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Continuous succinic acid fermentation by Escherichia coli KJ122 with cell recycle

Paper ID Volume ID Publish Year Pages File Format Full-Text
34191 45010 2011 8 PDF Available
Title
Continuous succinic acid fermentation by Escherichia coli KJ122 with cell recycle
Abstract

•Productivity of 3 g L−1 h−1 and yield of 0.77 g g−1 achieved at D = 0.15 h−1.•Increased pyruvate dehydrogenase activity at higher D contributes to yield increase.•Minimal oxidative TCA/glyoxylate flux detected from analysis.•Batch results inferior in productivity but superior in yield and titre.

High cell densities were obtained by separating the cells with an external hollow fibre filter. Extreme product inhibition at high succinate titres resulted in cell death and subsequent lysis. Accordingly, the highest succinate titre obtained during continuous fermentation was 25 g L−1 at a dilution rate of 0.05 h−1. The highest volumetric productivity of 3 g L−1 h−1 and the highest succinate yield (0.77 g g−1) were obtained at the highest dilution rate (0.15 h−1). The improved yield was caused by increased pyruvate dehydrogenase activity, leading to a decrease in pyruvate and formate excretion and an increase in the reductive flux towards succinate as additional reduction power was produced. The oxidative tricarboxylic acid cycle flux was determined to be minimal, with most of the acetyl coenzyme A (acetyl-CoA) culminating as acetate. Although comparative batch fermentations exhibited a fivefold lower volumetric productivity than the maximum obtained in the cell recycle runs, higher succinate titres (56 g L−1) and yields (0.85 g L−1) were obtained. The higher batch yields were attributed to pyruvate and formate consumption after the termination of cell growth.

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Keywords
Succinic acid; E. coli; Continuous cell recycle; High-cell-density fermentation; Metabolic flux analysis
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Continuous succinic acid fermentation by Escherichia coli KJ122 with cell recycle
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 50, Issue 12, December 2015, Pages 2004–2011
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
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Full-text PDF Download
Online Support
Any Questions? feel free to contact us