Weihua Qiu, Hongzhang Chen
State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080, PR China.
Bioresour Technol. 2008 Sep;99(13):5480-4. doi: 10.1016/j.biortech.2007.11.014. Epub 2007 Dec 21.
Mycelia Sterilia YY-5, an entophytic fungus, was isolated from Rhus chinensis Mill and its extracellular enzyme had a higher laccase activity (MS-Lac). After been purified by anion exchange and gel filtration chromatography, MS-Lac, which had a molecular mass of 45 kDa, was found to be an alkali-stable enzyme with an optimum pH of 10.0 and capable of retaining 80% activity after incubation for 72 h with syringaldazine as substrate. It was also found that syringaldazine had a higher affinity than 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulphonate (ABTS) as substrate for MS-Lac, which was determined in sodium phosphate buffer (pH 6.0, 0.1M) at 30 degrees C. Meanwhile, the lignin modification, catalyzed by MS-Lac, indicated that it could oxidize the phenolic hydroxyl, side chain substituent or carbonyl group of spruce alkali lignin in cetyltrimethylammonium bromide (CTAB) reversed micelles (20 mM, pH 6.0, W/O=40) and steam-exploded wheat straw alkali lignin in NaOH solution (20 mM, pH 10.0).
无菌丝体YY-5是一种从盐肤木中分离得到的内生真菌，其胞外酶具有较高的漆酶活性（MS-Lac）。经阴离子交换和凝胶过滤色谱纯化后，发现分子量为45 kDa的MS-Lac是一种碱稳定酶，最适pH为10.0，以丁香醛连氮为底物孵育72小时后仍能保持80%的活性。还发现，在30℃的磷酸钠缓冲液（pH 6.0，0.1M）中测定时，丁香醛连氮作为MS-Lac的底物比2,2'-联氮-双-（3-乙基苯并噻唑啉-6-磺酸）（ABTS）具有更高的亲和力。同时，由MS-Lac催化的木质素修饰表明，它可以在十六烷基三甲基溴化铵（CTAB）反胶束（20 mM，pH 6.0，W/O=40）中氧化云杉碱木质素的酚羟基、侧链取代基或羰基，以及在NaOH溶液（20 mM，pH 10.0）中氧化蒸汽爆破麦草碱木质素。
