Improved expression of Cerrena unicolor Laccase in Aspergillus niger via combined strategies and its applications

• Published in: Biochemical engineering journal 2024-09, Vol.209, p.109371, Article 109371
• Main Authors: Huang, Jiang, Wang, Jun, Chen, Li-zhi, He, Jin-ling, Wu, Yu-peng, Cui, Xi-peng, Mei, Meng-ning, Li, Yang-yuan
• Format: Article
• Language: English
• Subjects: aflatoxin B1; ambient temperature; ARTP; Aspergillus niger; biotechnology; Cerrena unicolor; decolorization; denim; enzyme activity; fermenters; genes; heterologous gene expression; indigo; industry; Laccase; Methyl syringate; mutagenesis; Mycotoxin degradation; zearalenone
• ISSN: 1369-703X; 1873-295X
• DOI: 10.1016/j.bej.2024.109371

The application of laccases in biotechnology and industry is an expanding research field. Laccases derived from Cerrena unicolor (C. unicolor) exhibit notable potential in the food and industrial sectors. However, generating sufficient yields of this laccase through heterologous expression to meet commercial demands remains a challenge. Therefore, we heterologously expressed LACCASE2 (Lac2), a laccase gene from C. unicolor, in Aspergillus niger. By incorporating strategies such as codon optimization, molecular chaperone-assisted expression, and atmospheric and room-temperature plasma (ARTP) mutagenesis, we successfully screened the strain OPT-HacA-M10 with the highest laccase yield, which exhibited a remarkable enzymatic activity of 416.8 U/mL in a 50-L fermenter. We further assessed the enzymatic properties of the recombinant laccase rLac2, focusing on its capabilities in dye decolorization and mycotoxin degradation. In the absence of a mediator, rLac2 exhibited extremely high degradation efficiency for Remazol Brilliant Blue R and indigo. Impressively, outstanding results were achieved with this laccase in denim bleaching. In mycotoxin degradation tests, with methyl syringate as a mediator, rLac2 achieved degradation rates of over 94% for aflatoxin B1 and zearalenone. In summary, due to its heightened laccase activity and versatile applications, our enhanced strain is highly suitable for industrial and food sectors. •This is the first report in which laccase yield was enhanced in A. niger through this strategy.•The findings of this study delineate an efficient method for the heterologous expression of laccase in A. niger.•The findings of this study furnish insights for amplifying protein production within heterologous platforms.•Our optimized strain is exceptionally suited for applications in the industrial and food sectors.