The resuscitation of Viable But Non-Culturable (VBNC) state in Escherichia coli DH5α as one of the most usable
expression host was investigated. The VBNC state in bacteria is defined as while the cells are alive but unable to
grow visibly on nonselective growth medium. After collecting several samples, Non-culturable E. coli DH5α (that
has undertaken on various recombinant manipulations) were divided into different groups in order to carry-out
different experiments. They were treated to heat shock at 42ºC in different periods of time, different concentration of
Bile-salts and NaCl and combinational of these methods. The results showed that the almost of resuscitation
treatment had positive effect on reactivation of VBNC E. coli DH5α. The combination of these parameters (various
NaCl and bile salts concentration and heat shock method at 42 °C in different time) in a binary manner, also
inferred to suitable results. Furthermore, by applying the three stresses simultaneously we achieved optical density
up to 0.58 and 9×108 CFU/ml which had presented the best results. The results show that by applying some
alterations in the condition of such recombinant E. coli DH5α, the growth path of these bacteria which remain to a
VBNC phase can be changed to the normal status