Mohammad Reza Nasri Nasrabadi, Seyed Hadi Razavi
Abstract
The present work investigated on carotenogenesis with high β-carotene content by a new isolated high-activity strain-producer Rhodotorula acheniorum mutant MRN in cheese whey ultrafiltrate. After a serial of UV, ethymethanesurfonate (EMS), and nitrosoguanidine (NTG) mutagenesis, a mutant named MRN of the red lactose-positive yeast strain R. acheniorum was obtained. Then, the effects of different growth medium factors on carotenoid production by this mutant at batch-scale level were identified and optimized by means of response surface methodology (RSM) in order to achieve high-level production of β-carotene. The optimum conditions required to achieve the highest level of β-carotene (262.12±1.01 mg/L) were determined as follows: whey ultrafiltrate (WU) lactose concentration 55 g/L, pH 5.85, ammonium sulfate concentration 3.5 g/L, temperature 23°C, and aeration rate 1.56 vvm. The medium optimization resulted in a 6.45-fold increase in volumetric production (262.12±1.01 mg/L) and a 4.62-fold increase in the cellular accumulation (10.69±0.19 mg/g) of β-carotene.
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Keywords: Rhodotorula acheniorum,whey ultrafiltrate,β-carotene,mutagenesis,response surface methodology.
