Direct production of astaxanthin from food waste by Phaffia rhodozyma.

[Display omitted] • Food waste (FW) could be used as complete medium for astaxanthin fermentation. • The different fermentation strategies of astaxanthin from FW were compared. • Mechanism of astaxanthin production in the direct fermentation were investigated. • FW showed potential for low-cost industrial production of astaxanthin. Bioconversion of food waste (FW) into value-added products is a promising approach to solve FW management problem and achieve the global goal of carbon peak and carbon neutralization. In this study, FW could be used as a complete medium to compare the effects of four different fermentation strategies on direct astaxanthin fermentation by Phaffia rhodozyma. The carotenoid production by direct fermentation (DF) reached 129.5 mg/L, increasing by 61.3 %, compared with separate hydrolysis and fermentation (SHF), and carotenoid production by simultaneous saccharification fermentation (SSF) and 1 h pre-hydrolysis SSF (PSSF) were only 20.2 % and 21.5 % higher than DF, respectively. The mechanism of astaxanthin production in the DF could be attributed to the utilization of rice starch due to the production of amylase, and the stimulation of cell growth resulted from the metal elements and the lipid of soybean oil in FW. Remarkably, a 70.3 % increase of carotenoid production was observed when substrate loading increased from 10 % to 20 %. The present study provides a novel process for astaxanthin production from direct bioconversion of FW by P. rhodozyma , which shows potential for low-cost industrial production of astaxanthin. [ABSTRACT FROM AUTHOR]