CHARACTERISTICS AND TRANSFORMATION OF ZYMOMONAS-MOBILIS WITH PLASMID PKT230 BY ELECTROPORATION

Transformation of Zymomonas mobilis with plasmid pKT230 by electropora tion was achieved with a transformation efficiency of 9.0 +/- 1.8 x 10 (3) per mu g plasmid DNA. The growing state of the host cells before t ransformation, the RC time constant for pulsing at the optimal electri c field strength (7.5 kV/cm), the plasmid concentration and the post-i ncubation time prior to outgrowth in RM medium were the sensitive fact ors influencing the efficiency of the transformation. The data from ba tch cultures revealed that the plasmid-harboring cells, Z. mobilis (pK T230), had the same growth pattern as plasmid-free cells. The yield fa ctors of biomass production and ethanol formation by Z. mobilis were n early unchanged after being transformed and grown in the selective med ium where the gene for antibiotic resistance was expressed. The result s suggested that the plasmid pKT230 was stable in Z. mobilis and quali fied for being a cloning vector in the construction of a recombinant e thanol-producer.