Fermentative production, comparative characterization with carrots, and functional analysis of β-carotene produced from Rhodotorulla toruloids

Abstract

Beta-carotene is the most widely demanded red-orange colored pigment having several applications in the food, cosmetic, and dying industries. Synthetic pigments pose serious side effects leading to the need for natural alternatives. In this study, β-carotene was extracted from fungi, and carrots. The confirmation and characterization of β-carotene was carried out via spectrophotometry, Thin Layer chromatography, and High-Performance Liquid Chromatography. Finally, the antimicrobial and antioxidant activities of the pigment were identified and its application as a dye was tested. The isolated yeast strain was identified as Rhodotorulla toruloids. Submerged fermentation of R. toruloids in YPD medium (wit 4% Dextrose) produced maximum biomass (0.6g/L) at 25°C. Using chloroform and methanol, 0.36g/L β-carotene yield was obtained. The R. toruloids extracted β-carotene showed the highest antibacterial potential against Salmonella sp. with 25.3±0.3 mm inhibition zones as compared to that of carrot extracted β-carotene i.e., 20.3±0.26mm. The DPPH analysis also revealed R. toruloids derived β-carotene as a strong antioxidant. The R. toruloids extracted β-carotene also cast a strong red color on cotton indicating it as a suitable candidate for organic dye. It is concluded from this study that β-carotene extracted from R. toruloids showed better antimicrobial and antioxidant potential along with its efficient ability to dye cotton as compared to the carrot's β-carotene. Hence, R. toruloids, being easily available and cost-effective production can prove better β-carotene source as compared to carrots.