Properties of the newly isolated extracellular thermo-alkali-stable laccase from thermophilic actinomycetes, Thermobifida fusca and its application in dye intermediates oxidation

• Published in: AMB Express 2013-08, Vol.3 (1), p.49-49, Article 49
• Main Authors: Chen, Cheng-Yu, Huang, Yu-Chun, Wei, Chien-Mei, Meng, Menghsiao, Liu, Wen-Hsiung, Yang, Chao-Hsun
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Biotechnology; Life Sciences; Microbial Genetics and Genomics; Microbiology; Original; Original Article
• ISSN: 2191-0855; 2191-0855
• DOI: 10.1186/2191-0855-3-49

Laccases are diphenol oxidases that have numerous applications to biotechnological processes. In this study, the laccase was produced from the thermophilic actinomycetes, Thermobifida fusca BCRC 19214. After 36 h of fermentation in a 5-liter fermentor, the culture broth accumulated 4.96 U/ml laccase activity. The laccase was purified 4.64-fold as measured by specific activity from crude culture filtrate by ultrafiltration concentration, Q-Sepharose FF and Sephacryl™ S-200 column chromatography. The overall yield of the purified enzyme was 7.49%. The molecular mass of purified enzyme as estimated by SDS-PAGE and by gel filtration on Sephacryl™ S-200 was found to be 73.3 kDa and 24.7 kDa, respectively, indicating that the laccase from T. fusca BCRC 19214 is a trimer. The internal amino acid sequences of the purified laccase, as determined by LC-MS/MS, had high homology with a superoxide dismutase from T. fusca YX. Approximately 95% of the original activity remained after treatment at 50°C for 3 h. and approximately 75% of the original activity remained after treatment at pH 10.0 for 24 h. This laccase could oxidize dye intermediates, especially 2,6-dimethylphenylalanine and p -aminophenol, to produce coloring. This is the first report on laccase properties from thermophilic actinomycetes. These properties suggest that this newly isolated laccase has potential for specific industrial applications.