Abstract:

To establish an electrotransformation method for Paenibacillus polymyxa strain JSa-9, the effects of different
factors on the transformation efficiency of strain JSa-9 by electroporation were explored by evaluating cell growth phase,
electric field intensity, electroporation buffer, plasmid DNA contentation and recovery time. The results showed that a
transformation efficiency of 0.12 × 103 CFU transformants per μg DNA was achieved when P. polymyxa JSa-9 cell culture
reached an OD595 nm of 0.3. Under the conditions of 17.5 kV/cm, 200 Ω and 25 μF for electric field strength, electric resistance
and capacitance, respectively, the electroporation efficiency was roughly 0.5 × 103 transformants per μg DNA when adding
1.0 μg/100 mL of plasmid DNA to an electroporation buffer containing 0.5 mol/L sorbitol, 0.5 mol/L mannitol, and 10%
glycerol and recovering for 17 h. Moreover, the transformation efficiency of P. polymyxa JSa-9 protoplasts was increased
to approximately 1.0 × 103 CFU transformants per μg DNA under electric field strength of 5.0 kV/cm upon addition of
0.8 μg/100 mL plasmid DNA.

Key words: Paenibacillus polymyxa JSa-9, electroporation, transformation efficiency