Optimization of IgY inhibiting Porphyromonas gingivalis proliferation in oral simulation environment based on Box Behnken design response surface methodology

Abstract:

[Objective] Box Behnken design response surface methodology was used to optimize the colony count of IgY against Porphyromonas gingivalis in oral simulation environment in order to find the appropriate dose of IgY, initial density of P. gingivalis and culture time. [Methods] Final colony count was used as the evaluation index, on the basis of single factor tests. Box Behnken RSM was used with three factors such as number of colonies at different dose of IgY, initial density of P. gingivalis and culture time in the artificial saliva. The experiment was repeated three times under the optimal conditions to verify the accuracy of the model. [Results] The results of single factor test showed that IgY had the best effect on the reproduction of P. gingivalis by the dose of 180 mmol/L IgY, the initial amount of 2×106 CFU/mL P. gingivalis and the incubation at 37 °C for 4 h. The optimum culture conditions were as follows: dose of IgY was 165 mmol/L, the initial amount of P. gingivalis was 2×106 CFU/mL, culture time was 4.5 h. Under these conditions the final number of colonies was 5.92×105 CFU/mL. Compared with the predicted value of 5.85×105 CFU/mL, the relative error with the theoretical value was 1%. Analysis of Variance showed the P value of the model was significant, and the missing P value was not significant. The theoretical value was in good agreement with the measured value. [Conclusion] The number of colonies of P. gingivalis in the simulated oral environment was significantly decreased, which indicated that the regression model could be a good predictor of the response of P. gingivalis in the oral cavity.