FOR 1530: Anaerobic Biological Dehalogenation: Organisms, Biochemistry and (Eco-)Physiology

在许多地点都可以检测到卤代烃。它们可能是自然的或人为的。特别是那些由人类活动释放到环境中的卤代化合物通常具有生态危害性、毒性和/或致癌性;此外，挥发性卤代化合物破坏我们星球的臭氧层。卤化化合物，如四氯乙烯（PCE），在污染场地通常是不可降解的，因为它们的降解或脱卤速度都很低。在这些场所，高氯化化合物（如四氯乙烯）的生物脱氯是由严格意义上的厌氧细菌进行的，这些细菌能够在没有氧气的情况下用卤代烃进行呼吸（有机卤化物呼吸）。在这种呼吸过程中，卤代化合物被还原脱卤。这个过程与ATP的合成相结合，意味着能量守恒。该研究股将侧重于有机卤化物呼吸。在这项研究的过程中，将调查这种新型无氧呼吸的所有重要方面。这些方面包括生理和生化催化机制以及能量守恒机制、呼吸链的结构和拓扑结构以及所涉及的组分的调节。这些研究的先决条件是了解有机卤化物呼吸细菌的基因组。一些基因组序列已经知道并发表，其他的将作为研究单位的一部分在研究项目中公布。在这些序列的基础上，有机卤化物呼吸链的组成部分可以在适当的实验条件下进行鉴定，并可以在以后进行更详细的表征。计划中的研究将有助于一方面了解有机卤化物的呼吸作用及其在全球卤素循环中的作用，另一方面将有助于应用这一过程对受卤化化合物污染的场地进行生物修复。

Halogenated hydrocarbons can be detected at many sites. They may be of natural or anthropogenic origin. Especially those halogenated compounds released into the environment by human activities are often ecologically harmful, toxic, and/or carcinogenic; moreover, volatile halogenated compounds destroy the ozone layer of our planet. Frequently halogenated compounds such as tetrachloroethene (PCE) are widely recalcitrant at contaminated sites, since they are degraded or dehalogenated, respectively, only at rather low rates. The biological dechlorination of highly chlorinated compounds, e.g. PCE, at such sites is performed by strictly anaerobic bacteria that are able to respire with halogenated hydrocarbons (organohalide respiration) in the absence of oxygen. In the course of this respiration, the halogenated compounds are reductively dehalogenated. This process is coupled to the synthesis of ATP, meaning energy conservation. The Research Unit will focus on the organohalide respiration. In the course of this research, all significant aspects of this novel type of anaerobic respiration will be investigated. These aspects comprise the physiology and biochemical catalytic mechanisms as well as the mechanisms of energy conservation, the structure and topology of the respiratory chain and the regulation of the components involved. A prerequisite for these studies is the knowledge of the genomes of organohalide-respiring bacteria. A few genome sequences are already known and published, others will be revealed in the research projects as parts of the Research Unit. On the basis of these sequences, the components of the organohalide respiratory chain may be identified under appropriate experimental conditions and may later be characterised in more detail. The planned studies will contribute, on the one hand, to the understanding of the organohalide respiration and its role in the global halogen cycle and, on the other hand, to the application of this process for the bioremediation of sites contaminated with halogenated compounds.