We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Comparison of engineered Escherichia coli AF1000 and BL21 strains for (R)-3-hydroxybutyrate production in fed-batch cultivation.
- Authors
Perez-Zabaleta, Mariel; Guevara-Martínez, Mónica; Gustavsson, Martin; Quillaguamán, Jorge; Larsson, Gen; van Maris, Antonius J. A.
- Abstract
Accumulation of acetate is a limiting factor in recombinant production of (R)-3-hydroxybutyrate (3HB) by Escherichia coli in high-cell-density processes. To alleviate this limitation, this study investigated two approaches: (i) deletion of phosphotransacetylase (pta), pyruvate oxidase (poxB), and/or the isocitrate lyase regulator (iclR), known to decrease acetate formation, on bioreactor cultivations designed to achieve high 3HB concentrations. (ii) Screening of different E. coli strain backgrounds (B, BL21, W, BW25113, MG1655, W3110, and AF1000) for their potential as low acetate-forming, 3HB-producing platforms. Deletion of pta and pta-poxB in the AF1000 strain background was to some extent successful in decreasing acetate formation, but also dramatically increased excretion of pyruvate and did not result in increased 3HB production in high-cell-density fed-batch cultivations. Screening of the different E. coli strains confirmed BL21 as a low acetate-forming background. Despite low 3HB titers in low-cell-density screening, 3HB-producing BL21 produced five times less acetic acid per mole of 3HB, which translated into a 2.3-fold increase in the final 3HB titer and a 3-fold higher volumetric 3HB productivity over 3HB-producing AF1000 strains in nitrogen-limited fed-batch cultivations. Consequently, the BL21 strain achieved the hitherto highest described volumetric productivity of 3HB (1.52 g L−1 h−1) and the highest 3HB concentration (16.3 g L−1) achieved by recombinant E. coli. Screening solely for 3HB titers in low-cell-density batch cultivations would not have identified the potential of this strain, reaffirming the importance of screening with the final production conditions in mind.
- Subjects
ESCHERICHIA coli; ACETATES; ACETIC acid; FACTORS of production; TITERS
- Publication
Applied Microbiology & Biotechnology, 2019, Vol 103, Issue 14, p5627
- ISSN
0175-7598
- Publication type
Article
- DOI
10.1007/s00253-019-09876-y