Optimization of culture medium and scale-up production of astaxanthin using corn steep liquor as substrate by response surface methodology

Abstract

Astaxanthin is a natural carotenoid with strong antioxidant activity. In this paper, the effects of carbon source, corn steep liquor, distiller grains, and initial pH on the growth and astaxanthin production of Phaffia rhodozyma D3 were evaluated. The optimal medium composition was 32 g/L glucose, 12 g/L corn steep liquor as nitrogen source, and the initial pH was 6.7. Phaffia rhodozyma D3 was cultured in a shake flask under these optimized conditions, the biomass was 6.47 g/L, the astaxanthin/OD₄₇₅ was 15.16, and the astaxanthin content was 1.41 mg/g. The astaxanthin content was further increased to 4.70 mg/g by the combination of TiO₂ stimulation and the expanding cultivation of P. rhodozyma D3 in a 5 L fermenter, which was 2.81 times that of the control group. Expanding fermentation implies the possibility of large-scale production in the astaxanthin industry. Corn steep liquor was used as an alternative nitrogen source to culture P. rhodozyma D3, which could both reduce the production cost of astaxanthin and increased the by-products utilization rate.

Keywords:

• Astaxanthin
• culture medium optimization
• industrial by-products
• Phaffia rhodozyma

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The Changchun Science and Technology Development Plan Project (21ZGN33), the China Agriculture Research System of MOF and MARA, the National Grain Industry Leading Talent Program of China (LL2018201), and Sangon Biotech (Shanghai) Co. Ltd. provided financial and technical support for this study.