Production of two novel laccase isoforms by a thermotolerant strain of Pycnoporus sanguineus isolated from an oil-polluted tropical habitat.
A thermotolerant and halotolerant strain of Pycnoporus sanguineus was isolated from an oil-polluted site in a tropical area located in Veracruz, Mexico. This strain was able to grow at 47 degrees C and in culture medium containing 500 mM NaCl. The strain was also tolerant to the presence of 30,000 ppm of crude Maya oil. A 68-kDa protein purified from submerged cultures exhibited laccase activity towards 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), guaiacol, syringaldazine, and o-dianisidine, for which it presented the highest affinity (Km = 43 microM). Two-dimensional gel electrophoresis analysis showed that, unusual for laccases, the enzyme has two active isoforms, with isoelectric points of 7.00 and 7.08. The purified enzyme showed high thermostability, retaining 40% of its original activity after 3 h at 60 degrees C. This property seems to correlate with a long "shelf-life," given that at 40 degrees C enzyme activity was only gradually lost over a 5-day period incubation. Both the fungus and its laccase are likely to have high potential for biotechnological applications.
Dantán-González
Edgar
E
Biotechnology Research Center, Autonomous University of the State of Morelos, Cuernavaca, Mexico.
Vite-Vallejo
Odón
O
Martínez-Anaya
Claudia
C
Méndez-Sánchez
Mónica
M
González
María C
MC
Palomares
Laura A
LA
Folch-Mallol
Jorge
J
D017753:Ecosystem; D004787:Environmental Pollution; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D006358:Hot Temperature; D007527:Isoenzymes / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D042845:Laccase / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D008800:Mexico; D010578:Petroleum; D024301:Plant Bark / Q000382:microbiology*; D011124:Polyporaceae / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology; D013379:Substrate Specificity; D014329:Tropical Climate
D005656:Fungal Proteins; D007527:Isoenzymes; D010578:Petroleum; D012965:Sodium Chloride; D042845:Laccase