SOB is a nutrient-rich bacterial broth designed to support the transformation and recovery of competent E. coli cells. SOC is a modified version of SOB that includes glucose to enhance cell recovery and provides an optimal carbon source while suppressing the expression of toxic genes carried on plasmids under the control of the lac promoter.

SOB and SOC media are nutrient-rich and contain tryptone, yeast extract, salts, and divalent magnesium ions to support healthy E. coli outgrowth following plasmid transformation after heat shock or electroporation. SOC includes all SOB components plus glucose, which provides extra energy to help cells recover rapidly. Using SOB and SOC media for recovery results in higher transformation efficiency and better survival than with standard growth media, like LB.

With our ready-to-use SOB and SOC liquid media, no preparation or sterilization steps are needed. To help save you time and resources and ensure you get reliable results, we offer production-ready formulations in a variety of convenient container formats to meet your specific needs. We also conduct rigorous quality testing and top-spread testing to ensure the sterility of our products and high consistency across batches.

If you ever do need to prepare SOB and SOC media yourself, dissolve the yeast extract, tryptone (or soytone for animal-free preparations), sodium chloride, and potassium chloride in water, autoclave the solution, then, after cooling, aseptically add magnesium salts (and glucose, for SOC). Please note that when you make your own media, you may see variations from batch to batch that could impact the replicability of your results.

We recommend storing our liquid SOB and SOC media at room temperature. Under these conditions, the shelf life can reach 730 days.