Abstract: In order to prepare a large amount of Lcc9, the gene lcc9 was cloned and homologously overexpressed in Corprinopsis cinerea Okayama 7#130 (OK7) and FA2222. A total of 46 OK7-lcc9 and 29 FA2222-lcc9 positive transformants were obtained, respectively, based on the primary screening in regeneration medium and re-screening in minimal medium. After inoculation of 5% (V/V) seed cultures in Kjalke medium and cultured at 37 ℃ for 6-7 d, laccase activity of OK7-lcc9 and FA2222-lcc9 in shaking flasks reached 5.1-21.1 U/mL and 3.7-12.3U/mL, respectively, 19.2 and 241.2 times higher than that of the wild type strains. One of the FA2222 positive strains was cultured in a 3 L fermenter for laccase preparation. Results showed that the laccase activity of the strain reached 59 U/mL after incubation at 37 ℃ and 50 r/min for 108 h, which was 4.8 times higher than that in the liquid shake flask cultures.

Key words: Laccase, Lcc9, Coprinopsis cinerea, homologous overexpression, high-density fermentation