We want to screen halotolerant protease producing bacteria. Since Skim milk (HiMedia) is available in our lab, therefore, we want to screen extracellular protease by this compound/ supplement. We have followed four papers to make agar medium with skim milk (with 5% NaCl). But every time the media got clotted after autoclave.

What is the reason and solution for this problem? Can anyone suggest anything?

Thank you.

We have followed these papers:

1. Babavalian, H., Amoozegar, M.A., Pourbabaee, A.A. et al. Isolation and identification of moderately halophilic bacteria producing hydrolytic enzymes from the largest hypersaline playa in Iran. Microbiology 82, 466–474 (2013). https://doi.org/10.1134/S0026261713040176

2. Adinarayana, K., Ellaiah, P. & Prasad, D.S. Purification and partial characterization of thermostable serine alkaline protease from a newly isolated Bacillus subtilis PE-11. AAPS PharmSciTech 4, 440–448 (2003). https://doi.org/10.1208/pt040456

3. Wery, N., Gerike, U., Sharman, A., Chaudhuri, J. B., Hough, D. W., & Danson, M. J. (2003). Use of a packed-column bioreactor for isolation of diverse protease-producing bacteria from antarctic soil. Applied and environmental microbiology, 69(3), 1457–1464. https://doi.org/10.1128/aem.69.3.1457-1464.2003

4. Rydén, A. C., Lindberg, M., & Philipson, L. (1973). Isolation and characterization of two protease-producing mutants from Staphylococcus aureus. Journal of bacteriology, 116(1), 25–32. https://doi.org/10.1128/JB.116.1.25-32.1973