The only way to be sure about the correct incubation period is to do a trial run and sample periodically. For example, perform a plaque assay on hourly samples to get the phage titre, and plot on a graph to show the trend.

Factors other than time are also of importance (e.g. growth phase, cell density, aeration, culture medium, etc.).

See chapters: Practical Methods for Determining Phage Growth Parameters and Phage Production and Maintenance of Stocks, Including Expected Stock Lifetimes pp 175 to 219 In Bacteriophages: Methods and Protocols, Volume 1: Isolation, Characterization, and Interactions

Editors: Clokie, Martha R. J., Kropinski, Andrew (Eds.)

Vincent Mulholland Thank you for your advice, I will do as you adviced in small scale trial :)

Sincerely, Jinsun Lee

Carlos G Leon-Velarde Thank you for your help :) I will look at the book you recommended.

sincerely, Jinsun Lee

Phage cultivation takes two days:

* Day1: infection of TG1 cells (E.Coli) at exponential phase with Phages at a MOI of about 20 (this process takes 20 mn to 30 min) without shaking. the pellet of infected bacterial cells is resuspended in medium contained the phage resistance gene and cultivated O/N.

*Day2: phages (in the supernatent) are precipitated in ice with PEG/NaCl solution for at least 30mn. after centrifugation, phage pellet is resuspended in PBS and quantified to estimate the number of new phage particles.