木材腐朽真菌定向降解木质素为苯系芳香类化学品

对2种木材腐朽真菌降解木质素为一系列苯系芳香类化学品进行了初步研究,并与黄孢原毛平革菌进行了比较。从木材腐朽土壤样品中分离获得具有降解木质素活性的真菌11株,将其中活性最强的菌株ZS1与ZSH用于降解工业碱木质素与中性木质素。通过发酵条件的优化、降解产物种类与浓度的HPLC分析,结果发现,在初始底物浓度1.0～20.0g/L变化时,ZS1对碱木质素的降解率达到40.7%,比ZSH的大;而ZSH对中性木质素的降解率为32.3%,与黄孢原毛平革菌的降解能力相当,但比ZS1的大些。木质素能被定向降解为香草酸、苯甲酸、香草醛、苯酚、紫丁香醛、苯、对甲基苯甲醚、对甲基苯乙醚、甲苯与对二甲苯等芳香类化学品,而且不同真菌降解不同木质素的产物种类数量与浓度有所差异。这说明不同真菌对木质素的降解具有一定的底物依赖性,底物结构差异影响了降解率不同与产物种类差异,而且不同真菌降解木质素具有一定的产物定向选择性。

Aromatic benzene derivatives decomposed from lignin by wood decay fungi

Compared with Phanerochaete chrysosporium Burdsall, a series of benzene aromatic chemicals derived from lignin decomposed by wood decay fungi were investigated.Eleven fungi with potency of degrading lignin were isolated from decay wood samples, and two of them with the highest degradation ability, ZS1 and ZSH, were used to biodegrade alkali lignin and neutral lignin.Through optimizing biodegradation condition and HPLC analysis of degraded products, it was found that, within initial concentrations of 1.0-20.0 g/L, at most 40.7% alkali lignin could be decomposed by ZS1 which is higher than ZSH, while decomposition rate of neutral lignin by ZSH could reach 32.3% which is higher than ZS1.These decomposition rates could be close to that of P.chrysosporium Burdsall.The results also indicated that the lignin could be deconstructed to benzene derivatives chemicals such as vanillic acid, benzoic acid, vanillic aldehyde, phenol, syring aldehyde, benzene, 4-methyl anisole, 4-ethyl anisole, toluene, and p-xylene, which the quantity and concentration of degraded products depended on the type of fungi.The lignin-degrading performance of different fungi showed certain dependency on the structure of substrates, and presented some directional selectivity to products.