Optimization of laccase production by Pycnoporus sanguineus in submerged liquid culture

Abstract

The white-rot fungus Pycnoporus sanguineus produces laccase under a range of C/N ratios in submerged liquid culture. Enzyme production was increased 50 fold in the presence of 20 μM xylidine to a maximum of 1368 U L-1 in a high carbon low nitrogen medium. Slight repression of enzyme production was observed in high nitrogen culture medium. Other potential inducers were less effective (Tween 80, wood fibres) and reduced the stimulation observed by xylidine alone when included in the same culture medium. Veratryl alcohol failed to stimulate laccase production. Activity of the enzyme activity in crude culture nitrate was stable at temperatures of 35 C and below with a pH optimum of 3.0. The laccase of P. sanguineus was identified as a ca 65 kDa protein produced as multiple isoforms.