title: Application of a mathematical model and Differential Evolution algorithm approach to optimization of bacteriocin production by Lactococcus lactis C7.
abstract: The effect of pH and temperature on cell growth and bacteriocin production in Lactococcus lactis C7 was investigated in order to optimize the production of bacteriocin. The study showed that the bacteriocin production was growth-associated, but declined after reaching the maximum titer. The decrease of bacteriocin was caused by a cell-bound protease. Maximum bacteriocin titer was obtained at pH 5.5 and at 22 degrees C. In order to obtain a global optimized solution for production of bacteriocin, the optimal temperature for bacteriocin production was further studied. Mathematical models were developed for cell growth, substrate consumption, lactic acid production and bacteriocin production. A Differential Evolution algorithm was used both to estimate the model parameters from the experimental data and to compute a temperature profile for maximizing the final bacteriocin titer and bacteriocin productivity. This simulation showed that maximum bacteriocin production was obtained at the optimal temperature profile, starting at 30 degrees C and terminating at 22 degrees C, which was validated by experiment. This temperature profile yielded 20% higher maximum bacteriocin productivity than that obtained at a constant temperature of 22 degrees C, although the total amount of bacteriocin obtained was slightly decreased.
authors.affiliation: Department of Mathematics, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand. tumath@gmail.com
authors.forename: Sompop
authors.initials: S
authors.lastname: Moonchai
authors.forename: Weeranuch
authors.initials: W
authors.lastname: Madlhoo
authors.forename: Kanidtha
authors.initials: K
authors.lastname: Jariyachavalit
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
authors.forename: Suteaki
authors.initials: S
authors.lastname: Shioya
authors.forename: Somchai
authors.initials: S
authors.lastname: Chauvatcharin
mesh_terms: D000465:Algorithms; D001430:Bacteriocins / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D003198:Computer Simulation; D005246:Feedback / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D013294:Lactococcus lactis / Q000378:metabolism*; D008954:Models, Biological; D011786:Quality Control; D013696:Temperature
chemical_list: D001430:Bacteriocins