Showing papers by "Andrzej Leonowicz published in 2007"

Culture conditions of psychrotrophic fungus, Penicillium chrysogenum and its lipase characteristics

Abstract: Among 97 fungal strains from the soil collected from the high mountain areas in the Jeju Island, Korea, Penicillium chrysogenum 9 was found to be the best lipase producer. Its lipase productivity reached 42 U/ml in the culture medium. Factors affecting lipase production by Penicillium chrysogenum 9 were studied using fermentation media of different chemical compositions. Under optimal conditions we noted a 1.6-fold increase of lipase activity. The maximum lipase activity was 68 U/ml of culture medium on the 5th day of incubation at pH 6.0 and 20 ˚C; therefore, Penicillium chrysogenum 9 was classified as a psy- chrotrophic microorganism. The enzyme from Penicillium chrysogenum 9 showed a maximum activity at 30 ˚C and pH 5.0 for synthetic substrates (triacylglycerols) or at pH 7.0 for natural substrates (oils).

Effect of Fungal Laccase and New Mediators, Acetovanillone and Acetosyringone, on Decolourization of Dyes

Abstract: Several wood rotting fungi decolourized Remazol brilliant blue R (RBBR) and carminic acid (CA). Parallel activity of laccase in these fungi was studied. The addition of acetovanillone (AV) or ace- tosyringone (AS) intensified these processes: decolourization was more extensive than in the experiment omitting these compounds. At the presence of AS the decourization was more extensive than AV. However the level of destaining was relatively low in comparison to laccase activity on syringaldazine. The highly purified constitutive form of Cerrena unicolor and inducible form of Trametes versicolor laccases also decolourized both dyes. The fungus, Lentinus lepideus, which has no laccase activity did not decolourize at all. Nitrogen starvation induced the laccase and decolourization activity in both organisms, irrespective of nitrogen availability. This fact indicates laccase not solely responsible for decolourization, and probably decolourization of dyes involves more than one mechanism.

Production of Mn-Dependent Peroxidase from Bjerkandera fumosa and Its Enzyme Characterization

Abstract: Manganese dependent peroxidase (MnP) is the most ubiquitous enzyme produced by white-rot fungi, MnP is known to be involved in lignin degradation, biobleaching and oxidation of hazardous organopollutants. Bjerkandera fumosa is a nitrogen-unregulated white-rot fungus, which produces high amounts of MnP in the excess of N-nutrients due to increased biomass yield. The objective of this study was to optimize the MnP production in N-sufficient cultures by varying different physiological factors such as Mn concentration, culture pH, and incubation temperature. The growth of fungus was optimal in pH 4.5 at , -unregulated white-rot fungus produces high amounts of MnP in the excess N-nutrients. The fungus produced the highest level of MnP (up to ) with asparagine and as N source at 1.5 mM concentration, pH value of 4.5 at . Purification of MnP revealed the existence of two isoforms: MnPl and MnP2. The molecular masses of the purified MnPl and MnP2 were in the same range of 42~45 kDa. These isoforms of B. fumosa strictly require Mn to oxidize phenolic substrates. Concerned to kinetic constants of B. fumosa MnPs, B. fumosa has similar Km value and Vmax compared to the other white-rot fungi.