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B. subtilis Secretory Protein Expression System

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Bacillus subtilis has become an increasingly popular host for recombinant protein expression. With its ability to secrete protein directly into culture media, amenability to medium- and large-scale fermentation, lack of codon bias, and designation by the U.S. Food and Drug Administration as an organism that is Generally Regarded As Safe (GRAS), it’s no wonder that the majority of industrially-produced enzymes are expressed in Bacillus species such as B. subtilis. Optimization of secretion, however, may be required to achieve optimal yield. To address this concern, the B. subtilis Secretory Protein Expression System from Takara Bio allows rapid development of a B. subtilis clone library, with each clone bearing a pBE-S construct in which the ORF of your protein of interest is fused with 173 different sequences for unique signal peptides. By performing a downstream assay to identify and select the clone that secretes the highest amount of functional protein, you can quickly identify which signal peptide results in the most efficient expression of your desired secreted protein.

Technical Data:


  • Includes pBE-S DNA, an E. coli/B. subtilis shuttle vector containing the B. subtilis-derived subtilisin (aprE) promoter, secretory signal peptide (aprE SP), multiple cloning site (MCS) and 3′ (C-terminal) His-tag sequence.
  • Supplied with SP DNA Mixture, a library of DNA sequences encoding 173 unique secretory signal peptides that can be inserted upstream of your target gene.
  • Fully compatible with In-Fusion cloning kits and systems, allowing rapid and easy construct generation.
  • Includes B. subtilis strain RIK1285


  • Optimize secretion by identifying the signal peptide which provides the highest level of expression of secreted protein.
  • The clone with the highest level of expression is then ready to use for scaled-up protein expression using B. subtilis.


SP DNA Mixture (0.032 pmol/µL) 45 µL
pBE-S DNA (0.5 µg/µL) 20 µg
B. subtilis RIK1285 (Glycerol Stock) 100 µL x 2


  • The B. subtilis Secretory Protein Expression System provides sufficient reagents for 10 library construction reactions.
  • Genotype of B. subtilis RIK1285:Marburg 168 derivative: trpC2, ys1, aprEdelta3, nprR2, nprE18


    SP DNA mixture and pBE-S DNA: –20°C

B. subtilis

     RIK1285 glycerol stock: –80°C

pBE-S Vector information

For vector map and vector sequence files, refer to the “Documents” tab.

Related In-Fusion Cloning products

For rapid and easy cloning, use the In-Fusion Cloning Systems or Kits. Products in the In-Fusion portfolio vary by geographic location; see the In-Fusion product pages from Clontechfor more information about products available in your region.

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