Optimization of Single Cell Protein Production by Candida utilis Using Juice Extracted from Pineapple Waste through Response Surface Methodology

Response surface methodology was applied to optimize protein content in Candida utilis grown in pineapple waste medium. A three-level full factorial design was used to develop a quantitative interpretation of mathematical models between the two variables studied, inoculum size 2.0-10.0% (v/v) and total soluble solids in medium (1 -5 Brix) at 30 h fermentation time. Yeast cells were harvested, ruptured mechanically and the soluble extract was freeze-dried for determination of protein, vitamin-B, 5'-ribonucleotide and total sugar content. Maximum protein content in the yeast 66.61% (w/w) was obtained from the predicted optimum inoculum size of 7.83% (v/v) and Brix level of 3.02 . Highest level of biomass, vitamin-B, 5'-ribonucleotide and total sugar content within the experimental region increased 216.8%, 17.5%, 38.0% and 60.8% respectively after optimization. A verification experiment, conducted at optimized protein content conditions produced values that were close to the predicted values, indicating the reliability of the model used.