Droplet-Microfluidic-Based Promoter Engineering and Expression Fine-Tuning for Improved Erythromycin Production in Saccharopolyspora erythraea NRRL 23338

Kaiyue Yun; Yue Zhang; Shixin Li; Yan Wang; Ran Tu; Hao Liu; Meng Wang

doi:10.3389/fbioe.2022.864977

Droplet-Microfluidic-Based Promoter Engineering and Expression Fine-Tuning for Improved Erythromycin Production in Saccharopolyspora erythraea NRRL 23338

Front Bioeng Biotechnol. 2022 Apr 4:10:864977. doi: 10.3389/fbioe.2022.864977. eCollection 2022.

Authors

Kaiyue Yun^{1

2

3}, Yue Zhang^{2

3}, Shixin Li^{1

2

3}, Yan Wang^{1

2

3}, Ran Tu^{2

3}, Hao Liu¹, Meng Wang^{2

3}

Affiliations

¹ College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China.
² Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
³ Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.

Abstract

Erythromycin is a clinically important drug produced by the rare actinomycete Saccharopolyspora erythraea. In the wide-type erythromycin producer S. erythraea NRRL 23338, there is a lack of systematical method for promoter engineering as well as a well-characterized promoter panel for comprehensive metabolic engineering. Here we demonstrated a systematical promoter acquiring process including promoter characterization, engineering and high-throughput screening by the droplet-microfluidic based platform in S. erythraea NRRL 23338, and rapidly obtained a panel of promoters with 21.5-fold strength variation for expression fine-tuning in the native host. By comparative qRT-PCR of S. erythraea NRRL 23338 and a high-producing strain S0, potential limiting enzymes were identified and overexpressed individually using two screened synthetic promoters. As a result, erythromycin production in the native host was improved by as high as 137.24 folds by combinational gene overexpression. This work enriches the accessible regulatory elements in the important erythromycin-producing strain S. erythraea NRRL 23338, and also provides a rapid and systematic research paradigm of promoter engineering and expression fine-tuning in the similar filamentous actinomycete hosts.

Keywords: Saccharopolyspora erythraea; droplet-based microfluidics; erythromycin; gene overexpression; high-throughput screening; production improvement; promoter engineering.