Development of increased acetic acid tolerance in anaerobic homoacetogens through induced mutagenesis and continuous selection

Reed, William H.; Keller, Frederick A.; Kite, F.E.; Bogdan, M. E.; Ganoung, J.S.

doi:10.1016/0141-0229(87)90154-2

Cited by 18 publications

(10 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Classical evolution methods involving strain enrichment under selective pressure have been used with the goal of improving acetate tolerance in order to improve acetate production by Clostridium thermoaceticum (Reed et al 1987) and A. aceti (Steiner and Sauer 2003a). This technique has also been used to increase acetate tolerance of Zymomonas mobilis (Joachimsthal et al 1998) and E. coli (Steiner and Sauer 2003b;Fernández-Sandoval et al 2012).…”

Section: Other Bacteriamentioning

confidence: 98%

Adaptation and tolerance of bacteria against acetic acid

Trček

Mira

Jarboe

2015

Appl Microbiol Biotechnol

180

View full text Add to dashboard Cite

Acetic acid is a weak organic acid exerting a toxic effect to most microorganisms at concentrations as low as 0.5 wt%. This toxic effect results mostly from acetic acid dissociation inside microbial cells, causing a decrease of intracellular pH and metabolic disturbance by the anion, among other deleterious effects. These microbial inhibition mechanisms enable acetic acid to be used as a preservative, although its usefulness is limited by the emergence of highly tolerant spoilage strains. Several biotechnological processes are also inhibited by the accumulation of acetic acid in the growth medium including production of bioethanol from lignocellulosics, wine making, and microbe-based production of acetic acid itself. To design better preservation strategies based on acetic acid and to improve the robustness of industrial biotechnological processes limited by this acid's toxicity, it is essential to deepen the understanding of the underlying toxicity mechanisms. In this sense, adaptive responses that improve tolerance to acetic acid have been well studied in Escherichia coli and Saccharomyces cerevisiae. Strains highly tolerant to acetic acid, either isolated from natural environments or specifically engineered for this effect, represent a unique reservoir of information that could increase our understanding of acetic acid tolerance and contribute to the design of additional tolerance mechanisms. In this article, the mechanisms underlying the acetic acid tolerance exhibited by several bacterial strains are reviewed, with emphasis on the knowledge gathered in acetic acid bacteria and E. coli. A comparison of how these bacterial adaptive responses to acetic acid stress fit to those described in the yeast Saccharomyces cerevisiae is also performed. A systematic comparison of the similarities and dissimilarities of the ways by which different microbial systems surpass the deleterious effects of acetic acid toxicity has not been performed so far, although such exchange of knowledge can open the door to the design of novel approaches aiming the development of acetic acid-tolerant strains with increased industrial robustness in a synthetic biology perspective.

show abstract

Section: Other Bacteriamentioning

confidence: 98%

Adaptation and tolerance of bacteria against acetic acid

Trček

Mira

Jarboe

2015

Appl Microbiol Biotechnol

180

View full text Add to dashboard Cite

show abstract

“…However, this procedure is tedious and could take a long time to find a useful mutant. Reed et al (1987) developed a continuous selection process in a bioreactor environment incorporated with UV irradiation and a chemical mutagen, which killed most of cells in the bioreactor. In this work, acetate tolerant strains were obtained in the bioreactor without using mutagens.…”

Section: Acetate Tolerancementioning

confidence: 99%

Acetate production from whey lactose using co-immobilized cells of homolactic and homoacetic bacteria in a fibrous-bed bioreactor

Huang

Yang

1998

Biotechnol. Bioeng.

View full text Add to dashboard Cite

Acetate was produced from whey lactose in batch and fed‐batch fermentations using co‐immobilized cells of Clostridium formicoaceticum and Lactococcus lactis. The cells were immobilized in a spirally wound fibrous sheet packed in a 0.45‐L column reactor, with liquid circulated through a 5‐L stirred‐tank fermentor. Industrial‐grade nitrogen sources, including corn steep liquor, casein hydrolysate, and yeast hydrolysate, were studied as inexpensive nutrient supplements to whey permeate and acid whey. Supplementation with either 2.5% (v/v) corn steep liquor or 1.5 g/L casein hydrolysate was adequate for the cocultured fermentation. The overall acetic acid yield from lactose was 0.9 g/g, and the productivity was 0.25 g/(L h). Both lactate and acetate at high concentrations inhibited the homoacetic fermentation. To overcome these inhibitions, fed‐batch fermentations were used to keep lactate concentration low and to adapt cells to high‐concentration acetate. The final acetate concentration obtained in the fed‐batch fermentation was 75 g/L, which was the highest acetate concentration ever produced by C. formicoaceticum. Even at this high acetate concentration, the overall productivity was 0.18 g/(L h) based on the total medium volume and 1.23 g/(L h) based on the fibrous‐bed reactor volume. The cells isolated from the fibrous‐bed bioreactor at the end of this study were more tolerant to acetic acid than the original culture used to seed the bioreactor, indicating that adaptation and natural selection of acetate‐tolerant strains occurred. This cocultured fermentation process could be used to produce a low‐cost acetate deicer from whey permeate and acid whey. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 60: 498–507, 1998.

show abstract

“…UV mutagenesis was performed on Clostridium thermoaceticum and Clostridium thermoautophicum [18], whereas acetate-tolerant E. coli and S. cerevisiae mutants were generated through evolutionary engineering [11,19]. …”

Section: Introductionmentioning

confidence: 99%

Improving Acetate Tolerance of Escherichia coli by Rewiring Its Global Regulator cAMP Receptor Protein (CRP)

Chong

Yeow²,

Wang³

et al. 2013

PLoS ONE

View full text Add to dashboard Cite

The presence of acetate exceeding 5 g/L is a major concern during E. coli fermentation due to its inhibitory effect on cell growth, thereby limiting high-density cell culture and recombinant protein production. Hence, engineered E. coli strains with enhanced acetate tolerance would be valuable for these bioprocesses. In this work, the acetate tolerance of E. coli was much improved by rewiring its global regulator cAMP receptor protein (CRP), which is reported to regulate 444 genes. Error-prone PCR method was employed to modify crp and the mutagenesis libraries (~3×106) were subjected to M9 minimal medium supplemented with 5–10 g/L sodium acetate for selection. Mutant A2 (D138Y) was isolated and its growth rate in 15 g/L sodium acetate was found to be 0.083 h-1, much higher than that of the control (0.016 h-1). Real-time PCR analysis via OpenArray® system revealed that over 400 CRP-regulated genes were differentially expressed in A2 with or without acetate stress, including those involved in the TCA cycle, phosphotransferase system, etc. Eight genes were chosen for overexpression and the overexpression of uxaB was found to lead to E. coli acetate sensitivity.

show abstract

Development of increased acetic acid tolerance in anaerobic homoacetogens through induced mutagenesis and continuous selection

Cited by 18 publications

References 6 publications

Adaptation and tolerance of bacteria against acetic acid

Adaptation and tolerance of bacteria against acetic acid

Acetate production from whey lactose using co-immobilized cells of homolactic and homoacetic bacteria in a fibrous-bed bioreactor

Improving Acetate Tolerance of Escherichia coli by Rewiring Its Global Regulator cAMP Receptor Protein (CRP)

Contact Info

Product

Resources

About