Decolorization of Textile Dyes by anImmobilized Laccase Produced from Local Isolate of Pseudomonas aeruginosa SR3 Using Packed Bed-Reactor

 
Prepared by:
Teacher Sahar Irhaim Hussein/ Department of biotechnologies,  Faculty of science, University of Baghdad
Dr. Nazim Hassan Haider/ Department of biotechnologies,  Faculty of science, University of Baghdad
Dr. Ghazi Muneim Aziz/ Department of biotechnologies,  Faculty of science, University of Baghdad
 
Abstract
 

The present study was aimed to production laccase enzyme from the local isolate of Pseudomonas aeruginosa SR3 and using immobilized laccase for removing the different textile dyes by batch and continuous system.Laccase was produced by local isolate of Pseudomonas aeruginosa SR3 using lab scale fermenter after 24 hr of fermentation, the specific activity was reached to 6214 U/mg proteinwhen xylene concentration was nearly depleted from the medium in the fermenter . Immobilization of enzyme was conducted in two methods, entrapment by calcium alginate and agar-agar with maximum immobilization efficiency 49% and 32%, respectively and covalent method by chitosan and gelatin with maximum immobilization efficiency 63% and 50% respectively. The decolorization capability of immobilized laccase on chitosan loaded with black dye at concentration of (30 mg/l) in packed bed-reactor with pH 5.0 at 30oC operated as a batch culture system for 3 hrs. Decolorization rate was increased through the incubation time and stabilized approximately after 2 hr with removal efficiency 97.3% of dye. Decolorization of black textile dye was performed also by operation of packed bed bioreactor continuously at different flow rates (15, 30 and 45) ml/hr and HRT (7.9, 3.9 and 2.6) hr. respectively. The black textile dye was loaded over the chitosan immobilized laccase with total working volume of 118 ml at concentration of (30 mg/l) in pH 5.0 at 30oC. Decolorization efficiency of black textile dye with immobilized laccase in a bioreactor increased at flow rate 15 ml/ hr., and reached to 71% after 2.5 hr. While the increase in flow rate to 30 and 45 ml/ hr. resulted in dropping of decolorization rate of dye to 60 and 47% respectively after period of time.