Improved Production of Tryptophan in Genetically Engineered Escherichia coli with TktA and PpsA Overexpression

Table 3

Stability of plasmids pSV709 and pMEL03 in TRTH1013 after 40 h of fermentation.

Plasmids	Stability with tetracycline and chloramphenicol (%)	Stability without antibiotics (%)
pSV709	100±2.3	98±2.5
pMEL03	85±7.1	86±4.4
pSV709 and pMEL03	84±6.2	83±4.5

Values show the ratio in percentage of colonies on agar plates with antibiotics to colonies on agar plates without antibiotics. Means are determined from at least three independent experiments.