Carotenoid Production by Rhodotorula sp. on Fruit Waste Extract As a Sole Carbon Source and Optimization of Key Parameters

Fruit waste extract was selected as the sole substrate for carotenoid production and the effect of parameters like pH, temperature and agitation have been studied. A two-step simple sequential strategy was employed for the optimization of carotenoid production by Rhodotorula rubra. In the first step, one factor at a time was employed to evaluate the impact of pH on carotenoid production. The outcome revealed that pH has noteworthy influence on pigment production at ambient conditions with constant temperature and agitation. The produced carotenoid was characterized and confirmed by UV-Visible and FT-IR spectroscopic analyses.A Box–Behnken design was then applied in the second step to optimize the pH, temperature and agitation to obtain high pigment yield. The statistical experimental design predicted the high yield conditions of different responses. The interaction between pH and temperature stood vital for improved carotenoid production (2.98 ± 0.28 mg/L) with biomass yield of 7.83 mg/mL by the optimization of significant parameters. The optimum conditions followed for high yield carotenoids are pH (7.0), temperature (28.2 °C), and agitation (150 rpm). Along with the above, biomass growth conditions were also studied and optimum parameter values were reported. The present work shows the effectiveness of abundantly available cheaper fruit waste extract as a sole substrate in obtaining carotenoids in significant amount by R. rubra.