FUNGAL DEGRADATION OF CHEMICAL WARFARE AGENTS

根据1997年4月29日生效的《禁止化学武器公约》，化学武器应在10年内销毁。包括日本在内的65个以上国家批准了该条约。在许多种类的化学武器中，被发现生产和储存最多的化学武器是二氯乙基硫醚，也被称为亚硝石或芥子气。亚硝石具有明显的细胞毒性，也是一种致癌和致突变的烷基化剂。1990年开始大规模焚烧黄铁矿。然而，在焚烧中和过程中，出现了一些缺陷。作为焚烧的替代方法，人们提出了几种方法。由于对环境的影响最小和成本效益高，生物修复工艺被认为比其他传统工艺更有利。担子菌是唯一已知的能够完全降解木材成分的生物，包括木质素，木质素是最难降解的芳香生物材料之一。降解木质素的担子菌被称为白腐菌，其他的被称为褐腐菌。利用木质素降解的能力，真菌生物修复已被应用于三硝基甲苯、氯酚、氯化二苯并对二恶英和多环烃等。在本研究中，我们启动了白腐和褐腐担子菌对硫代二甘醇（TDG；亚白石的水解产物）的生物降解。它们表现出很强的代谢TDG的能力，无论是为了消除异种生物还是为了满足硫的需求。然后，为了阐明反应机理，使用了苯硫醚，显示出有效的硫化物键裂解。最后，尝试了真菌对亚硝石的降解。亚角石通过中间形成半亚角石而非酶水解生成TDG。白腐菌和褐腐菌进一步代谢TDG。乙二醇和巯基乙醇被确定为代谢中间体。真菌能够利用TDG和硫醇作为硫源进行生长；因此，TDG在不含硫的介质中被催化降解。少

According to the Chemical Weapons Convention (effective on the 29th of April, 1997), chemical weapons should be destroyed within ten years. More than 65 countries, including Japan, have ratified the Treaty. Among many types of chemical weapons, the agent which has been the most produced and stored was found to be bis(2-chloroethyl) sulfide, also known as Yperite or mustard gas. Yperite is markedly cytotoxic and is also a carcinogenic and mutagenic alkylating agent. Large-scale incineration of Yperite was started in 1990. However, during incineration and neutralization, the occurrence of several drawbacks has been pointed out. As an alternative to incineration, several methods have been proposed. The bioremediation process has been thought to be advantageous over other conventional processes because of a minimal impact on the environment and of cost effectiveness. Basidiomycetes are the only known organisms to completely degrade wood components including lignin, one of the most recalcit … More rant aromatic biomaterials. Lignin-degrading basidiomycetes are called white-rot fungi, and the others are called brown-rot fungi. Utilizing the ability of lignin degradation, fungal bioremediation has been applied to trinitrotoluene, chlorophenols, chlorinated dibenzo-p-dioxins, and polycyclic hydrocarbons etc.In this study, we initiate the biodegradation of thiodiglycol (TDG ; hydrolyzed product of Yperite) by either white-rot or brown-rot basidiomycetes. They exhibited a strong ability to metabolize TDG either for xenobiotic elimination or for sulfur demand. Then, to elucidate reaction mechanisms, benzyl sulfide was utilized, showing effective cleavage of sulfide bond. Finally, the fungal degradation of Yperite was attempted. Yperite was non-enzymatically hydrolyzed to produce TDG via the intermediate formation of a half-Yperite. TDG was further metabolized by both white- and brown-rot fungi. Ethylene glycol and mercaptoethanol were identified as metabolic intermediates. Fungi were capable of utilizing TDG and mercapto-ethanol as a sulfur source for their growth ; therefore, the degradation of TDG was stimulated in non-sulfur containing media. Less