Metabolites of the Anaerobic Degradation of n-Hexane by Denitrifying Betaproteobacterium Strain HxN1.
The constitutions of seven metabolites formed during anaerobic degradation of n-hexane by the denitrifying betaproteobacterium strain HxN1 were elucidated by comparison of their GC and MS data with those of synthetic reference standards. The synthesis of 4-methyloctanoic acid derivatives was accomplished by the conversion of 2-methylhexanoyl chloride with Meldrum's acid. The β-oxoester was reduced with NaBH4 , the hydroxy group was eliminated, and the double bond was displaced to yield the methyl esters of 4-methyl-3-oxooctanoate, 3-hydroxy-4-methyloctanoate, (E)-4-methyl-2-octenoate, and (E)- and (Z)-4-methyl-3-octenoate. The methyl esters of 2-methyl-3-oxohexanoate and 3-hydroxy-2-methylhexanoate were similarly prepared from butanoyl chloride and Meldrum's acid. However, methyl (E)-2-methyl-2-hexenoate was prepared by Horner-Wadsworth-Emmons reaction, followed by isomerization to methyl (E)-2-methyl-3-hexenoate. This investigation, with the exception of 4-methyl-3-oxooctanoate, which was not detectable in the cultures, completes the unambiguous identification of all intermediates of the anaerobic biodegradation of n-hexane to 2-methyl-3-oxohexanoyl coenzyme A (CoA), which is then thiolytically cleaved to butanoyl-CoA and propionyl-CoA; these two metabolites are further transformed according to established pathways.
['Küppers|Julian|J|', 'Mitschke|Nico|N|', 'Heyen|Simone|S|', 'Rabus|Ralf|R|0000-0001-5536-431X', 'Wilkes|Heinz|H|0000-0002-0421-0107', 'Christoffers|Jens|J|0000-0003-1433-6579']
D000693:Anaerobiosis D020562:Betaproteobacteria D001673:Biodegradation, Environmental D008401:Gas Chromatography-Mass Spectrometry D006586:Hexanes D015394:Molecular Structure
anaerobic degradation C−H activation alkanes metabolism structure elucidation