Study of laccase production by Pleurotus ostreatus in a 5 l bioreactor and application of the enzyme to determine the antioxidant concentration of human plasma

摘要

To achieve high laccase production from Pleurotus ostreatus in a bench top bioreactor and to utilize the enzyme for determination of the total antioxidant concentration (TAC) of human plasma. Laccase production by P. ostreatus studied in a benchtop bioreactor was as high as, 874p"0 U mlp# in presence of copper sulfate. The enzyme was used to replace metmyoglobin and hydrogen peroxide for the estimation of TAC in human plasma. The trolox equivalent antioxidant concentrations determined by the laccase-based method and metmyoglobin method ranged from 1p"63 pl 0p"011 to 1p"80 pl 0p"006 mmol lp# and from 1p"41 pl 0p"004 to 1p"51 pl 0p"008 mmol lp# plasma, respectively. Pleurotus ostreatus produced high amount of extracellular laccase in a benchtop bioreactor. The enzyme can be used to assay TAC of blood plasma without the interference encountered with the hydrogen peroxide and metmyoglobin mediated assay method. Laccase production by P. ostreatus obtained in this study was the highest among all reported laccase producing white-rot fungi. Moreover, an accurate laccase-based assay method was developed for detection of TAC in human plasma.