A simple preservation method for the short-medium term storage of environmental bacteria

A novel method is described for the short to medium term storage of environmental bacteria up to six months. Fifty environmental bacteria were employed in this study, which had been previously isolated from green spaces. These organisms comprised of 14 genera (10 Gram negative and 4 Gram positive) [Arthrobacter, Bacillus, Buttiauxella, Carnobacterium, Citrobacter, Enterobacter, Lelliottia, Pectobacterium, Pseudomonas, Rahnella, Serratia, Sporosarcina, Stenotrophomonas, Yersinia] and 16 identified species. Organisms were inoculated onto fresh plates of Standard Plate Count (SPC) agar and incubated aerobically at 30 °C for 72 h. Following this, plates with growth were stacked in metal plate racks and wrapped in plastic with a large autoclave bag and sealed with a cable tie. Plates were stored at 5 °C in the dark for six months, after which they were removed and the colonies checked for viability. All isolates were able to be recovered through passaging onto fresh SPC plates. This method is simple, inexpensive, versatile and widely adaptable and requires minimum preparation/handling/processing, utilising a small laboratory footprint for refrigerator space. Adoption and employment of this simple storage system encourages the routine archiving of environmental isolates for future research purposes.