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Cloning Competent Cell Strains

Ensure successful transformations with NEB competent E. coli for cloning. Choose from several high efficiency competent cell strains in a variety of formats that deliver performance, convenience and value.

  • High transformation efficiencies
  • Compatible with NEBuilder® HiFi DNA Assembly and Gibson Assembly® reactions, as well as ligation reactions. No dilution required!
  • Strains also available for cloning of toxic genes
  • All strains are free of animal products and are T1 phage resistant
  • Outgrowth medium and control plasmid are included
  • Choose from a variety of convenient formats, including single use tubes
  • Bulk formats and custom packaging are available
  • Take advantage of value pricing and no dry ice charges

Competent Cell Selection Guide

Product NEB # Characteristics Efficiency
NEB® 5-alpha Competent E. coli (High Efficiency) C2987U
  • Versatile cloning strain
  • DH5α™ derivative
1 - 3 x 109 cfu/μg,
For C2987R: 1 - 5 x 108 cfu/μg
NEB® 10-beta Competent E. coli (High Efficiency) C3019I
  • Large plasmid and BAC cloning
  • DH10B™ derivative
1-3 x 109 cfu/µg
For C3019P: 1 - 3 x 108 cfu/µg
NEB® Stable Competent E. coli (High Efficiency) C3040I
  • High quality plasmid preparations due to endA mutation
  • Rapid growth recA strain
  • T1 phage resistance (fhuA)
  • Value pricing
  • Free of animal products
1-3 x 109 cfu/µg
NEB® Turbo Competent E. coli (High Efficiency) C2984I
  • Fastest growth – colonies visible after 6.5 hours
  • Plasmid preparation after 4 hours
1-3 x 109 cfu/µg
dam-/dcm- Competent E. coli C2925I
  • Dam/Dcm methyltransferase free plasmid growth
1-3 x 106 cfu/µg
NEB® 5-alpha F'Iq Competent E. coli (High Efficiency) C2992I
  • Toxic gene cloning
  • F´ strain with extremely high transformation efficiency
1-3 x 109 cfu/µg


NEB Competent E. coli Sampler

Try all four cloning strains in our NEB Competent E. coli Sampler


To help select the best strain for your experiment, please use NEBcloner®, our Cloning Competent Cell Selection Chart.

Competent Cell Formats

Formats NEB # Single-use 200 µl tubes 96-well plate Electrocompetent Subcloning Outgrowth Medium & Control Plasmid Included
NEB 5-alpha C2987
NEB 10-beta C3019
NEB Stable C3040  

NEB Turbo C2984  

dam-/dcm- C2925  

NEB 5-alpha F'Iq C2992    

Choose Type:

FAQs for Cloning Competent Cell Strains
Protocols for Cloning Competent Cell Strains
Advantages of NEB Competent Cells
  • Free of animal products 
  • T1 phage resistance (fhuA2) 
  • Media and control plasmid included with most strains 
  • A variety of convenient formats, including single use transformation tubes and, on request, 96 well plates 
  • Bulk sales capabilities with custom packaging
Advantages of NEB Cloning Strains
  • High transformation efficiencies 
  • EndA deficient for high quality plasmid preparation 
  • T1 phage resistant 
  • RecA deficient for reduced recombination of cloned DNA 
  • Free of animal products 
  • Suitable for blue/white screening 
  • Available as single-use tubes or multiple use aliquots 
  • Outgrowth media and control plasmid included 
  • Bulk sales capabilities with custom packaging formats
High Transformation Efficiencies with NEB Competent E. coli

Transformation efficiencies were compared using manufacturers’ recommended protocols. Values shown are the average of triplicate experiments.
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This product is intended for research purposes only. This product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.