Hi Horacio, you can find help in the following article: Hummel, W. and Kula, MR. 1989; Simple method for small scale disruption of bacteria and yeasts. J. Microbiol. Meth. 9, 201-209 If you have further problems, you can contact me via email: riebel at ibt022.ibt.kfa-juelich.de, good luck Bettina Riebel --