Multiple optimization and statistical evaluation of astaxanthin production utilizing olive pomace

• Olive pomace was utilized to produce astaxanthin pigment by the SSF with two experimental designs.
• Moisture content and inoculation rate were the optimal parameters for the SSF.
• High yields, 220.24±17.47 µg/gdp and 191.33±2.81 µg/gdp for ATCC 24,202 and ATCC 24,259, respectively were obtained.
• 81.12% antioxidant capacity of the produced astaxanthin was determined.
• Additional numerical analysis were applied to confirm the results of and modeling and optimization.

Solid State Fermentation (SSF) of olive pomace to astaxanthin pigment was accomplished within the frame of Box-Behnken and rotatable central composite experimental designs. Temperature, moisture content and pH for two astaxanthin producer yeasts, ATCC 24,202 (Xanthophyllomyces dendrorhous) and ATCC 24,259 (Sporidiobolus salmonicolor) were optimized at the first stage. 220.24±17.47 µg/gdp as maximum astaxanthin yield was obtained by ATCC 24,202 at 15.0 °C, 4.5 pH and 90.0% moisture content. Inoculation rate and incubation time factors of the second stage were optimized for yield and antioxidant capacity of the produced astaxanthin. Confirmation of the experimental and statistical evaluations concluded that astaxanthin production from olive pomace could be performed with a high efficient accurately.