Paszczyński Andrzej, Crawford Ronald L, Blanchette Robert A
Department of Bacteriology and Biochemistry, College of Agriculture, University of Idaho, Moscow, Idaho 83843, and Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota 55108.
Appl Environ Microbiol. 1988 Jan;54(1):62-68. doi: 10.1128/aem.54.1.62-68.1988.
Kraft pulps, prepared from softwoods, and small chips of birch wood were treated with heme and tert-butyl hydroperoxide in aqueous solutions at reflux temperature. Analyses of treated pulps showed decreases in kappa number (a measure of lignin content) from about 36 to less than 2, with concomitant increases in brightness (80% increase in the better samples). Analyses of treated wood chips revealed selective delignification and removal of hemicelluloses. After 48 h of treatment, lignin losses from the wood chips approached 40%, and xylose/mannose (hemicellulose) losses approached 70%, while glucose (cellulose) losses were less than 10%. Examination of delignified chips by transmission electron microscopy showed that the removal of lignin occurred in a manner virtually indistinguishable from that seen after decay by white rot fungi. Various metalloporphyrins, which act as biomimetic catalysts, were compared to horseradish peroxidase and fungal manganese peroxidase in their abilities to oxidize syringaldazine in an organic solvent, dioxane. The metalloporphyrins and peroxidases behaved similarly, and it appeared that the activities of the peroxidases resulted from the extraction of heme into the organic phase, rather than from the activities of the enzymes themselves. We concluded that heme-tert-butyl hydroperoxide systems in the absence of a protein carrier mimic the decay of lignified tissues by white rot fungi.
由软木制备的硫酸盐浆以及桦木小碎片在水溶液中于回流温度下用血红素和叔丁基过氧化氢处理。对处理后的纸浆分析表明，卡伯值（木质素含量的一种度量）从约36降至小于2，同时亮度增加（较好样品中增加80%）。对处理后的木片分析显示有选择性的脱木质素以及半纤维素的去除。处理48小时后，木片中木质素损失接近40%，木糖/甘露糖（半纤维素）损失接近70%，而葡萄糖（纤维素）损失小于10%。通过透射电子显微镜对脱木质素木片的检查表明，木质素的去除方式与白腐真菌腐朽后所见的方式几乎无法区分。将各种作为仿生催化剂的金属卟啉在有机溶剂二氧六环中氧化丁香醛连氮的能力与辣根过氧化物酶和真菌锰过氧化物酶进行了比较。金属卟啉和过氧化物酶表现相似，并且过氧化物酶的活性似乎是由于血红素萃取到有机相中，而不是酶本身的活性所致。我们得出结论，在没有蛋白质载体的情况下，血红素 - 叔丁基过氧化氢体系模拟了白腐真菌对木质化组织的腐朽。
