PRODUCTION OF LACCASE BY BOTRYTIS-CINEREA AND FERMENTATION STUDIES WITH STRAIN F226

After induction, seven strains of Botrytis cinerea released into the c ulture broth considerable amounts of laccase in a brief production tim e. The set-up of a suitable production process was studied with a sele cted strain in a 10-L fermenter. The optimum fermentation conditions w ere a 3% inoculum with a high degree of sporulation, a simple medium c ontaining 20 g L(-1) of glucose and 2 g L(-1) of yeast extract at pH 3 .5, 2 g L(-1) gallic acid as inducer, added after 2 days of growth, an agitation speed of 300 rpm, an aeration rate of 1.2 vvm and a tempera ture of 24 degrees C. By optimizing the culture conditions, the enzyme activity reached 28 U ml(-1) in 5 days with a specific activity of 56 0 U mg(-1) protein. The best procedure to obtain a suitable crude enzy me preparation was concentration of the supernatant medium to 10% of t he initial volume by ultrafiltration, followed by a fractional precipi tation with ethanol. The optimum pH and temperature for laccase activi ty were 5.5 and 40 degrees C, respectively, with syringaldazine as the substrate.