Technical mycology : the utilization of micro-organisms in the arts and manufactures a practical handbook on fermentation and fermentative processes, for the use of brewers and distillers, analysts, technical and agricultural chemists, pharmacists, and all interested in the industries dependent on fermentation / by Franz Lafar ; translated by Charles T.C. Salter.

  • Lafar, Franz, 1865-1938.
Date:
1910-1911
Catalogue details

Licence: In copyright

Credit: Technical mycology : the utilization of micro-organisms in the arts and manufactures a practical handbook on fermentation and fermentative processes, for the use of brewers and distillers, analysts, technical and agricultural chemists, pharmacists, and all interested in the industries dependent on fermentation / by Franz Lafar ; translated by Charles T.C. Salter. Source: Wellcome Collection.

    40/582 (page 212)
    J. Effront (VIII.) is said to employ a nutrient medium con- taining nitrates as the exclusive source of nitrogen. § 263.—Organic Sources of Nitrogen. In the worts, mashes, and musts used in practical fermentation, the yeast has not to depend on inorganic sources of nitrogen, but generally has at its disposal an abundance of readily assimilable organic nitrogen compounds. The suitability of a few represen- tatives of this large class will be more closely considered in the following paragraphs. Among the amides suitable as nitrogenous foodstuffs, special attention is merited by the acid amide of aspartic acid (COOH—CHo— CH.NHo—COOH) namely, asparagin (COOH—CH2—CH.NH2—CO.NH2), this substance playing an important part in the mashes used in practice. It is always formed during the germination of seeds, and is therefore present in malt, and still more abundantly in malt culms. Even potatoes contain appreciable quantities. Finally, in addition to other amides, asparagin is one of the chief forms in which nitrogen occurs in the molasses of beet sugar works; proteins, on the other hand, being almost entirely excluded or eliminated by the method employed for obtaining the juice from the beet in the diffuser and by the purification process in the saturator. M. Hayduck (IV.) recognised asparagin as an excellent source of nitrogen in the nutrition of yeast; and this was confirmed by E. Laurent (VI.), G. Heinzelmann (IY.), H. P. Wijsmann (II.), and others. Yeast is capable of trans- forming asparagin into proteins, a property unshared by the animal organism so far as is known at present. The nitrogen of asparagin (which is worthless as a food for animals) is present in the potatoes made into distilleiy mash, is recovered in the distillery waste in the form of protein, and imparts to this waste product the character of a concentrated fodder for stall-fed cattle. In an experiment carried out by P. Petit (II.) with a nutrient medium containing asparagin and ammonium phosphate, it was found that top-fermentation yeast consumed twice as much of the former as was utilised by bottom yeast—a difference con- sidered by the author to afford a means of differentiating these two yeasts. According to a comparison instituted by R. Kus- serow (I.), on the relative influence of asparagin and peptone as the source of nitrogen in saccharified mineral nutrient solutions, the former substance accelerates fermentation and increases the yeast crop. The observation that when grown with the aid of asparagin, the cells of the sedimental yeast are not cohesive,