Temperature-induced expression of phb genes in Escherichia coli and the effect of temperature patterns on the production of poly-3-hydroxybutyrate

The plasmid pNDTM2 was constructed to contain the p(R)-p(L) promoter and th e phbC, A, and B genes which code for PHB synthase, beta -ketothiolase, and acetoacetyl-CoA reductase, respectively. This plasmid was transformed into Escherichia coli XL1-Blue. The effect of several thermal induction pattern s on the production of poly-3-hydroxybutyric acid (PHB) was investigated ba sed on fermenter experiments. Based on the experimental results with differ ent induction patterns, it was found that the temperature should be control led at 34 degreesC during the initial 10 h of cultivation to promote cell g rowth, and then it should be increased to 40 degreesC for induction. Then t he temperature should be lowered to 37 degreesC after 5 h to relieve the ef fect of the heat shock.