Valorization of shalgam juice plant waste for the production of carotenoids by Rhodotorula glutinis

Authors : Abdulkadir KESKİN, Melis FIRAT, Ayşe Ezgi ÜNLÜ BÜYÜKTOPCU

Pages : 79-87

Doi:10.31015/jaefs.2023.1.9

View : 10 | Download : 7

Publication Date : 2023-03-27

Article Type : Research Paper

Abstract :Food waste is an emerging global problem that should not be underestimated. One of the most abundant wastes in Türkiye and neighbour countries is the waste of shalgam juice plants insert ignore into journalissuearticles values(WSJP);. In this study, WSJP was used as a growth medium for Rhodotorula glutinis. The effects of initial medium pH insert ignore into journalissuearticles values(3.4-5.4);, carbon insert ignore into journalissuearticles values(0-60 g/L glycerol); and nitrogen sources insert ignore into journalissuearticles values(0-1 g/L urea); were investigated on biomass, medium pH, reducing sugar concentration, total lipid and carotenoid contents, as well as carotenoid composition insert ignore into journalissuearticles values(torulene, torularhodin, β-carotene);. When crude waste extract insert ignore into journalissuearticles values(no additional nutrient); was used as growth medium insert ignore into journalissuearticles values(initial medium pH 3.4, 6.14 g/L sugar);, biomass was relatively low insert ignore into journalissuearticles values(1.47±0.055 g/L);, due to acidic pH and insufficient nutrients. However, these stress conditions increased the production of total lipid and carotenoid contents by R. glutinis. The highest lipid and carotenoid contents were obtained as 0.14±0.0004 g/g dry cell weight insert ignore into journalissuearticles values(dcw); and 1221.57±0.59 µg/g dcw, respectively, under these circumstances. As additional stress factor fermentation medium -crude WSJP extract- was illuminated for 72 h. This increased lipid content by 1.7-fold, while showing low impact on carotenoid content. Interestingly, illumination changed the carotenoid composition by decreasing torulene and β-carotene percentages, but increasing torularhodin percentage. On the other hand, tuning the initial pH to an ambient value insert ignore into journalissuearticles values(5.4); and the addition of carbon and nitrogen sources stimulated cell growth insert ignore into journalissuearticles values(4.67±0.07 g/L);. This study presents the first time use of WSJP extract as a growth medium, without any additional nutrition, moreover, the simultaneous production of high-value added carotenoids.  
Keywords : Rhodotorula glutinis, waste, shalgam juice, lipid, carotenoid