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.

A yellow Gram-negative rod-shaped organism that could grow with ethanolamine, diethanolamine or triethanolamine as the sole source of carbon and energy was isolated from a laboratory-scale activated-sludge plant. Studies with whole cells and cell-free extracts have enabled the inducible pathways for the degradation of these compounds to be elucidated. Triethanolamine is converted, via triethanolamine N-oxide, into diethanolamine and glycolaldehyde; diethanolamine in turn is converted into ethanolamine and glycolaldehyde. Ethanolamine is converted into acetyl units via ethanolamine 0-phosphate and acetaldehyde. In di-and triethanolamine-grown cells the specific activities of glyoxylate carboligase and tartronic-semialdehyde reductase are comparatively high whilst that of isocitrate ly ase is low; this situation is reversed in ethanolamine-grown cells. Triethanolamine-N-oxide dehydroxyethylase appears to be a product-induced enzyme and an inducible transport system may be involved in the uptake of diethanolamine. t Present address:

SUMMARYA heterotrophic bacterium has been isolated which can use thiocyanate as its sole source of cellular nitrogen and also sulphur; ammonium ions inhibit the utilization of thiocyanate. It can utilize both phenol and thiocyanate simultaneously; it is a pseudomonad and is most similar to Pseudomonas stutzeri.

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.

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