Non-conventional gas phase remediation of volatile halogenated compounds by dehydrated bacteria.
Traditional biological removal processes are limited by the low solubility of halogenated compounds in aqueous media. A new technology appears very suitable for the remediation of these volatile organic compounds (VOCs). Solid/gas bio-catalysis applied in VOC remediation can transform halogenated compounds directly in the gas phase using dehydrated cells as a bio-catalyst. The hydrolysis of volatile halogenated substrates into the corresponding alcohol was studied in a solid/gas biofilter where lyophilised bacterial cultures were used as the catalyst. Four strains containing dehalogenase enzymes were tested for the hydrolysis of 1-chlorobutane. The highest removal yield was obtained using the dhaA-containing strains, the maximal reaction rate of 0.8 micromol min(-1)g(-1) being observed with Escherichia coli BL21(DE3)(dhaA). Various treatments such as cell disruption by lysozyme or alkaline gas addition in the bio-filter could stabilise the dehalogenase activity of the bacteria. A pre-treatment of the dehydrated bacterial cells by ammonia vapour improved the stability of the catalyst and a removal activity of 0.9 micromol min(-1)g(-1) was then obtained for 60h. Finally, the process was extended to a range of halogenated substrates including bromo- and chloro-substrates. It was shown that the removal capacity for long halogenated compounds (C(5)-C(6)) was greatly increased relative to traditional biological processes.
Erable
Benjamin
B
UMR 6250 CNRS-ULR, LIENSs, Equipe BIotechnologie ENvironnementale, Bâtiment Marie Curie, Université de La Rochelle, La Rochelle Cedex 1, France.
Goubet
Isabelle
I
Seltana
Amira
A
Maugard
Thierry
T
D000393:Air Pollutants / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D055549:Volatile Organic Compounds / Q000378:metabolism*
D000393:Air Pollutants; D055549:Volatile Organic Compounds