Hello, 

Please can you suggest me a method to preserve microorganisms (gram-negative bacteria and green microalgae) up to 5-6 months prior counting them in a flow cytometer? I know PFA is the best fixative, but I would like to know if there is any alternative, less toxic and less laborious method than PFA fixation, which allows long-term storage and does not disturb the FC analysis.

Thank you in advance

Kind regards