BL21(DE3) bacteria are convenient for protein expression using the T7 promoter. The (DE3) designation indicates that the host is a lysogen of lambda prophage (DE3), and therefore carries a chromosomal copy of the T7 RNA polymerase gene under control of the lacUV5 promoter (inducible by addition of IPTG or using the Staby^TMSwitch auto-inducible medium). BL21(DE3) is the most widely used host for protein expression because it is deficient in the Lon and OmpT proteases.

Standard E. coli BL21(DE3) bacteria are offered in the 24, 48 and 96 formats, so you can pick the one that best suits the needs of your experiment. The competent E. coli BL21(DE3) bacteria are consistently high quality, with high efficiency: > 8x10⁷ bact/µg DNA (higher than that of competitors). The competent bacteria come complete with SOC medium. Each tube contains 100µl of competent E. coli BL21(DE3), which is sufficient for one high efficiency transformation.
High-efficiency competent E. coli BL21(DE3) are supplied in a 96-tube tray. This convenient format gives you the freedom to perform from 1 to 96 transformations at a time, without thawing more tubes of cells than needed. You can remove individual tubes by cutting cap strips. Thus, this format eliminates the reduced efficiencies that occur as a result of repeated freezing and thawing and makes possible high-throughput transformation. Racks feature 8 x 12 holes pattern for rapid processing using multi-channel pipettors. Alpha-numeric, non-reversing, rack and lid ensure positive sample ID.

BL21(DE3) bacteria are compatible with the Staby^TMSwitch auto-inducible medium (without IPTG).

BL21(DE3) genotype : F^- ompT lon hsdS_B (r_B^-m_B^-) gal dcm (DE3)

Benefits:

• Freedom to use anywhere from 1-96 reactions
• No wasted reactions
• High efficiency (≥ 8.10⁷ cfu/µg DNA)
• Economical pricing
• High-level protein expression