Maintenance of the anaerobic beer spoilage bacteria Pectinatus and Megasphaera

The preservation of Pectinatus and Megasphaera strains by freeze-drying and freezing, using different working methods and protective agents, was studied.Pectinatus strains isolated from beer, and all theMegasphaera strains, recovered well after freeze-drying and after freezing in reducing conditions. However, the recovery ofPectinatus strains isolated from yeast cultures was, in most of the conditions tested, very low, and after 2 years storage, they were almost non-viable. The only satisfactory method for these strains was rapid freezing in liquid nitrogen using 5% DMSO as protective agent.