FOOD SCIENCE ›› 2012, Vol. 33 ›› Issue (23): 244-248.

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Mutation Breeding of High-Yield Carotenoid Producing Rhodotorula mucilaginosa by N+ Implantation and Optimization of Solid-state Fermentation Conditions for Carotenoid Production

  

  • Received:2011-09-14 Revised:2012-11-02 Online:2012-12-15 Published:2012-12-12

Abstract: Rhodotorula mucilaginosa RM-1 was mutagenized by means of N+ implantation to obtain high-yield carotenoid producing mutants. The optimum dose of 10 keV N+ implantation was 2.0 × 1014 ion/cm2 and the best mutant (RM-21) revealed a 60.85% increase in carotenoid production when compared with the original strain. This mutant remained stable after the 10th passage and thus could be used for industrial production. Further investigations were conducted to optimize solid-state fermentation conditions for the production of carotenoid from corn flour and rice by mutant RM-21. The optimum fermentation conditions were determined as follows: a 3:1 (m/m) mixture of corn flour and rice with 75% added water as fermentation substrate, 4.0 g/L of glucose concentration, 2.5 g/L of NH4NO3 concentration, initial pH 6.0 and 10% of inoculum size. The fermentation time was 96 h and consisted of two stages: the fermentation temperature was 33 ℃ in the first 84 h and 28 ℃ in the following 12 h. Under these conditions, the yield of carotenoid was 7.04 μg/g dry matter, which revealed a 20.96% increase compared with constant temperature fermentation.

Key words: N+ implantation, carotenoid, Rhodotorula mucilaginosa, solid-state fermentation, temperature-shift culture

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