Construction of Trehalose Synthetic Recombinant Lactobacillus paracasei Strain and Its Stress Tolerance Evaluation

Objective:Constructed expression vector which contained the OtsBA gene of Escherichia coli,and recombinated new strains.The endogenous synthesized trehalose of recombinant strains were analyzed with the purpose of the protective effects among multiple stress.Method:The gene of OtsBA was cloned into pMG76e vector,and expressed in Lactobacillus paracasei L14 with Bio-Rad Gene Pulsor.The recombinant protein and the stress tolerance was detected.Result:The new expression vector was constructed successfully.The recombinant protein was no difference.The viability of recombinant strains under heat stress was increased by 62-fold compared with wild-type strain after 10 minutes.The H2O2 stress tolerance in 15 minutes was improved 3-fold.And osmotic stress tolerance increased by 1-fold.The acid stress tolerance did not improved significantly.The viability of logarithmic phase recombinant strains survival after the freeze-drying was 3 higher than that.Conclusion:The endogenous synthesized trehalose of recombinant strains has protective effects with multiple stress as a whole.