The microbial degradation of morpholine

Abstract

Morpholine can be completely degraded microbiologically, and two organisms have been isolated, each capable of growth in a simple mineral salts medium with morpholine as the sole source of carbon, nitrogen and energy. Excess nitrogen is liberated as ammonia. The enzymes responsible for the oxidation of morpholine are inducible and, in organism Mor G, will also oxidize piperidine, piperazine and pyrrolidine, which are not growth substrates. Ethanolamine is a likely intermediate, though the metabolic steps in morpholine degradation do not give rise solely to acetyl‐CoA. After a period of acclimation, a laboratory scale activated sludge plant effectively removed morpholine over the long period it was operated; the sludge was also capable of nitrification. The possible effects of other chemicals in trade wastes containing morpholine on nitrification and morpholine oxidation are described.

High morpholine degradation rates and formation of cytochrome P450 during growth on different cyclic amines by newly isolated Mycobacterium sp. strain HE5 The EMBL accession number of the 16S rRNA gene of Mycobacterium sp. strain HE5 is AJ012738.

“…2). A similar stoichiometry was obtained at 20, 30, 40 and 50 mM morpholine, being different to the ratio of 1 : 0n82 and 1 : 0n94 determined for M. aurum MO1 and strain MorG, respectively (Knapp et al, 1982 ;Mazure & Truffaut, 1994 ;Swain et al, 1991). the morpholine-containing mineral salts medium.…”

“…During growth of the organism, the concentration of morpholine in the mineral salts medium was determined by a colorimetric assay using naphthoquinone sulfonic acid (Knapp et al, 1982). Alternatively, the concentration of morpholine and other growth substrates was estimated by GC analysis using a gas chromatograph 14-B (Shimadzu), a flameionization detector and capillary column BGB-1701 (SCP Seitz, length 30 m, inside diameter 0n25 mm, film thickness 0n25 µm).…”

“…Combourieu et al (1998) used "H NMR spectroscopy for a direct detection of morpholine and they were able to identify 2-(2-aminoethoxy)acetate as an intermediate of morpholine degradation, demonstrating that the initial ring cleavage occurred at the C-N bond. However, little is known about the enzymes catalysing these initial steps (Knapp et al, 1982 ;Cech et al, 1988 ;Knapp & Brown, 1988 ;Brown & Knapp, 1990 ;Swain et al, 1991 ;Emtiazi & Knapp, 1994 ;Mazure & Truffaut, 1994). Recently, evidence was presented for a cytochrome P450 to be involved in the initial oxidation of morpholine by an environmental Mycobacterium strain .…”

“…co-metabolizing morpholine in the presence of succinate. A common feature of morpholine-utilizing cultures is their slow growth (µ max 0n05-0n07 h −" ), disadvantageous for potential biotechnological applications (Knapp et al, 1982 ;Cech et al, 1988 ;Knapp & Brown, 1988 ;Mazure & Truffaut, 1994 ;Poupin et al, 1996Poupin et al, , 1998. Hypothetical pathways have been proposed for the microbial biodegradation of morpholine (Swain et al, 1991 ;Mazure & Truffaut, 1994 ;Combourieu et al, 1998).…”

Removal of Selected Benzothiazols with Ozone

“…Moreover, they can be absorbed onto cell membranes, leading to bioaccumulation (Gaja & Knapp, 1998). According to Knapp et al (1982), 7.0 mg.l -1 BT causes a 50% and 54 mg.l -1 a 100% inhibition of ammonia oxidation, while nitrate utilization is not affected (de Wever and Verachter, 1997). Tomslino et al (1966) proved 75% inhibition of ammonium nitrogen oxidation at the concentration of 3 mg.l -1 MBT.…”