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ORIGINAL RESEARCH article

Front. Bioeng. Biotechnol.
Sec. Synthetic Biology
Volume 12 - 2024 | doi: 10.3389/fbioe.2024.1470830
This article is part of the Research Topic Recent advancements in microfluidic droplet platform for high-throughput single-cell analysis View all articles

SERS-based microdroplet platform for high-throughput screening of E. coli strains for the efficient biosynthesis of D-Phenyllactic acid

Provisionally accepted
Lin Hu Lin Hu Ruoshi Luo # Ruoshi Luo # Dan Wang Dan Wang *Fanzhen Lin Fanzhen Lin Kaixing Xiao Kaixing Xiao Yaqi Kang Yaqi Kang
  • Chongqing University, Chongqing, China

The final, formatted version of the article will be published soon.

    D-Phenyllactic acid (D-PLA) is a potent antimicrobial typically synthesized through chemical methods. However, due to the complexity and large pollution of these reactions, a simpler and more eco-friendly approach was needed. In this study, a strain for D-PLA biosynthesis was constructed, but the efficiency was restricted by the activity of D-lactate dehydrogenase (DLDH). To address this issue, a DLDH mutant library was constructed and the Surface-Enhanced Raman Spectroscopy (SERS) was employed for the precise quantification of D-PLA at the single-cell level. The TB24 mutant exhibited a significant improvement in D-PLA productivity and a 23.03-fold increase in enzymatic activity, which was attributed to the enhanced hydrogen bonding and increased hydrophobicity within the substrate-binding pocket. By implementing multi-level optimization strategies, including the co-expression of glycerol dehydrogenase (GlyDH) with DLDH, chassis cell replacement, and RBS engineering, a significant increase in D-PLA yields was achieved, reaching 128.4 g/L. This study underscores the effectiveness of SERS-based microdroplet high-throughput screening (HTS) in identifying superior mutant enzymes and offers a strategy for large-scale D-PLA biotransformation.

    Keywords: D-phenyllactic acid, surface-enhanced Raman spectroscopy, Microdroplet Screening, Directed Evolution, molecular docking

    Received: 26 Jul 2024; Accepted: 09 Sep 2024.

    Copyright: © 2024 Hu, Luo #, Wang, Lin, Xiao and Kang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Dan Wang, Chongqing University, Chongqing, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.