Acidic conditions induce the accumulation of orange Monascus pigments during liquid-state fermentation of Monascus ruber M7

  • Li LiEmail author
  • Suo Chen
  • Mengxiang Gao
  • Baomiao Ding
  • Jialan Zhang
  • Youxiang Zhou
  • Yingbao Liu
  • Hualin Yang
  • Qinghua Wu
  • Fusheng ChenEmail author
Biotechnological products and process engineering


The influence of pH on the biosynthesis of orange Monascus pigments (OMPs) in Monascus ruber M7 was investigated. Under acidic fermentation conditions, pigment mixtures predominantly rich in OMPs were obtained. HPLC analysis revealed the presence of four orange components (O1O4) and four yellow components (Y1Y4) in the mixtures, and the dominant ones were O1 and O3, which accounted for 56.0% to 75.9% of the total pigments in the pH range 36. Subsequently, O1 and O3 were identified by LC-DAD-ESI/MS as Rubropunctatin and Monascorubrin, respectively. The yield of OMPs was observed to be inversely dependent on pH. At pH 3, large amounts of OMPs with high purity (79.1%) were accumulated. A real-time quantitative PCR analysis revealed that the expression of genes related to the biosynthesis of OMPs in M. ruber M7 was upregulated at acidic pH as compared to neutral pH, and the variation in the level of expression of these genes with pH was consistent with the production of OMPs. These results indicated that the large accumulation of OMPs under acidic condition involved the acidic pH-induced transcription of genes related to the biosynthesis of OMPs. These results would contribute towards the development of an efficient technology for large-scale production of OMPs.


Monascus ruber Orange Monascus pigments pH regulation Biosynthesis genes 


Funding information

This work was supported by the Programs of Natural Science Foundation of China (No. 31501453, 31730068 and 31701573), the Program of Science and Technology Department of Hubei Province (No. 2019AHB067), and the Yangtze Fund for Youth Teams of Science and Technology Innovation (No. 2016cqt02).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interests.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Supplementary material

253_2019_10114_MOESM1_ESM.pdf (216 kb)
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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.College of Life ScienceYangtze UniversityJingzhouChina
  2. 2.College of Animal ScienceYangtze UniversityJingzhouChina
  3. 3.Institute of Quality Standard and Testing Technology for Agro-ProductsHubei Academy of Agricultural SciencesWuhanChina
  4. 4.Key Laboratory of Environment Correlative DietologyHuazhong Agricultural UniversityWuhanChina
  5. 5.College of Food Science and TechnologyHuazhong Agricultural UniversityWuhanChina

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