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.

    46/582 (page 218)
    CHAPTER LI. CULTIVATION AND REPRODUCTION OF YEAST. § 264.—Hansen’s Method of Single-Cell Culture. In samples of yeast as they reach the laboratory from natural sources or from the fermentation industries, the cells are not infrequently in an enfeebled condition, and therefore need to be reinvigorated before they csn be sowed in the nutrient gelatin employed for making pure cultures. Thus in the case of breweries, for instance, the usual practice adopted for sending yeast samples to a pure-culture laboratory through the post is to place a drop of the thick balm, about the size of a pea at the most, on a sterilised filter-piper, and thus free it from water to a sufficient extent to enable it to be sent, enclosed in several layers of the paper, in an envelope. On reaching the laboratory this desiccated drop is placed in wort, where the cells are revived and regain their full power. The same thing is done in the case of wine lees. The reinvigorated sample is then subdivided, in the manner described below, in order to obtain cultures that are indubitably grown from a single cell, and are therefore teimed “single-cell cultures.” The insecurity of the dilution method has already been pointed out in vol i. (p. 125); and for the purpose of obtaining pure yeast cultures, this method was improved upon by E. (Jiir. Hansen (II.) in 1879. Ilansen had observed that when several cells were present in a culture vessel they settled down separately, when properly stirred, and being devoid of locomotive power, each developed into a colony by itself. In such cases those in which only a single colony developed wer-e alone suitable for the purposes of pure culture. The first six species of Saccharomycetes introduced into the literature by Hansen, namely S. cerevisicv /., S. Pastorianus I-IIT., S. ellipsoideus /. and II., were obtained in this manner. At a later date (1883) Hansen (XII.) made use of the liquefiable solid medium, 10 per cent, wort-gelatin. J. Chr. Holm (IV.), in a critical investigation of the resulting priority controversy, established the fact that this was done by Hansen independently, and especially so with respect to the method of It. Koch. As already stated in vol. i. (p. 132), it is only capable of fur-