Characteristics and transformation of Zymomonas mobilis with plasmid pKT230 by electroporation

Transformation of Zymomonas mobilis with plasmid pKT230 by electroporation was achieved with a transformation efficiency of 9.0?±?1.8?×?10³ per μg plasmid DNA. The growing state of the host cells before transformation, the RC time constant for pulsing at the optimal electric field strength (7.5?kV/cm), the plasmid concentration and the post-incubation time prior to outgrowth in RM medium were the sensitive factors influencing the efficiency of the transformation. The data from batch cultures revealed that the plasmid-harboring cells, Z. mobilis (pKT230), had the same growth pattern as plasmid-free cells. The yield factors of biomass production and ethanol formation by Z. mobilis were nearly unchanged after being transformed and grown in the selective medium where the gene for antibiotic resistance was expressed. The results suggested that the plasmid pKT230 was stable in Z. mobilis and qualified for being a cloning vector in the construction of a recombinant ethanol-producer.