Biological Degradation of Anthroquinone and Azo Dyes by a Novel Laccase from Lentinus sp.

详细信息    查看全文

• 作者：Chih-An Hsu ; Tuan-Nan Wen ; Yu-Chang Su ; Zhi-Bing Jiang ; Chin-Wen Chen ; Lie-Fen Shyur
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：May 1, 2012
• 年：2012
• 卷：46
• 期：9
• 页码：5109-5117
• 全文大小：570K
• 年卷期：v.46,no.9(May 1, 2012)
• ISSN：1520-5851

文摘

This study identifies a new fungal strain, Lentinus sp., that can produce extracellular forms of laccases with an activity of approximately 58鈥?00 U/L. A purified laccase (designated lcc3) was identified by LC-ESI MS/MS as an N-linkage glycosylated protein. The isolated lcc3 cDNA is composed of 1563 bp encoding for a polypeptide of 521 amino acid residues with 4 putative Cu binding regions. Kinetic analyses revealed that the specific activity, k_cat, K_m, and k_cat/K_m of lcc3 at pH 2.5 and 70 掳C with 2,2鈥?azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) used as a substrate was 2047 U mg^鈥?, 2017 s^鈥?, 8.4 渭M, and 240 s^鈥? 渭M^鈥?, respectively. Lcc3 is stable at pH 6.0鈥?0.0 and has a midpoint temperature (T_m) of 77.1 掳C. We observed 97% decolorization efficiency on Acid Blue 80, 88% on RBBR, and 61% on Acid Red 37 by lcc3. Structural modeling analysis showed that five, four, and three hydrogen bonds can be formed between Acid Blue 80 and Arg¹⁷⁸, Arg¹⁸², or Asn³⁵⁸; between RBBR and His¹³², Ser¹³⁴, or Asp⁴⁸²; and between Acid Red 37 and Arg¹⁷⁸, respectively. Notably, Lentinus lcc3 efficiently reversed the toxicity of anthraquinone and azo dyes on rice seed germination and decolorized industrial textile effluent, suggesting the enzyme may be valuable for bioremediation.