Intact-cell detection of halohydrin dehalogenase activity and preliminary assessment of marine adaptability

Halohydrin dehalogenase (HHDH) can degrade 1,2,3-trichloropropanol and other halogenated alcohols. These enzymes exhibit stereoselectivity and can be used to produce pure chiral epoxides and β-substituted alcohols of industrial value. The discovery of novel HHDHs from microorganisms in niche environments including the sea requires analysis of HHDH activity. Owing to its high practical value, HheC was selected as a target enzyme to establish an intact-cell method for detecting HHDH activity based on fluorescence spectroscopy. This approach relied on the principle that HHDH activity can change the pH in a system with weak buffering capacity, and that the fluorescence intensity of certain dyes is influenced by pH. The marine adaptability of the assay was subjected to preliminary investigation. The method is simple, rapid, and highly sensitive, as verified using gas chromatography-mass spectrometry. The detection limit of the method was OD (optical density at a 600 nm) of 0.025 for microorganisms containing HHDH which have activity comparable to that of HheC. With some improvements, this method holds potential for analysis and mining of marine microorganisms containing HHDH.