Enrichment of organohalide respiring bacteria. sediment metagenome

Organohalide respiring bacteria are difficult to enrich and isolate, which can limit research on these important organisms. The goal of this research was to develop a method to rapidly (minutes to days) enrich these organisms from a mixed culture or sediment sample. The method presented herein was based on the hypothesis that organohalide respiring bacteria would be more hydrophobic than other bacteria as a result of their niche dehalogenating hydrophobic compounds. To test this hypothesis, a method was developed to separate putative organohalide respiring bacteria at the interface between a hydrophobic organic solvent and aqueous media. This novel separation technique was tested with a sediment-free culture, a tetrachloroethene-enriched digester culture, and sediment from an uncontaminated lake.

有机卤呼吸细菌（organohalide respiring bacteria）的富集与分离难度极高，这一局限制约了对这类重要微生物的相关研究。本研究旨在开发一种可从混合培养物或沉积物样本中快速（数分钟至数天）富集此类微生物的方法。本文所提出的方法基于如下假说：有机卤呼吸细菌因其生存环境中参与脱卤作用的疏水性化合物，会比其他细菌具有更强的疏水性。为验证该假说，本研究开发了一种可在疏水性有机溶剂与水相介质的界面处分离推定有机卤呼吸细菌的方法。本研究采用无沉积物培养物、四氯乙烯（tetrachloroethene）富集型消化器培养物以及未受污染湖泊沉积物，对该新型分离技术进行了测试验证。