Journal of Industrial Microbiology & Biotechnology

, Volume 40, Issue 12, pp 1423–1432

Improvement of cell growth and l-lysine production by genetically modified Corynebacterium glutamicum during growth on molasses

  • Jianzhong Xu
  • Junlan Zhang
  • Yanfeng Guo
  • Yugui Zai
  • Weiguo Zhang
Fermentation, Cell Culture and Bioengineering

DOI: 10.1007/s10295-013-1329-8

Cite this article as:
Xu, J., Zhang, J., Guo, Y. et al. J Ind Microbiol Biotechnol (2013) 40: 1423. doi:10.1007/s10295-013-1329-8

Abstract

Fructose-1,6-bisphosphatase (FBPase) and fructokinase (ScrK) have important roles in regenerating glucose-6-phosphate in the pentose phosphate pathway (PPP), and thus increasing l-lysine production. This article focuses on the development of l-lysine high-producing strains by heterologous expression of FBPase gene fbp and ScrK gene scrK in C. glutamicum lysCfbr with molasses as the sole carbon source. Heterologous expression of fbp and scrK lead to a decrease of residual sugar in fermentation broth, and heterologous expression of scrK prevents the fructose efflux. Heterologous expression of fbp and scrK not only increases significantly the activity of corresponding enzymes but also improves cell growth during growth on molasses. FBPase activities are increased tenfold by heterologous expression of fbp, whereas the FBPase activity is only increase fourfold during co-expression of scrK and fbp. Compared with glucose, the DCW of heterologous expression strains are higher on molasses except co-expression of fbp and scrK strain. In addition, heterologous expression of fbp and scrK can strongly increase the l-lysine production with molasses as the sole carbon source. The highest increase (88.4 %) was observed for C. glutamicum lysCfbr pDXW-8-fbp-scrK, but the increase was also significant for C. glutamicum lysCfbr pDXW-8-fbp (47.2 %) and C. glutamicum lysCfbr pDXW-8-scrK (36.8 %). By-products, such as glycerol and dihydroxyacetone, are decreased by heterologous expression of fbp and scrK, whereas trehalose is only slightly increased. The strategy for enhancing l-lysine production by regeneration of glucose-6-phosphate in PPP may provide a reference to enhance the production of other amino acids during growth on molasses or starch.

Keywords

l-Lysine production Heterologous expression Fructose-1,6-bisphosphatase Fructokinase Molasses 

Copyright information

© Society for Industrial Microbiology and Biotechnology 2013

Authors and Affiliations

  • Jianzhong Xu
    • 1
  • Junlan Zhang
    • 2
  • Yanfeng Guo
    • 1
  • Yugui Zai
    • 1
  • Weiguo Zhang
    • 1
  1. 1.The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of BiotechnologyJiangnan UniversityWuXiPeople’s Republic of China
  2. 2.OriGene Biotechnology Co., LtdWuXiPeople’s Republic of China

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