Optimization of Carotenoid Production by Rhodosporidium babjevae and Evaluation of Antifungal and Dyeing Activity

Abstract

The aim of this study was to evaluate the antifungal, dyeing activity and optimization of carotenoid production by Rhodosporidium babjevae. Rhodosporidium red yeast is one of the natural alternative sources of carotenoids. Carotenoids are produced by a wide variety of bacteria, algae, fungi, and plants. These pigments serve a vital function as antioxidant protectors and have lately caught a lot of attention because of their positive impact on human health In this experimental-laboratory study, Rhodosporidium was isolated from different environmental sources in Isfahan. After carotenoid extraction based on the Davis method from Rhodosporidium, cell biomass, and the total amount of carotenoids were measured, and the carotenoid light absorption spectrum was determined. To optimize carotenoid production, one-factor and Taguchi methods evaluated incubation time factors, pH, nitrogen, and carbon source. Then, yeast carotenoid antifungal activity, minimum inhibitory concentration (MIC),and minimum fungicidal concentration (MFC) were determined. The stability of dye against washing, rubbing, and light was investigated to evaluate the carotenoid dyeing activity. In this experimental-laboratory study, Rhodosporidiums were isolated from different environmental sources in Isfahan. After carotenoid extraction according to Davis method from Rhodosporidiums, cell biomass, total amount of carotenoids was measured, and carotenoid light absorption spectrum was determined. To optimize carotenoid production, incubation time factors, pH, nitrogen and carbon source were evaluated by one-factor and Taguchi methods. Then, yeast carotenoid antifungal activity, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined. The stability of the dye against washing, rubbing and light was investigated to evaluate the carotenoid dyeing activity obtained. The optimum condition for carotenoid production was 96 hours of incubation, 2 g L-1 peptone, pH 5.5, and 30 g L-1 glucose. The optimal conditions of Taguchi were performed, and production of 11.67 mg L-1 was obtained. The carotenoid pigment isolated from Rhodosporidium babjevae showed no anti-candida properties but has antifungal activity against A. flavus and A. niger. Woolen fabric had washing fastness of 2 and cotton fabric had a washing fastness of 3. The staining grade on woolen and cotton fabrics was 4. The grade of color fastness of woolen and cotton fabrics against dry rubbing was 5, while the grade of color fastness against wet rubbing was 2 and 4, respectively. The optimum condition for carotenoids production was 96 hours’ time of incubation, 2g/l peptone, pH 5.5, and 30 g/l glucose. The optimal conditions of Taguchi were performed and a production of 11.67 μg / L was obtained. The carotenoid pigment isolated from Rhodosporidium babjevae showed no anti-candida properties. The color fastness was 4 for wool and 2 for cotton. The degree of washing stability was 2 for woolen fabric and 3 for cotton. The degree of staining on woolen and cotton fabrics was 4. The degree of color stability against dry rubbing of woolen and cotton fabric was 5 and the degree of color stability against wet rubbing of woolen and cotton fabric was 2 and 4, respectively. Based on the results, Rhodosporidium babjevae carotenoid is a suitable option for dyeing woolen and cotton fabrics with antifungal properties that can be used in industry. It is hoped that it can be used for the commercial production of carotenoids.