Utilization of date syrup as a substrate for carotenoid production by Rhodotorula glutinis

The potential use of date syrup, for the production of carotenoids by Rhodotorula glutinis in batch fermentation process, was investigated during 7 days. The results revealed that carbon (glucose or date syrup) and nitrogen sources [yeast extract, (NH4)2SO4 and NH4NO3] had a significant influence on biomass and carotenoid production. Maximum yield of total carotenoid production (7.94 mg/L) with carotene content (2040 μg/g) and biomass (3.90 g/L) was obtained from R. glutinis after 7 days of fermentation in a substrate containing date syrup and yeast extract. The highest biomass (8.03 g/L) was obtained in the culture containing glucose and yeast extract, while the total carotenoid content of 6.72 mg/L with 836.86 μg/g carotene was produced in this medium. Significant differences were observed when comparing the average biomass and total carotenoid productions in different cultures and fermentation times. Our results demonstrated that date syrup (from low quality dates), as aby-product at a lower price, could be profitably used as a suitable carbon source for carotenoid production by R. glutinis.