Guar gum: a cheap substitute for agar in microbial culture media.
OBJECTIVE
To determine the possibility of using guar gum, a colloidal polysaccharide, as a cheap alternative to agar for gelling microbial culture media.


RESULTS
As illustrative examples, 12 fungi and 11 bacteria were cultured on media solidified with either guar gum or agar. All fungi and bacteria exhibited normal growth and differentiation on the media gelled with guar gum. Microscopic examination of the fungi and bacteria grown on agar or guar gum gelled media did not reveal any structural differences. However, growth of most of the fungi was better on guar gum media than agar, and correspondingly, sporulation was also more advanced on the former. Bacterial enumeration studies carried out for Serratia sp. and Pseudomonas sp. by serial dilution and pour-plate method yielded similar counts on both agar and guar gum. Likewise, a selective medium, succinate medium used for growth of Pseudomonas sp. did not support growth of Bacillus sp. when inoculated along with Pseudomonas on both agar or guar gum supplemented medium.


CONCLUSIONS
Guar gum, a galactomannan, which is 50 times cheaper than Difco-bacto agar, can be used as a gelling agent in place of agar in microbial culture media.


CONCLUSIONS
As the media gelled with guar gum do not melt at temperature as high as 70 degrees C, these can be used for isolation and maintenance of thermophiles.
Jain
R
R
Department of Botany, University of Delhi, Delhi, India.
Anjaiah
V
V
Babbar
S B
SB
D000362:Agar; D001419:Bacteria / Q000254:growth & development*; D003470:Culture Media; D005658:Fungi / Q000254:growth & development*; D005685:Galactans; D008351:Mannans; D008828:Microbiological Techniques; D053149:Plant Gums
D003470:Culture Media; D005685:Galactans; D008351:Mannans; D053149:Plant Gums; D000362:Agar; C007894:guar gum