Effect of Acetic Acid on Ethanol Fermentation by Engineered Escherichia coli SZ470

2013 ◽  
Vol 724-725 ◽  
pp. 369-372
Author(s):  
Jin Hua Wang ◽  
Feng Huang ◽  
Xiao Zhao ◽  
Jin Fang Zhao ◽  
Yong Ze Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Acetic Acid ◽  
Specific Growth Rate ◽  
Ethanol Fermentation ◽  
Specific Growth ◽  
Ethanol Yield ◽  
Fermentation Medium ◽  
Minor Amount ◽  
Exponential Growth Phase

Hydrolysis of the aquatic vegetables waste would lead to the generation of some toxic components and by-products, such as weak acids, aldehydes and phenols. They might do harm to sequent fermentation process to some extent. The toxic effect of acetic acid on ethanol fermentation by ethanologenic Escherichia coli SZ470 was investigated. The growth curves of Escherichia coli SZ470, specific growth rate (μ), the ethanol yield and consumption of glucose were compared with different concentrations of acetic acid addition in the fermentation medium. When concentrations of acetic acid exceed 0.8 g/L, the exponential growth phase of Escherichia coli SZ470 was significantly expanded from 10 h to above 12 h, moreover, the ethanol yield and consumption of glucose drastically decreased. Specific growth rate increased as acetic acid concentrations below 0.6 g/L, but fell as acetic acid concentrations exceeded 0.6 g/L, the result indicated that minor amount of acetic acid might be helpful with growth of Escherichia coli SZ470.

Effect of specific growth rate on the production of a recombinant nuclease by Escherichia coli

2003 ◽  
Vol 14 (2) ◽  
pp. 101-107 ◽  
Author(s):  
Li-Chun Cheng ◽  
Lien-I Hor ◽  
Jau-Yann Wu ◽  
Teh-Liang Chen
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth

Influence of specific growth rate over the secretory expression of recombinant potato carboxypeptidase inhibitor in fed-batch cultures of Escherichia coli

2010 ◽  
Vol 45 (8) ◽  
pp. 1334-1341 ◽  
Author(s):  
Juan-Miguel Puertas ◽  
Jordi Ruiz ◽  
Mónica Rodríguez de la Vega ◽  
Julia Lorenzo ◽  
Glòria Caminal ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Fed Batch ◽  
Secretory Expression ◽  
Batch Cultures ◽  
Carboxypeptidase Inhibitor

Evolution of Escherichia coli During Growth in a Constant Environment

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 349-358
Author(s):  
Robert B Helling ◽  
Christopher N Vargas ◽  
Julian Adams
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Continuous Culture ◽  
Specific Growth ◽  
Maximum Specific Growth Rate ◽  
Constant Environment ◽  
Single Clone ◽  
Mixed Populations

ABSTRACT Populations of Escherichia coli, initiated with a single clone and maintained for long periods in glucose-limited continuous culture, developed extensive polymorphisms. In one population, examined after 765 generations, two majority and two minority types were identified. Stable mixed populations were reestablished from the isolated strains. Factors involved in the development of this polymorphism included differences in the maximum specific growth rate and in the transport of glucose, and excretion of metabolites by some clones which were utilized by minority clones.

scholarly journals NUTRIENT MEDIUM SELECTION AND OPTIMIZATION OF AVIBACTERIUM PARAGALLINARUM DEEP CULTURE METHOD

2019 ◽  
pp. 12-16
Author(s):  
M. S. Firsova ◽  
V. A. Yevgrafova ◽  
A. V. Potekhin
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Growth Phase ◽  
Nutrient Medium ◽  
Specific Growth ◽  
Exponential Phase ◽  
Exponential Growth Phase ◽  
Lag Phase ◽  
Optimal Method ◽  
Avibacterium Paragallinarum

Different liquid nutrient media supplemented with growth factors intended for Avibacterium paragallinarum strain No. 5111 cultivation were com­pared. The highest specific growth rate (μ = 0.787 ± 0.041 h-1) and the maximal accumulation of the agent’s biomass (Х = 9.52 ± 0.04 lg CFU/ cm3) were reported when cultured in casein soybean broth. Herewith, the mean time of the live microbial cell concentration doubling was minimal (td = 0.88 h), and the exponential growth phase lasted for 6 hours. The optimal method for Avibacterium paragallinarum cultivation in casein soy­bean broth in laboratory bioreactor Biotron LiFlus GX was determined through the measurements and adjustment of basic physical and chemical parameters. The time period until the culture reached the stationary growth phase was maximal with aeration at 1.0 l/min; herewith, the O2 partial pressure in the nutrient medium did not exceed 25%. The period of the intense decrease of medium’s pH was accompanied with the exponential phase of the bacterial growth. The nutrient medium’s pH ranging from 7.30 ± 0.02 to 7.90 ± 0.06 had no significant impact on the specific growth rate of the strain and the lag phase duration was minimal – 0.36–0.45 h. The strain cultivation in the nutrient medium with pH 7.90 ± 0.06 demonstrated maximal aggregation of the bacteria (9.76 ± 0.04 lg CFU/cm3). 40% glucose solution added at 0.6-0.8 g/l during cultivation facilitated the decrease of the suspension’s pH. Minimal redox value (–75 mV) was indicative of the completion of the exponential phase of the strain growth.  

scholarly journals Poly(3-Hydroxybutyrate) Synthesis by Recombinant Escherichia coli arcA Mutants in Microaerobiosis

2006 ◽  
Vol 72 (4) ◽  
pp. 2614-2620 ◽  
Author(s):  
Pablo I. Nikel ◽  
M. Julia Pettinari ◽  
Miguel A. Galvagno ◽  
Beatriz S. Méndez
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Deletion Mutant ◽  
Specific Growth ◽  
Dry Weight ◽  
Low Oxygen ◽  
Oxygen Conditions ◽  
In The Wild ◽  
Microaerobic Conditions

ABSTRACT We assessed the effects of different arcA mutations on poly(3-hydroxybutyrate) (PHB) synthesis in recombinant Escherichia coli strains carrying the pha synthesis genes from Azotobacter sp. strain FA8. The arcA mutations used were an internal deletion and the arcA2 allele, a leaky mutation for some of the characteristics of the Arc phenotype which confers high respiratory capacity. PHB synthesis was not detected in the wild-type strain in shaken flask cultures under low-oxygen conditions, while ArcA mutants gave rise to polymer accumulation of up to 24% of their cell dry weight. When grown under microaerobic conditions in a bioreactor, the arcA deletion mutant reached a PHB content of 27% ± 2%. Under the same conditions, higher biomass and PHB concentrations were observed for the strain bearing the arcA2 allele, resulting in a PHB content of 35% ± 3%. This strain grew in a simple medium at a specific growth rate of 0.69 ± 0.07 h−1, whereas the deletion mutant needed several nutritional additives and showed a specific growth rate of 0.56 ± 0.06 h−1. The results presented here suggest that arcA mutations could play a role in heterologous PHB synthesis in microaerobiosis.

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