Optimization of β-Carotene Production from Rhodotorula glutinis ATCC 4054 Growing on Agro-industrial Substrate Using Plackett–Burman Design

Abstract

Beta-carotene, one of most widely known carotenoid molecules, is commercially used as food and feed additive, cosmetic and pharmaceutical products. The current study was aimed to evaluate the utilization of some agro-industrial wastes for β-carotene production by Rhodotorula glutinis yeast and optimization of the production process using Plackett–Burman design. Rice bran, sugarcane molasses and sugarcane bagasse were used in the production medium. Rice bran was the best low-cost substrate for biomass and β-carotene production of R. glutinis. Physical and nutritional parameters such as glucose, sucrose, yeast extract, NH₄Cl, NaCl, MgSO₄, KH₂PO₄, pH, inoculum size and agitation rate were screened using Plackett–Burman design to identify critical factors. Results of Plackett–Burman design suggest that sucrose, NaCl, KH₂PO₄ and pH were the most significant factors for β-carotene accumulation on rice bran. A quadratic model was constructed by response surface methodology—central composite design to study the impact of interaction and quadratic effect of these critical factors on β-carotene production. From predicted values obtained using quadratic equations, it was seen that the optimization to achieve maximum production of β-carotene was; sucrose 18.6 g/l, initial pH at 5.4, KH₂PO₄ 1.01 g/l, NaCl 0.66 g/l to achieve a β-carotene content from 1.23 mg/kg rice bran to 3.20 mg/kg. As far as HPLC analysis is concerned, it clearly proved the presence of β-carotene which had 68.2% purity as compared with standard.