Production of astaxanthin pigment from cereal and legume wastes by solid state fermentation and techno-economic analysis by simulation

In this thesis, it was aimed to produce astaxanthin pigment from wheat, rice and lentil wastes by applying solid state fermentation with Yamadazyma guilliermondii ATCC 90197, Yarrowia lipolytica ATCC 24060, Xanthophyllomyces dendrorhous ATCC 24202 and Sporidiobolus salmonicolor ATCC 24259 yeasts. Box-Behnken experimental design matrix consisting 17 runs was created with temperature, pH and moisture content parameters for each waste and yeast fermentation system. The experimental results were modeled and optimized to obtain the highest astaxanthin amount by using response surface methodology. Maximum astaxanthin yield as 109.23 μg astaxanthin/g dry waste with a 96.71 % antioxidant capacity was produced using wheat bran with X. dendrorhous at the temperature of 20 °C, pH of 3.5 and 90 % of moisture content. The results of the optimum fermentation conditions were verified by the experimental and statistical analyses. Kinetic study was performed for the optimum system by the measurements of product formation, substrate consumption and microbial growth parameters. The yield coefficients in batch systems were calculated to determine the productivity. A plant design for the optimum system by using SuperPro Designer simulation program was proposed and economic parameters were analyzed. For the base case, the total capital investment for the plant was estimated at $22,308,000. The payback period of astaxanthin production was calculated as 4.92 years. The capacity of 4,799.91 kg/batch was calculated as the break-even point for the astaxanthin production. Economic evaluations demonstrated that the process was a feasible alternative to produce astaxanthin from wheat bran by using X. dendrorhous.