Why TCBS agar is not autoclaved?

Why TCBS agar is not autoclaved

Table of Contents


Thiosulfate-citrate-bile salts-sucrose (TCBS) Agar is used for the selective isolation of Vibrio cholerae and other enteropathogenic vibrios. TCBS agar is composed of yeast extract, peptone, sodium thiosulfate, sodium citrate, ox bile (oxgall), sucrose, sodium chloride, iron (III) citrate, bromothymol blue, thymol blue, agar, and distilled or deionized water. TCBS is not autoclaved because:

  • This media contains Ox bile (Oxgall), a derivative of bile salts which inhibit gram-positive bacteria might be sensitive while autoclaving.
  • This agar needs to be boiled and not autoclaved to avoid the caramelization (browning) of sucrose.
  • Autoclaving may precipitate and/or alter the chemistry of the media.


  1. https://www.researchgate.net/post/Why_is_TCBS_media_for_culturing_Vcholerae_not_supposed_to_be_autoclaved_autoclave.
  2. https://microbiologyinfo.com/thiosulfate-citrate-bile-salts-sucrose-tcbs-agar-composition-principle-uses-preparation-and-colony-morphology/
  3. https://www.sciencedirect.com/science/article/pii/S007963520380098X
  4. https://www.chegg.com/tutors/Microbiology-questions/why-we-cannot-autoclave-TCBS-agar–V5TUV/
  5. https://aem.asm.org/content/62/9/3548.full.pdf
  6. https://microbenotes.com/thiosulfate-citrate-bile-salts-sucrose-tcbs-agar/

About Author

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Sagar Aryal

Sagar Aryal is a microbiologist and a scientific blogger. He attended St. Xavier’s College, Maitighar, Kathmandu, Nepal, to complete his Master of Science in Microbiology. He worked as a Lecturer at St. Xavier’s College, Maitighar, Kathmandu, Nepal, from Feb 2015 to June 2019. After teaching microbiology for more than four years, he joined the Central Department of Microbiology, Tribhuvan University, to pursue his Ph.D. in collaboration with Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Saarbrucken, Germany. He is interested in research on actinobacteria, myxobacteria, and natural products. He has published more than 15 research articles and book chapters in international journals and well-renowned publishers.

1 thought on “Why TCBS agar is not autoclaved?”

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