LB Broth media formulations have been industry standards for the cultivation of Escherichia coli since the 1950’s (1,2,3). These media have been widely used in molecular microbiology applications for the preparation of plasmid DNA and recombinant proteins (4,5). The media are nutrient-rich formulations which provide peptides and peptones, vitamins, and trace elements. The three formulations (Lennox, Miller and Luria) differ in the amount of sodium chloride, thus providing selection of the appropriate osmotic conditions for the particular bacterial strain and desired culture conditions. The low salt formulations, Lennox and Luria, are ideal for cultures requiring salt-sensitive antibiotics such as Zeocin™.

pEX™ Protein Expression Media P9102-40 Media Optimization Kit™ P9102-40A Turbo Broth™ P9102-40B Superior Broth™ P9102-40C Power Broth™ P9102-40D Hyper Broth™ P9102-40E M9Y (Glucose) Broth™ P9102-40F Glucose-Nutrient Mix P9102-40G LB Broth (Miller)

Not sure which media expression system to choose? United States Biological has developed a unique research tool for protein expression media selection: Media Optimization Kit™

Our experiences with the expression of recombinant proteins have shown that the level of expression is very much dependent on the medium used. Some proteins are expressed well in one medium, but are not expressed in the same host strain in another medium or protein may be expressed in one medium while another protein is not expressed in the same medium.

This demonstrates why for each recombinant protein a medium screen becomes a crucial part of the optimization process. To facilitate the researchers’ efforts to develop the best systems for their proteins, we have developed a Media Optimization Kit.™. The kit is composed of six media formulations (including four that are unique and proprietary) which we have found over the years to be the most reliable for the increased production of recombinant proteins in Escherichia coli. The kit is used to quickly and easily identify the most suitable medium for the expression of a particular recombinant protein. Included are suggested approaches for improving the production of recombinant proteins, thus passing along the knowledge our staff scientists have acquired while working to produce a wide variety of proteins.

Terrific Broth is a richer media that would be suitable if higher cell densities and higher yields for plasmids or protein purifications are necessary. T2810: Terrific Broth (Powder) T2810-05: Terrific Broth, Complete with Carbon Source (Powder) T2810-10: Terrific Broth, Modified for Genomics (Powder) T2810-11: Terrific Broth, Modified for Fermentation, non-animal (Powder)

L1500: LB Agar Lennox (Powder) L1505: LB Broth Lennox (Powder) L1510: LB Top Agar Lennox (Powder) P9102-40H: Protein Expression Media, LB Broth Lennox (Powder) pEX™ P9102-40H1: Protein Expression Media, LB Broth Lennox (Liquid) pEX™

L1515: LB Agar Miller (Powder) L1520: LB Broth Miller (Powder) L1525: LB Top Agar Miller (Powder) P9102-40G: Protein Expression Media, LB Broth Miller (Powder) pEX™ P9102-40G1: Protein Expression Media, LB Broth Miller (Liquid) pEX™

L1530: L-Broth (Luria Broth) (Powder)