Bacterial Metabolism

Abstract

THE chemical action of bacteria (and other micro-organisms) has always aroused great interest for two reasons. The weight of material which undergoes change frequently stands in striking disproportion to the weight of the organisms which provoke the change, and the products, in contrast to the few simple end substances formed by the oxidation of food materials in the animal body, are diverse in kind and often complex in nature. The clue to the explanation of these phenomena lies in the fact that bacteria and many other micro-organisms possess, in addition to the aerobic mode of life in which food materials are oxidised by the aid of atmospheric oxygen, the faculty of acquiring the special compounds requisite for growth and the energy for both growth and maintenance by an anaerobic process. In this atmospheric oxygen is not involved, since it consists in producing a rearrangement of the atoms of the food materials so that the resulting compounds, often of a highly complex nature, contain less energy than those from which they have been formed. This process, known generally as fermentation results, as was first pointed out by Lavoisier, in the transference of oxygen and hydrogen from one atom to another in such a way that one part of the molecule becomes oxidised and another reduced, the bonds between the carbon atoms being often simultaneously broken, so that a number of smaller molecules are produced.

Bacterial Metabolism.

Marjory Stephenson. (Monographs on Biochemistry.) Pp. xii + 320. (London, New York and Toronto: Longmans, Green and Co., Ltd., 1930.) 18s. net.