权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Analysis op-oxidation mchanism of white rot fungi that promate lignin degradation by addition of polyisoprene rubber ; Application to resurce conversion and bioremediation

白腐菌添加聚异戊二烯橡胶促进木质素降解的反氧化机理分析

基本信息

批准号：
12480162
负责人：
WATANABE Takashi
金额：
$ 9.41万
依托单位：
KYOTO UNlVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

Recycling of vulcanized synthetic and natural rubbers is important to avoid environmental problems due to accumulation of the undegradable polymers. To achieve this purpose, degradation of polysulfide bonds in vulcanized rubber is necessary. In this research, we found that a white rot fungus, Ceriporiopsis subvermispora aggressively degraded vulcanized natural rubber sheets (NRS) in the presence of wood. During the cultivation, we also found that addition of NRS markedly accelerated degradation of lignin in the wood. Scanning electron microscopy clearly demonstrated that the surface of the NRS treated by C. subvermispora was intensively damaged. The degradation of NRS was also analyzed by elemental analysis, ESCA and DD/MAS ^<13>C NMR. These analyses demonstrated formation of S-O bonding and decrease in the number of S-C linkage. The fungus preferentially attacked cis-monosulfide bonds. In the degradation of wood by C. subvermispora lipid peroxidation catalyzed by manganese peroxidase (MnP) play a central role. Therefore, MnP was reacted with a fungal metabolite of this fungus, linoleic acid, and the reaction products formed were analyzed by ESR and GC-MS. MnP oxidized linoleic acid to produce acyl radicals. In this reaction, glyoxal was produced as a major aldehyde. The reaction produced chemiluminescent chemical species that is different from singlet oxygen, triplet carbonyl and biacyl triplet. Fluorene and polyisoprene was not degraded by the glyoxal/ MnP system but oxidized by linoleic acid / 1MnP. Thus, aldehyde oxidation was effective for the propagation of chain reactions but the reaction did not produce highly oxidative chemical species. Further research on the mechanisms of free radical reactions is important to establish a new biological and chemical recycling method of rubber.

硫化合成橡胶和天然橡胶的回收利用对于避免由于不可降解聚合物的积累而引起的环境问题是重要的。为了实现这一目的，硫化橡胶中多硫键的降解是必要的。在本研究中，我们发现一种白色腐烂真菌，Ceriporiopsis subvermispora积极降解硫化天然橡胶板（NRS）在木材的存在。在培养过程中，我们还发现添加NRS显著加速木材中木质素的降解。扫描电子显微镜清楚地表明，经C. subvermispora被严重破坏。用元素分析、ESCA和DD/MAS ~ 1C NMR等方法对NRS的降解进行了分析<13>。这些分析表明，形成的S-O键和减少的S-C键的数量。真菌优先攻击顺式单硫键。在C.锰过氧化物酶（MnP）催化亚蠕孢菌脂质过氧化起着重要作用。因此，MnP与该真菌的真菌代谢产物亚油酸反应，并通过ESR和GC-MS分析形成的反应产物。MnP氧化亚油酸产生酰基自由基。在该反应中，乙二醛作为主要醛产生。该反应产生了不同于单线态氧、三重态羰基和双酰基三重态的荧光化学物种。乙二醛/ MnP体系不能降解芴和聚异戊二烯，而亚油酸/1 MnP体系能氧化芴和聚异戊二烯。因此，醛氧化对于链式反应的传播是有效的，但是该反应不产生高度氧化的化学物质。深入研究自由基反应机理，对建立橡胶生物化学回收新方法具有重要意义。