19-08-2014, 11:37 AM
The present work was undertaken to further study a white rot fungus designated as WR-1, an indigenous isolate, reported by Revankar and Lele, 2006. This isolate was found to produce high activities of laccase. The objectives of this project are as follows: I)Comparison of WR-1 culture with some more standard laccase producing cultures II)Immobilization of laccase enzyme produced from WR-1 III) To study alternate downstream processing protocols for laccase.
Due to intellectual property rights, indigenous isolates having good enzymatic system are of greater importance for technology development. White rot fungi are eukaryotic microorganisms that degrade lignin by its unique ligninolytic enzymatic machinery including lignin peroxidases, manganese peroxidases and laccases. Laccases (benzenediol: oxygen oxidoreductase, EC 1.10.3.2) are multi-copper oxidases widely distributed among plants, insects, and fungi. These enzymes catalyze the one electron oxidation of a wide variety of organic and inorganic substrates. These enzymes are widely used for waste water treatment especially in textile industries.
The present work was undertaken to further study a white rot fungus designated as WR-1, an indigenous isolate, reported by Revankar and Lele, 2006. This isolate was found to produce high activities of laccase. The objectives of this project are as follows: I)Comparison of WR-1 culture with some more standard laccase producing cultures II)Immobilization of laccase enzyme produced from WR-1 III) To study alternate downstream processing protocols for laccase.
Various laccase producing strains were procured and their laccase production is compared with the isolate. The isolate was found to produce higher amounts of laccase (302 U/ml) than many other standard cultures. Fermentation in batch mode was also carried out in a lab made 4 L indigenous sparged fermentor with 2 L working volume. Ammonium sulphate precipitation of the crude enzyme is also done. The crude enzyme was immobilized by entrapment in copper alginate beads. A bead size of 2mm, copper sulphate concentration of 1.5 M, sodium alginate concentration of 2.5%(w/v), reaction pH of 5.0 were found to be optimum. Kinetic constants, Km and Vmax of the immobilized enzyme were estimated and the thermal stability, pH stability and operational stability of the immobilized enzyme were also studied.