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Selective enhancement of autotrophic acetate production with genetically modified Acetobacterium woodii

Paper ID Volume ID Publish Year Pages File Format Full-Text
23236 43422 2014 6 PDF Available
Title
Selective enhancement of autotrophic acetate production with genetically modified Acetobacterium woodii
Abstract

•We are able to transform the acetogenic bacterium, Acetobacterium woodii, with different plasmids.•The overexpression of different genes of the Wood–Ljungdahl pathway resulted in an increased acetate production of A. woodii.•Grown on CO2/H2, the recombinant A. woodii strains produced more acetate compared to a control strain.•Grown autotrophically under optimized conditions on CO2/H2, A. woodii pJIR750_THF was identified as best acetate producer with a maximum of about 51 g L−1 acetate in 3.8 days.

Great interest has emerged in the recent past towards the potential of autotrophic acetogenic bacteria for the sustainable production of fuels and chemicals. This group of microorganisms possesses an ancient pathway for the fixation of carbon dioxide in the presence of hydrogen, making them highly attractive for the utilization of gas mixtures as a cheap and abundant carbon and energy source. As more and more genome sequence data of acetogens becomes available, the genetic tools are being developed concomitantly. Here, we demonstrate for the first time the genetic modification of the well-characterized acetogen Acetobacterium woodii. This microorganism selectively produces acetate under autotrophic conditions, but seems to be limited at high acetate concentrations. To increase the carbon flow through the Wood–Ljungdahl pathway and therefore increase the efficiency of CO2 fixation, genes of enzyme groups of this pathway were selectively overexpressed (the four THF-dependent enzymes for the processing of formate as well as phosphotransacetylase and acetate kinase to enhance an ATP-generation step). Acetate production with genetically modified strains was increased in a batch process under pH-controlled reaction conditions in a stirred-tank reactor with continuous sparging of H2 and CO2. Final acetate concentrations of more than 50 g L−1 acetate were thus measured with the recombinant strains at low cell concentrations of 1.5–2 g L−1 dry cell mass in less than four days under autotrophic conditions.

Keywords
Acetate; Acetobacterium woodii; Autotrophic; Genetic modification; CO2 + H2
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Selective enhancement of autotrophic acetate production with genetically modified Acetobacterium woodii
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 178, 20 May 2014, Pages 67–72
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us