1. Autotrophic adaptive laboratory evolution of the acetogen Clostridium autoethanogenum delivers the gas-fermenting strain LAbrini with superior growth, products, and robustness.
- Author
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Ingelman H, Heffernan JK, Harris A, Brown SD, Shaikh KM, Saqib AY, Pinheiro MJ, de Lima LA, Martinez KR, Gonzalez-Garcia RA, Hawkins G, Daleiden J, Tran L, Zeleznik H, Jensen RO, Reynoso V, Schindel H, Jänes J, Simpson SD, Köpke M, Marcellin E, and Valgepea K
- Subjects
- Bioreactors microbiology, Mutation, Autotrophic Processes, Directed Molecular Evolution, Gases metabolism, Clostridium metabolism, Clostridium genetics, Clostridium growth & development, Fermentation
- Abstract
Microbes able to convert gaseous one-carbon (C1) waste feedstocks are increasingly important to transition to the sustainable production of renewable chemicals and fuels. Acetogens are interesting biocatalysts since gas fermentation using Clostridium autoethanogenum has been commercialised. However, most acetogen strains need complex nutrients, display slow growth, and are not robust for bioreactor fermentations. In this work, we used three different and independent adaptive laboratory evolution (ALE) strategies to evolve the wild-type C. autoethanogenum to grow faster, without yeast extract and to be robust in operating continuous bioreactor cultures. Multiple evolved strains with improved phenotypes were isolated on minimal media with one strain, named "LAbrini", exhibiting superior performance regarding the maximum specific growth rate, product profile, and robustness in continuous cultures. Whole-genome sequencing of the evolved strains identified 25 mutations. Of particular interest are two genes that acquired seven different mutations across the three ALE strategies, potentially as a result of convergent evolution. Reverse genetic engineering of mutations in potentially sporulation-related genes CLAU_3129 (spo0A) and CLAU_1957 recovered all three superior features of our ALE strains through triggering significant proteomic rearrangements. This work provides a robust C. autoethanogenum strain "LAbrini" to accelerate phenotyping and genetic engineering and to better understand acetogen metabolism., Competing Interests: Declaration of Competing Interest We declare that LanzaTech has interest in commercial gas fermentation with C. autoethanogenum and Audrey Harris, Steven D. Brown, Grant Hawkins, Jim Daleiden, Loan Tran, Hunter Zeleznik, Rasmus O. Jensen, Vinicio Reynoso, Heidi Schindel, and Michael Köpke are employees of LanzaTech., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2024
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