Optimization of some variables that affect the synthesis of laccase by Pleurotus ostreatus

The influence of initial pH, concentration of yeast extract, inducer, type of enzyme releaser and buffer system on the composition of a medium for lac case production by Pleurotus ostreatus DM-1513 was investigated. A 2(5) ful l factorial experimental design was initially employed to evaluate the effe cts of these variables on the enzyme synthesis. Data analysis showed that l ow pH and high yeast extract concentration values, as well as the absence o f both an inducer and a buffer system, had positive effects on the secreted enzyme levels, whereas the type of enzyme releaser did not have a signific ant effect. The highest levels of laccase activity (489-540 U/l) were obtai ned in optimization experiments using media with initial pH between 6.0 and 6.5 and yeast extract concentrations of 0-0.25%.