Characterization of an extracellular laccase of Leptosphaerulina chartarum.
Laccase-producing fungi were isolated from air, using selective media with a chromogenic substrate to indicate enzyme activity. The best laccase producer strain proved to be a Leptosphaerulina chartarum isolate. Laccase production was investigated in the presence of various inducers in different cultivation conditions. The extracellular laccase was purified for further investigations. SDS-PAGE showed that this laccase is a monomeric protein of 38 kDa molecular weight. The enzyme is active in the pH-range of 3.5-6, with an optimum at pH 3.8. It is active in the 10-60 °C temperature range, with an optimum at 40 °C. After 20 min incubation at temperatures above 70 °C the enzyme lost its activity. Degradation of seven aniline and phenol compounds (2,4-dichlorophenol; 2-methyl-4-chlorophenol; 3-chloroaniline; 4-chloroaniline; 2,6-dimethylaniline; 3,4-dichloroaniline and 3-chloro-4-methylaniline) was investigated, with or without guaiacol (2-methoxyphenol) as mediator molecule. Addition of a mediator to the system significantly increased the degradation levels. These results confirmed that the isolated laccase is able to convert these harmful xenobiotics at in vitro conditions.
Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Közép fasor 52, Szeged, 6726, Hungary, sajben@gmail.com.
Enikő
E
Sajben-Nagy
László
L
Manczinger
Biljana
B
Škrbić
Jelena
J
Živančev
Igor
I
Antić
Judit
J
Krisch
Csaba
C
Vágvölgyi
D000391:Air Microbiology; D000814:Aniline Compounds / Q000378:metabolism; D001203:Ascomycota / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D001711:Biotransformation; D003470:Culture Media / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D010636:Phenols / Q000378:metabolism; D013696:Temperature
D000814:Aniline Compounds; D003470:Culture Media; D010636:Phenols; D042845:Laccase; C023650:aniline