A High Redox Potential Laccase from Pycnoporus sanguineus RP15: Potential Application for Dye Decolorization

• Published in: International journal of molecular sciences 2016-05, Vol.17 (5), p.672-672
• Main Authors: Zimbardi, Ana L R L, Camargo, Priscila F, Carli, Sibeli, Aquino Neto, Sidney, Meleiro, Luana P, Rosa, Jose C, De Andrade, Adalgisa R, Jorge, João A, Furriel, Rosa P M
• Format: Article
• Language: English
• Subjects: Benzothiazoles - chemistry; bromophenol blue; characterization; Coloring Agents - chemistry; decolorization; Fermentation; Fungal Proteins - metabolism; laccase; Laccase - metabolism; Oxidation-Reduction; purification; Pycnoporus - enzymology; Pycnoporus - growth & development; Pycnoporus sanguineus; Reactive blue 4; remazol brilliant blue R; response surface methodology; solid state fermentation; Sulfonic Acids - chemistry; Triticum aestivum
• ISSN: 1422-0067; 1422-0067
• DOI: 10.3390/ijms17050672

Laccase production by Pycnoporus sanguineus RP15 grown in wheat bran and corncob under solid-state fermentation was optimized by response surface methodology using a Central Composite Rotational Design. A laccase (Lacps1) was purified and characterized and the potential of the pure Lacps1 and the crude culture extract for synthetic dye decolorization was evaluated. At optimal conditions (eight days, 26 °C, 18% (w/w) milled corncob, 0.8% (w/w) NH₄Cl and 50 mmol·L(-1) CuSO₄, initial moisture 4.1 mL·g(-1)), the laccase activity reached 138.6 ± 13.2 U·g(-1). Lacps1 was a monomeric glycoprotein (67 kDa, 24% carbohydrate). Optimum pH and temperature for the oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) were 4.4 and 74.4 °C, respectively. Lacps1 was stable at pH 3.0-8.0, and after two hours at 55-60 °C, presenting high redox potential (0.747 V vs. NHE). ABTS was oxidized with an apparent affinity constant of 147.0 ± 6.4 μmol·L(-1), maximum velocity of 413.4 ± 21.2 U·mg(-1) and catalytic efficiency of 3140.1 ± 149.6 L·mmol(-1)·s(-1). The maximum decolorization percentages of bromophenol blue (BPB), remazol brilliant blue R and reactive blue 4 (RB4), at 25 or 40 °C without redox mediators, reached 90%, 80% and 60%, respectively, using either pure Lacps1 or the crude extract. This is the first study of the decolorization of BPB and RB4 by a P. sanguineus laccase. The data suggested good potential for treatment of industrial dye-containing effluents.