Ferments and their actions / by Carl Oppenheimer ; Translated from the German by C. Ainsworth Mitchell.

Date:
1901
Catalogue details

Licence: In copyright

Credit: Ferments and their actions / by Carl Oppenheimer ; Translated from the German by C. Ainsworth Mitchell. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    CH3CH2OH + 20 = CH3. COOH + H20, in which we must conclude that there is an intermediate formation of acetaldehyde, CH3. OHO. The fermentative reaction strictly follows the course here represented, for the fact that small quantities of aldehyde can invariably be detected is not due to a secondary simultaneous process, but only represents the momentary stage in the course of the reaction, in which a production and further oxidation of the aldehyde is continually taking place. The conditions under which the production of vinegar proceeds belong, in the main, to the consideration of the influence of micro-organisms in general; it only takes place in dilute solu- tions of alcohol, thriving best at 25° to 30° 0., is very slow below 10° C. and above 35° C., and completely stops at a temperature but little higher than this.1 2 The Biology of the Acetic Fermentation.—As the liquids become sour a pellicle is formed upon them, the so-called mother- of vinegar, which Liebig regarded as the ferment, which, in its decomposition, effected the transference of oxygen. This pellicle, however, was discovered, first by Kutzing 2 and then bv Thomson,3 to be composed of living vegetable cells, which were subsequently described, notably by Pasteur,4 under the name of Mycoderma aceti, and regarded as the effective cause of the acetic fermentation. Since, however, the name mycoderma would indicate a relationship with the budding-fungi, which form similar pellicles upon alcoholic liquids without inducing acetic fermentation, the organisms which cause that fermentation have been grouped, in accordance with Zopf’s proposal, under the generic name Bacterium, which indicates their true position among the fission-fungi. A whole series of such acetic bacteria are now known. Besides the B. aceti, there are also recognised B. Pasteurianum, B. Kuetzingianum (Hansen5), B. oxidans, B. acetosum, B. acetigenum, Termobacterium aceti, and many others.6 1 By acclimatisation to a different method of manufacture, acetic bacteria in England thrive best at a much higher temperature—40° to 44° C. —Translator. 2 Kutzing, J. pr. Ch., xi., 390. 3 Thomson, Ann. Chem. Pharm., lxxxiii., 89, 1852. 4 Pasteur, see in particular Etudes sur le Vinaigre, Paris, 1896. 5 Hansen, Untersuch. a. d. Technik. d. Gahrungsgewerbes, 1895. 6 Cf., inter alios, Wermischeff, Ann. Past., 213, 1893; Henneberg, C.f. Baht., [2], iv., 14, 71, 1898; Hoyer, ibid., 867; Chem. Centralbl., i., 854, 1899.