The Use of Silica Gels for the Cultivation of Halophilic Organisms

Helen Norris Moore
1940 Journal of Bacteriology  
The cultivation of that group of organisms known as the halophiles has claimed the attention of industrial bacteriologists for some time. Various types of media have been proposed but none have proved completely satisfactory. Rice starch paste, hide and fish digest made solid with agar, coagulated eggs and the classic nutrient agar containing 3 molar sodium chloride have been proposed and used by many workers with indifferent results. The most serious criticisms of these media are (1) slow,
more » ... a are (1) slow, scanty growth; (2) colonies small and hard to see; (3) high pouring temperatures of the agar mixtures; (4) peptization of the agar; (5) difficulty in clarifying, and (6) irregularities in the results. Silicic acid jellies have been used since 1890 for the cultivation of soil organisms. Compared with the media mentioned previously, these gels offer larger pore size, lowered pouring temperatures and the possible presence of more free water to carry nutrients to the cells. With these characteristics, silicic acid gels may provide a particularly advantageous environment for the cultivation of salt-tolerant organisms; and it was to test this possibility that the following experiments were undertaken. Various combinations of inorganic salts and organic materials were prepared in testing the usefulness of the medium. The nutrient salts used by Hanks and Weintraub (1936) were incorporated in the gels together with such organic materials as cystine, peptone, gelatin, and glucose. The sodium chloride content was brought as near as possible to 3 molar, which is accepted as necessary for the growth of true halophilic organisms. 409 on May 9, 2020 by guest
doi:10.1128/jb.40.3.409-413.1940 fatcat:eypekgzdtra6dhipwtfxskg5re