Nitroreductases; D010100:Oxygen / Q000032:analysis; D012492:Salts / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D014466:Ultraviolet Rays
chemical_list: D019216:Metals, Heavy; D012492:Salts; D003224:Congo Red; D009247:NADH, NADPH Oxidoreductases; D009601:Nitroreductases; C021106:azoreductase; D004996:Ethidium; D010100:Oxygen