白腐菌液体和固体培养产生木质纤维素降解酶的比较研究

Comparative studies on lignocellulolytic enzyme production in liquid and solid cultures of white-rot fungi

侧耳sp2(Pleurotus sp．2)和粗毛栓菌(Trametes gallica)是产木质纤维素降解酶能力强,且产酶较快的菌株。对其在液体培养基、固体培养基中产生木质纤维素降解酶能力和行为进行了比较分析和研究。结果表明,Pleurotus sp．2在低氮高碳高无机盐培养基中的锰过氧化物酶(Manganese peroxidases, MnPs)、木质素过氧化物酶(Lignin peroxidases．LiPs)、漆酶(laccases,Lacs)和半纤维素酶(Hemicellulases, Hcels)的活性最高。当该菌株培养在含有低氮无碳高无机盐液体培养基的麦草粉中时,MnPs和Lacs的活性峰值均出现在10d,而Hcels的活性在40d时达到峰值。Trametes gallica在高氮低碳高无机盐培养基中的Lacs和LiPs的活性最高,在低氮高碳高无机盐培养基中的MnPs和Hcels的活性最高。当该菌株培养在含有高氮无碳高无机盐和低氮无碳高无机盐液体培养基的麦草粉中时,MnPs存10d、Lacs和Hcels在40d、LiPs存50d,分别达到峰值。Pleurotus sp．2和Trametes gallica在液体培养基中具有很强的木质纤维素降解酶产生能力且产酶速度较快,在固体培养基中具有很强的降解麦秸生物质能力,但这两株菌在液体和固体培养基中,产木质纤维素降解酶的能力和行为都有较大的差异,相关性小。

Pleurotus sp.2 and Trametes gallica are high-yield strains producing lignocellulolytic enzymes and the enzyme production can peak at an early stage of fermentation of the strains. Comparative studies on lignocellulolytic enzyme production in liquid and solid culture of the strains were conducted. The results indicated that the enzyme activities of manganese-dependent peroxidases（MnPs）, lignin peroxidases（LiPs）, laccases（Lacs）, and hemicellulases（Hcels） were the highest in Pleurotus sp.2 growing on low-nitrogen, high-carbon and high inorganic salt medium. MnPs produced by Pleurotus sp：2 reached the peak in six days. When Pleurotus sp.2 was incubated in wheat straw powder containing the liquid medium of low-nitrogen, no-carbon and high inorganic salt, the activities of manganese-dependent peroxidases and laccases reached the peaks on the tenth day, but the activities of hemicellulases reached the peak on the 40th day. The enzyme activities of laccases and lignin peroxidases were the highest in Trametes gallica growing on high-nitrogen,low-carbon and high inorganic salt medium, and the enzyme activities of manganese-dependent peroxidases, and bemicellulases were the highest in the fungus growing on low-nitrogen, high-carbon and high inorganic salt medium. When T. gallica was incubated in wheat straw powder containing liquid medium of high-nitrogen, no-carbon and high inorganic salt and containing liquid medium of low-nitrogen, no-carbon and high inorganic salt, the activities of manganese-dependent peroxidases reached the peaks on the tenth day, the activities of laccases and hemicelluloses reached the peaks on the 40th day, and the activities of lignin peroxidases reached the peaks on the 50th day. Facts have proved that Pleurotus sp.2 and Trametes gallica may be excellent candidate strains in biopulping of paper industry. It was shown that the lignocellulolytic enzyme activities produced by and the biomass-degrading ability of Pleurotus sp.2 and T. gallica were high and the highest enzyme activity appeared at the early stage of solid-state fermentation. However, the enzyme-producing mechanisms of the two incubating modes were different.