DETECTING OPTIMUM AND COST-EFFICIENT OF MICROBIAL GROWTH RATE AND LACTOSE CONSUMPTION OF KLUYVEROMYCES LACTIS Y-8279 USING RSM

Exploring optimum and cost-efficient medium composition for microbial growth rate and lactose consumption of Kluyveromyces Lactis Y-8279 yeast culture growing on whey was studied by applying a multi-step response surface methodology (RSM). RSM is a combination of Plackett Burman (PB), Steepest-Ascent (SA) and Central Composite Design (CCD) Medium temperature, pH, yeast extract and lactose concentrations were evaluated the most effective operational factors through seven factors by applying PBD. These four factors were selected for SA program and SA experiments were carried out to find approximately maximum microbial concentration with lactose, pH, yeast extract and medium temperature. Then CCD was carried out with these factors (lactose, medium temperature, pH and yeast extract). Based on ANOVA test the optimum operational conditions of maximum growth rate were obtained as 18.8 g/L, 0.94 g/L, 5.2 and 27 degrees C, lactose concentration, yeast extract concentration, pH, and medium temperature, respectively. And then optimum operational conditions of lactose consumption were obtained as 13 g/L, 0.91 g/L, 8 and 27.5 degrees C, lactose concentration, yeast extract concentration, pH, and medium temperature, respectively too.