Optimization of Ferment Condition of ε-Poly-L-Lysine by Response Surface Methodology

Abstract

Streptomyces albus Y07, a strain which could produce ε-Poly-L-lysine (ε-PL) had been screened in our previous study. The fermentation conditions for ε-Poly-L-lysine production were further optimized through response surface method in this work. A central composite design was adopted to study the effect of culture volume, shaking speed, initial culture pH, as well as inoculation amount on ε-PL production. A quadratic polynomial equation for ε-Poly-L-lysine production was obtained by multiple regression analysis. The equation was as follow: The accuracy and general availability of the polynomial model were proved to be adequate with R2 Pre = 0.8373. The optimized conditions were as follows: culture volumn: 50/500ml, culture pH = 7, inoculation amount: 10% of the total culture volume, shaking speed: 180rpm. Under the optimized conditions, the ε-PL production reached 1.085g / L. And the validity of the predicited model was further confirmed through verification experiments..