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

Abstract

The in¯uence of initial pH, concentration of yeast extract, inducer, type of enzyme releaser and buffer system on the composition of a medium for laccase production by Pleurotus ostreatus DM-1513 was investigated. A 2 5 full factorial experimental design was initially employed to evaluate the effects of these variables on the enzyme synthesis. Data analysis showed that low pH and high yeast extract concentration values, as well as the absence of 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 signi®cant effect. The highest levels of laccase activity (489±540 U/l) were obtained in optimization experiments using media with initial pH between 6.0 and 6.5 and yeast extract concentrations of 0±0.25%.

Production, purification and partial characterisation of a novel laccase from the white-rot fungus Panus tigrinus CBS 577.79

“…With regard to nitrogen concentration, a condition of sufficiency was adopted since it was previously observed that laccase production levels by P. tigrinus CBS 577.79 were very low or absent under nitrogen limitation (Quaratino 2005;Quaratino et al 2006). In this respect, these findings are in agreement with earlier studies reporting that culture conditions in which nutrients, including carbon, sulphur and, above all, nitrogen, were not limiting resulted in markedly improved laccase production (D'Souza et al 1999;Medeiros et al 1999;Galhaup et al 2002). However, when the laccase activity peak was reached, the nitrogen source was found to be only partially depleted from the medium (present study).…”

Changes in lignocellulolytic enzyme activites in six Pleurotus spp. strains cultivated on coffee pulp in confrontation with Trichoderma spp.

“…Oxidase activity agreed with that reported by Mata & Savoie (1998a) for L. edodes, by Savoie (1998) for A. bisporus, and by Vela´zquez-Ceden˜o et al (2002) for P. ostreatus and P. pulmonarius. According to Buswell et al (1996), changes in enzymatic activity and phenol concentration observed during vegetative development suggest that Mn peroxidase might be involved in the depolymerization of substrates, while laccase might be associated with the detoxification of soluble phenolic compounds, as well as the degradation of lignin (Medeiros et al 1999;Hublik & Schinner 2000;Lucas et al 2001). Laccase activity and the degradation of phenols were negatively correlated (r ¼ )0.61), except in the case of the P. djamor strains (IE 121, IE 218) in which activity levels were low (r ¼ )0.41) but phenols were nevertheless degraded.…”

Enhanced production of laccase in repeated-batch cultures of Funalia trogii and Trametes versicolor

“…It was reported that pH 5.2 was the best value for laccase production of T. versicolor [25]. Similarly, Medeiros et al [26] reported that low pH had positive effect on laccase production activity of P. ostreatus.…”