Using the Plackett-Burman design in optimization of culturalparameters of probiotic Lacticaseibacillus casei isolated from dairyproducts

Background and Aim : Probiotics are live bacteria with valuable properties on human health.These bacteria or their by-products are used as preservatives in many products. TheLacticaseibacillus casei is one of the well-known bacteria in the probiotic industry. One of themost important and primary steps in probiotic manufacturing is optimizing biomass production.The mathematical and statistical models, such as the Plackett-Burman and the central compositeexperimental design, are suitable methods for recognizing the importance of various factors inindustrial design and optimization.Methods : Twenty-five samples of local dairy products from rural areas in Tehran province werecollected. One of the best strains in terms of biomass production was L. casei, which identified bybiochemical tests and selected due to its probiotic properties such as acid resistance, bile resistance,lethal effect on pathogens, etc. The strain was confirmed by ۱۶S rRNA molecular exam. Theinfluence of various parameters, such as mineral elements, nitrogen and carbon sources, and initialpH of culture media was experimented by Plackett-Burman model and optimization processcarried out via the central composite experimental design.Results : The first-order mathematical model based on Plackett-Burman design indicated thatdextrose, primary pH, meat extract, sodium pyruvate, and ammonium citrate significantlyinfluenced on biomass production of the examined L.casei. The modified quadratic polynomialregression confirmed that maximum biomass production could be achieved by using of dextrose(۱۳.۲۵ g/l), primary pH (۵.۶), meat extract (۳.۸۶ g/l), sodium pyruvate (۲.۹۴ g/l), and ammoniumcitrate (۱.۵۵ g/l).Conclusion : This optimization process can be useful for the industrial production of the localstrain of L.casei in the industry of probiotic supplements.

Keywords:

Lacticaseibacillus casei , Probiotic , Dairy products