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Microb Cell Fact. 2019 Jan 9;18(1):4. doi: 10.1186/s12934-018-1051-3.

Improvement of isoprene production in Escherichia coli by rational optimization of RBSs and key enzymes screening.

Author information

1
Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.135 Songlin Road, Qingdao, 266101, People's Republic of China.
2
University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
3
Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.135 Songlin Road, Qingdao, 266101, People's Republic of China. zhanghb@qibebt.ac.cn.
4
Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.135 Songlin Road, Qingdao, 266101, People's Republic of China. nianrui@qibebt.ac.cn.
5
Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.135 Songlin Road, Qingdao, 266101, People's Republic of China. xianmo1@qibebt.ac.cn.

Abstract

BACKGROUND:

As an essential platform chemical mostly used for rubber synthesis, isoprene is produced in industry through chemical methods, derived from petroleum. As an alternative, bio-production of isoprene has attracted much attention in recent years. Previous researches were mostly focused on key enzymes to improve isoprene production. In this research, besides screening of key enzymes, we also paid attention to expression intensity of non-key enzymes.

RESULTS:

Firstly, screening of key enzymes, IDI, MK and IspS, from other organisms and then RBS optimization of the key enzymes were carried out. The strain utilized IDIsa was firstly detected to produce more isoprene than other IDIs. IDIsa expression was improved after RBS modification, leading to 1610-fold increase of isoprene production. Secondly, RBS sequence optimization was performed to reduce translation initiation rate value of non-key enzymes, ERG19 and MvaE. Decreased ERG19 and MvaE expression and increased isoprene production were detected. The final strain showed 2.6-fold increase in isoprene production relative to the original strain. Furthermore, for the first time, increased key enzyme expression and decreased non-key enzyme expression after RBS sequence optimization were obviously detected through SDS-PAGE analysis.

CONCLUSIONS:

This study prove that desired enzyme expression and increased isoprene production were obtained after RBS sequence optimization. RBS optimization of genes could be a powerful strategy for metabolic engineering of strain. Moreover, to increase the production of engineered strain, attention should not only be focused on the key enzymes, but also on the non-key enzymes.

KEYWORDS:

Enzyme screening; Isoprene; Metabolic engineering; RBS sequence optimization; T.I.R.

PMID:
30626394
PMCID:
PMC6327615
DOI:
10.1186/s12934-018-1051-3
[Indexed for MEDLINE]
Free PMC Article

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