Department of Food and Environmental Sciences, Division of Microbiology, Viikki Biocenter 1, FIN-00014 Helsinki, Finland.
Fungal Biol. 2013 Jan;117(1):62-70. doi: 10.1016/j.funbio.2012.11.006. Epub 2012 Dec 13.
Production of the oxidoreductive lignin-modifying enzymes - lignin and manganese peroxidases (MnPs), and laccase - of the white-rot basidiomycete Phlebia radiata was investigated in semi-solid cultures supplemented with milled grey alder or Norway spruce and charcoal. Concentrations of nutrient nitrogen and Cu-supplement varied also in the cultures. According to extracellular activities, production of both lignin peroxidase (LiP) and MnP was significantly promoted with wood as carbon source, with milled alder (MA) and low nitrogen (LN) resulting with the maximal LiP activities (550 nkat l(-1)) and noticeable levels of MnP (3 μkat l(-1)). Activities of LiP and MnP were also elevated on high nitrogen (HN) complex medium when supplemented with spruce and charcoal. Maximal laccase activities (22 and 29 μkat l(-1)) were obtained in extra high nitrogen (eHN) containing defined and complex media supplemented with 1.5 mM Cu(2+). However, the nitrogen source, either peptone or ammonium nitrate and asparagine, caused no stimulation on laccase production without Cu-supplement. This is also the first report to demonstrate a new, on high Cu(2+) amended medium produced extracellular laccase of P. radiata with pI value of 4.9, thereby complementing our previous findings on gene expression, and cloning of a second laccase of this fungus.
白腐菌 Phlebia radiata 的木质素和锰过氧化物酶（MnP）以及漆酶的氧化还原木质素修饰酶的生产在补充了磨碎的灰桦木或挪威云杉和木炭的半固态培养基中进行了研究。培养基中的营养氮浓度和 Cu 补充剂也有所不同。根据细胞外活性，木质素过氧化物酶（LiP）和 MnP 的生产都显著受到木材作为碳源的促进，磨碎的桦木（MA）和低氮（LN）导致 LiP 活性最高（550 nkat l(-1)）和显著水平的 MnP（3 μkat l(-1)）。当用云杉和木炭补充高氮（HN）复合培养基时，LiP 和 MnP 的活性也升高。在含有 1.5 mM Cu(2+)的高氮（eHN）定义和复合培养基中，可获得最大漆酶活性（22 和 29 μkat l(-1)）。然而，氮源，无论是蛋白胨还是硝酸铵和天冬酰胺，在没有 Cu 补充剂的情况下，都不会刺激漆酶的产生。这也是首次报道在高 Cu(2+) 修正培养基中产生的 Phlebia radiata 的细胞外漆酶，其等电点为 4.9，从而补充了我们之前关于基因表达的发现，并克隆了该真菌的第二种漆酶。
