Sphingomonas herbicidovorans MH: a versatile phenoxyalkanoic acid herbicide degrader

Abstract

Sphingomonas herbicidovorans MH was isolated from a dichlorprop-degrading soil column. It is able to grow on phenoxyalkanoic acid herbicides, such as mecoprop, dichlorprop, 2,4-D, MCPA, and 2,4-DB. Strain MH utilizes both enantiomers of the chiral herbicides mecoprop and dichlorprop as sole carbon and energy sources. Enantiomer-specific uptake systems are responsible for transporting the acidic substrates across the cell membrane. Catabolism is initiated by two enantiomer-specific alpha-ketoglutarate-dependent dioxygenases that catalyze the cleavage of the ether bond of the respective enantiomer to yield the corresponding phenol and pyruvate. Therefore selective degradation of the enantiomers of mecoprop and dichlorprop by strain MH is not only due to enantioselective catabolism but also to enantioselective transport.

Diversity of 2,4-Dichlorophenoxyacetic Acid (2,4-D) and 2,4,5-Trichlorophenoxyacetic Acid (2,4,5-T)-Degrading Bacteria in Vietnamese Soils

“…Previously, a S. herbicidovarans MH has been described that degrades phenoxyalkanoic acid herbicides such as mecorprop, dichlorprop, 2,4-D, 4-chloro-2-methylphenoxyacetic acid (MCPA), and 2,4-dichlorophenoxybutanoic acid (2,4-DB) 20,24) , although this strain could not degrade 2,4,5-T 20) . In this study, group S(III) strains, most homologous with S. herbicidovarans, were isolated as 2,4,5-T-degraders.…”

Mineralization of Individual Congeners of Linear Alkylbenzenesulfonate by Defined Pairs of Heterotrophic Bacteria

“…7), and preliminary data from H.-P. E. Kohler (EAWAG, Dübendorf, Switzerland) (personal communication) indicate that C. testosteroni KF-1 utilizes 3-C4-SPC enantiomer specifically. It seems likely that many SPCs are utilized enantiomer specifically, but the mechanisms involved (two enantiomer-specific transport systems and two enantiomer-specific oxygenases, as described by Kohler [19]) remain to be explored. The degradative pathway(s) for SPCs was the subject of much speculation (3) until Schulz et al (32) showed the involvement of inducible 4-sulfocatechol 1,2-dioxygenase in the degradation of 2-C4-SPC and Dong et al (5) found high activity of the enzyme in a mixed culture which degraded SP(d)Cs.…”

Purification and Characterization of Two Enantioselective α-Ketoglutarate-Dependent Dioxygenases, RdpA and SdpA, fromSphingomonas herbicidovoransMH

“…However, both enantiomers were and still are applied as racemic mixtures, resulting in the introduction of large amounts of unwanted chemicals into the environment (10,50,51). Sphingomonas herbicidovorans MH, an Alphaproteobacterium, is able to grow on both enantiomers of mecoprop and dichlorprop, as well as on 2,4-D, as sole carbon and energy sources (21,24,54). In batch cultures, this organism degrades the two enantiomers of mecoprop and dichlorprop sequentially, and the (S) enantiomers are degraded first (25,32).…”