自带介质血红密孔菌NFZH-1的鉴定及其木质素降解特性

摘要

The process of lignin degradation by white-rot fungi can be intensified by the presence of endogenous mediators. A high-yield laccase-producing fungus with an endogenous mediator is important for the commercial application of laccase. In the present study, we isolated two strains of Pycnoporus sanguineus, namely, NFZH-1 and NFZH-2 from mountain forest region in Nanjing, China, and their laccase production and delignifying characteristics was studied. We also studied these strains in comparison with the best-studied lignin-degrading fungus, Coriolus versicolor. P. sanguineus strain NFZH-1 with an endogenous mediator was identified. Thereafter, NFZH-1 was found to be a high yield laccase-producing strain as determined by the color-reaction and solid-state fermentation. The color zone diameter of NFZH-1 was found to be substantially greater than the mycelia colony one. Moreover, the color zone revealed a dark brown color-reaction using guaiacol as substrate. The laccase activities of P. sanguineus NFZH-1 were found to be 23 600 U/g, while no LiP and MnP were produced in solid-state fermentation. NFZH-1 demonstrated the capability to degrade 56. 7% of Klason lignin and 36. 6% of holocellulose in wheat straw within 30 days of incubation. Our results indicate that P. sanguineus NFZH-1 is a powerful and selective lignin-degrading strain.%菌株自带介质可提高其漆酶降解木质素能力,因此自带介质高产漆酶菌株的筛选、鉴定对漆酶的商业应用将起到促进作用。从南京山林地区分离出两株血红密孔菌NFZH-1和NFZH-2,并以杂色云芝为对照,研究了两株血红密孔菌发酵产漆酶和木质素降解特性。首先通过形态学特性鉴定了NFZH-1为自带介质血红密孔菌。其次以愈创木酚为反应底物,平板接种菌株,培养5天,NFZH-1颜色圈较菌丝圈大,且颜色最深；经10天固态发酵,NFZH-1所产漆酶酶活高达23600 U/g,且未检测出木质素过氧化物酶( LiP)和锰过氧化物酶( MnP)。平板显色和固态发酵产酶结果表明自带介质血红密孔菌NFZH-1为漆酶高产菌株。麦草粉经菌株 NFZH-130天降解,木质素降解率、综纤维素降解率分别达56.7%和36.6%,表明血红密孔菌NFZH-1为选择性高木质素降解活性菌株。