Synthetic Biology:Media

Introduction
The wide variety of culture media used by different researchers makes it difficult to repeat experiments or to make the behavior of engineered biological systems reproducible. It would be desirable to develop or choose a culture medium that would work reliably for a wide range of experiments and devices.

There are some drawbacks to the culture media that are typically used today. For example, the casamino acids used to supplement M9 media are of variable composition and may contain trace amounts of lactose that can perturb experiments. Other media, have a high level of auto-fluorescence.

Here are some of the characteristics of an optimal standard culture media for bacteria -
 * Defined and standard constituents
 * Be able to support a relatively high level and rate of cell growth
 * Easy to produce
 * Low fluorescence
 * Stable over long periods of time.
 * Cheap

Note that these characteristics are in addition to other requirments for a growth media such as good buffering capacity.

Current status
Currently the only media that we have tried that appears to satisfy most of the above criteria is Neidhardt EZ Rich Defined. it can be purchased from Teknova. Priced at approximately $28/liter means that it is not especially cheap. Within the MIT Synthetic Biology Group, this media has proved quite successful.

Future Steps
It may make sense to define not just one, but multiple standard media that are suitable for a wider range of applications than any single media. One way to do this may be to pick a gold standard media, such as Neidhardt EZ Rich Defined and then define modifications to that. For example, we could choose a minimal media that is based on the Neidhardt rich media that would be cheaper and hence more suitable for large volume work such as chemostats. This could be selectively supplemented with some of the ingredients from the rich media to produce a small range of similar, defined media.