ECOS™ Competent Cells

The fastest transforming cells worldwide-

1 minute transformation

With “ECOS™” standing for “EColi One-Step”, and its reverse “SOCE” standing for “SOC Eliminated”,  the name itself speaks for the advantages.
minute, 1 step high-efficiency transformation and no SOC recovery step required, truly a design to save your time.

Choose a strain

Don't know which strain to use? LOOK HERE!

Selection Guide for ECOS Competent Cells

Mutations and Respective Strains

With its high efficiency, it is suitable for cloning large plasmids and cDNA library construction, also allowing for blue-white screening

Use for:

  • Cloning / Subcloning
  • Scale-up application
  • Blue/white screening

Lack of Lon and Omp proteases allows for high-level protein expression


Use for:
  • IPTG induced gene expression of  toxic/non-toxic protein expression using T7-based vectors
  • Subcloning

The fastest growing strain; colonies show up about 8 hours. Also carries the F’episome, which allows for blue/white screening

Use for:

  • Urgent needs cloning needs
  • Preparation of ssDNA
  • Gene library construction
  • Subcloning

A Tetracycline resistant strain modified to be ideal for blue/white screening

Use for:

  • Blue/white screening
  • Cloning / Subcloning
  • cDNA library

A MC1061 derivative which is Streptomycin resistant and can prevent DNA methylation

Designed to propagate large inserts in DNA library cloning

Use for:

  • Genomic library cloning
  • Large inserts
  • Cloning of methylated cytosine or adenine containing DNA
  • Blue/white screening

Chloramphenicol resistant K12 strain deficient in both dam and dcm genesfor use with Dam or Dcm-sensitive restriction enzymes

Use for:

  • Plasmids free of Dam and Dcm methylations

BL21(DE3) Derived Strain with deficient of endA and recA and high efficiency of transformation

Use for:

  • The plasmid in Sonic can be extracted
  • Primary Cloning / Subcloning
  • Protein Expression with T7 promoter
Transformation Protocol

Special Tips

Patented Technology
Yeastern Biotech Co., Ltd. owns the patent of ECOS™ technology (protocol) exclusively in USA, UK, Taiwan, and France (Patent No. US 6,864,088; GB 2383582; I 229696; FR 2832727, etc.). Under the protection of this patent, Yeastern Biotech is the only company that has the right to use the protocol with the claims that transformation with our ECOS™ chemically competent cells can be finished within one minute and SOC is not needed. If anyone intends to sell competent cells that use ECOS™ protocol or its similar version, please contact our headquarters in Taiwan for licensing.
Quality Control
Each lot of competent cells has to pass three quality control tests before shipping:
  1. Efficiency test: each batch of ECOS™ should meet the claimed transformation efficiency at the time of production using Protocol 4 (Page 3-3) and supercoiled pUC19 DNA.
  2. Contamination test: competent cells were plated directly on ampicillin plates without being transformed. To pass the test, no colonies should be seen after overnight incubation.
  3. A-complementation test: this test is performed for all ECOS™ competent cells except for ECOS™ 21(DE3) and ECOS™ 2163. To pass the test, the ratio of white colonies over the total colonies should be less than 3%