Question

You are attempting to isolate and grow an organism from the ocean. Suggest a medium and incubation conditions that would be ideal for this organism. Explain your answer.

Answer 1

The potential for using marine microbes for biodiscovery is severely limited by the lack of laboratory cultures. It is a long‐standing observation that standard microbiological techniques only isolate a very small proportion of the wide diversity of microbes that are known in natural environments from DNA sequences.

A number of explanations are reviewed. The process of establishing laboratory cultures may destroy any cell‐to‐cell communication that occurs between organisms in the natural environment and that are vital for growth. Bacteria probably grow as consortia in the sea and reliance on other bacteria for essential nutrients and substrates is not possible with standard microbiological approaches.

Many useful bacteria can still be isolated using variations of plating techniques. Results are summarized for a study to culture bacteria from a long‐term observatory station in the English Channel.

It is worth considering the fundamental principles that microbiologists use in trying to establish cultures. The aim is to separate a single viable cell from other bacteria that are present in an assemblage and to maintain that physical separation while the cell divides to form a culture. This separation is traditionally done on agar plates or by dilution to extinction in liquid cultures.