Journal
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
Volume 87, Issue 3, Pages 1023-1031Publisher
SPRINGER
DOI: 10.1007/s00253-010-2507-5
Keywords
Multicopper oxidase; Alkaline laccase; Gene cloning; Enzyme characterization; Metagenome
Categories
Funding
- National Natural Science Foundation of China [30970107]
- National High Technology Research and Development Program of China (863 Program) [2007AA10Z308]
- Science and Technology Plan Project of Guangdong province [2007A010900001]
- Sun Yat-sen University [2007-33000-1132628]
Ask authors/readers for more resources
Lac591, a gene encoding a novel multicopper oxidase with laccase activity, was identified through activity-based functional screening of a metagenomic library from mangrove soil. Sequence analysis revealed that lac591 encodes a protein of 500 amino acids with a predicted molecular mass of 57.4 kDa. Lac591 was overexpressed heterologously as soluble active enzyme in Escherichia coli and purified, giving rise to 380 mg of purified enzyme from 1 l induced culture, which is the highest expression report for bacterial laccase genes so far. Furthermore, the recombinant enzyme demonstrated activity toward classical laccase substrates syringaldazine (SGZ), guaiacol, and 2, 6-dimethoxyphenol (2, 6-DMP). The purified Lac591 exhibited maximal activity at 55A degrees C and pH 7.5 with guaiacol as substrate and was found to be stable in the pH range of 7.0-10.0. The substrate specificity on different substrates was studied with the purified enzyme, and the optimal substrates were in the order of 2, 6-DMP > catechol > alpha-naphthol > guaiacol > SGZ > 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid). The alkaline activity and highly soluble expression of Lac591 make it a good candidate of laccases in industrial applications for which classical laccases are unsuitable, such as biobleaching of paper pulp and dyestuffs processing.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available