Biochemical studies of morpholine catabolism by an environmental mycobacterium

Abstract

When Mycobacterium strain MorG was grown with morpholine as sole source of carbon and nitrogen, enzymes for ethanolamine catabolism (via the ethanolamine-O-phosphate pathway) and glycollate catabolism (via the glycerate pathway) were strongly induced. Almost all morpholine-negative (Mor-) mutants of MorG failed to utilize glycollate as a carbon source and were shown to be defective in one or more enzymes for its metabolism via the glycerate pathway. Growth of MorG with morpholine also induced the Jacoby and Fredericks pathway for pyrrolidine catabolism, M o r -mutants had invariably lost the ability to grow on pyrrolidine and 2(2-aminoethoxy)acetate was shown to be an intermediate in morpholine catabolism. This indicates that morpholine is initially catabolised by an analogous route to pyrrolidine, producing 2(2-aminoethoxy)acetate which can be oxidatively cleaved to give rise directly to glycollate and indirectly to ethanolamine.

Common Degradative Pathways of Morpholine, Thiomorpholine, and Piperidine by Mycobacterium aurum MO1: Evidence from 1 H-Nuclear Magnetic Resonance and Ionspray Mass Spectrometry Performed Directly on the Incubation Medium

“…strain MORG. These results clearly show that the ethanolamine branch proposed previously (20,24) as a downstream pathway for morpholine degradation is not present. Indeed, cleavage of 2-(2-aminoethoxy)acetate in ethanolamine would be accompanied by production of oxalate without diglycolate.…”

“…Indeed, cleavage of 2-(2-aminoethoxy)acetate in ethanolamine would be accompanied by production of oxalate without diglycolate. Actually, although the enzymes of this pathway branch are naturally present in mycobacteria (24), no intermediate of ethanolamine degradation was found when the cells were incubated with morpholine (7,21). Also, Swain et al (24) showed that only the enzymes of the glycolate branch were knocked out in Mycobacterium sp.…”

“…Actually, although the enzymes of this pathway branch are naturally present in mycobacteria (24), no intermediate of ethanolamine degradation was found when the cells were incubated with morpholine (7,21). Also, Swain et al (24) showed that only the enzymes of the glycolate branch were knocked out in Mycobacterium sp. strain MORG mutants that were not able to degrade morpholine (Mor Ϫ ), while the enzymes of the ethanolamine branch were not modified.…”

Carrageenan: a review

“…in κ-carrageenan, taking advantage of the oxygen gradient inside the entrapment beads (Dos Santos et al 1996a, b). The immobilisation of M. aurum in κ-carrageenan and its use in an air-bubble fermenter resulted in an improvement of its morpholine-degrading capacity (Swain et al 1991;Poupin et al 1996). The carrageenan gel and immobilised microbial cells method was used for 4-chlorophenol degradation (Wang et al 1997).…”

Surface Properties of Bacteria from Different Wastewater Treatment Plants

“…EDTA, morpholin, tetrahydrofuran, dioxane or glycol ethers), or referred to "acknowledged problems" during the biotreatment. Although cultures of naturally occurring organisms capable of degrading these substrates are known [5,6], establishing these bacteria within a degradative community seems to be difficult. Among other factors, incompatible surface properties of the different bacterial strains could be responsible for these problems.…”