Vane Christopher H, Drage Trevor C, Snape Colin E
British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG, United Kingdom.
J Agric Food Chem. 2003 Feb 12;51(4):947-56. doi: 10.1021/jf020932h.
The chemical transformations that occur during growth of the shiitake mushroom (Lentinula edodes) on oak (Quercus alba) were investigated to improve mushroom cultivation and utilization of the spent substrate. Oak logs were decayed by L. edodes over 8 years, during which time they were sampled at six intervals (30, 40, 66, 76, 77, and 101 months). Fresh and decayed oak samples were analyzed using solid-state (13)C NMR and pyrolysis-gas chromatography-mass spectrometry as well as off-line thermochemolysis with tetramethylammonium hydroxide. Degraded oak exhibited lower carbon contents and increased oxygen content compared to the control. Solid-state (13)C NMR analysis revealed that polysaccharides were the major component of both fresh and decayed oak but that L. edodes mediated the preferential loss of cellulose and xylans as compared to lignin, which remained in an altered form. Several trends point toward the degradation of lignin, including a decrease in the proportion of syringyl units as compared to guaiacyl units and a reduction in side-chain length. An increase in guaiacyl and syringyl acid-to-aldehyde ratios occurred with growth, which suggested that the fungus had caused oxidation of Calpha-Cbeta bonds. The overall effect of L. edodes on oak is similar to that of many white-rot fungi, which simultaneously degrade all cell wall components.
为了改进香菇（Lentinula edodes）的栽培方法以及提高对废弃培养料的利用率，研究了香菇在橡木（Quercus alba）上生长过程中发生的化学转化。橡木原木在8年的时间里被香菇分解，在此期间，每隔一段时间（30、40、66、76、77和101个月）进行一次采样。对新鲜和腐烂的橡木样本使用固态（13）C核磁共振、热解气相色谱-质谱以及用氢氧化四甲铵进行离线热化学降解分析。与对照相比，降解后的橡木碳含量降低，氧含量增加。固态（13）C核磁共振分析表明，多糖是新鲜橡木和腐烂橡木的主要成分，但香菇介导了纤维素和木聚糖相对于木质素的优先损失，木质素以改变后的形式留存。包括丁香基单元与愈创木基单元比例降低以及侧链长度缩短在内的几个趋势表明了木质素的降解。随着生长过程，愈创木基和丁香基酸与醛的比例增加，这表明真菌导致了α-碳- β-碳键的氧化。香菇对橡木的总体影响与许多白腐真菌相似，它们同时降解所有细胞壁成分。
