A new type of cryoprotective agents that are useful for retaining the viability and metabolic activity of frozen or freeze-dried microbial cultures, is disclosed. The cryoprotective agent comprises compounds involved in biosynthesis of nucleic acids. Methods for the preparation as well as the uses of such cultures are given. Such cultures are useful as starter cultures in the manufacturing of food and feed products. Starter cultures of the invention include culture of lactic acid bacteria, e.g. Lactococcus species as well as other species.