Environmental research delivers valuable bacterial resources for biotechnology. We believe that systematic long-term preservation of bacteria will promote future biotechnological innovations, by safeguarding the accessibility of bacteria already recognized to have interesting features and providing a "pool" of bacterial resources for novel applied research. To this end, we want to advocate the incorporation of preservation tests in environmental or applied microbiological research. This paper introduces non-specialists to different preservation methods for bacteria. Several parameters that influence long-term storage of bacterial resources are explained and practical tips and guidelines are formulated. Also, the vital role of public culture collections is highlighted and the state-of-the-art of preservation of non-pure cultures is described.