Biofilm monitoring: a perfect solution in search of a problem

2003 ◽  
Vol 47 (5) ◽  
pp. 9-18 ◽  
Author(s):  
Z. Lewandowski ◽  
H. Beyenal
Keyword(s):  
Consumption Rate ◽  
Glucose Consumption ◽  
Data Interpretation ◽  
Integrated System ◽  
Glucose Consumption Rate ◽  
Biofilm Heterogeneity

The main problem with monitoring biofilms is data interpretation. Biofilm heterogeneity causes monitored parameters to vary from location to location in the same biofilm, and it is difficult to assess to what extent these variations are caused by biofilm heterogeneity and to what extent they reflect other properties of the biofilm. We have used the concept of discretized biofilms, which is an integrated system of biofilm monitoring and data interpretation, to assess the effect of biofilm heterogeneity on biofilm activity. Using this approach we have estimated that a heterogeneous biofilm can be ten times more active, in terms of glucose consumption rate, than a homogeneous biofilm of the same thickness but with uniformly distributed density.

scholarly journals Influence of static magnetic fields on S. cerevisae biomass growth

2007 ◽  
Vol 50 (3) ◽  
pp. 515-520 ◽  
Author(s):  
João B. Muniz ◽  
Milton Marcelino ◽  
Mauricio da Motta ◽  
Alexandre Schuler ◽  
Mauricy Alves da Motta
Keyword(s):  
Magnetic Fields ◽  
Consumption Rate ◽  
Cylindrical Tube ◽  
Glucose Consumption ◽  
Dry Weight ◽  
Biomass Growth ◽  
Glucose Consumption Rate ◽  
Static Magnetic Fields ◽  
Tube Reactor ◽  
Flow Intensity

Biomass growth of Saccharomyces cerevisiae DAUFPE-1012 was studied in eight batch fermentations exposed to steady magnetic fields (SMF) running at 23ºC (± 1ºC), for 24 h in a double cylindrical tube reactor with synchronic agitation. For every batch, one tube was exposed to 220mT flow intensity SMF, produced by NdFeB rod magnets attached diametrically opposed (N to S) magnets on one tube. In the other tube, without magnets, the fermentation occurred in the same conditions. The biomass growth in culture (yeast extract + glucose 2%) was monitored by spectrometry to obtain the absorbance and later, the corresponding cell dry weight. The culture glucose concentration was monitored every two hours so as the pH, which was maintained between 4 and 5. As a result, the biomass (g/L) increment was 2.5 times greater in magnetized cultures (n=8) as compared with SMF non-exposed cultures (n=8). The differential (SMF-control) biomass growth rate (135%) was slightly higher than the glucose consumption rate (130 %) leading to increased biomass production of the magnetized cells.

scholarly journals Overflow Metabolism in Escherichia coli during Steady-State Growth: Transcriptional Regulation and Effect of the Redox Ratio

2006 ◽  
Vol 72 (5) ◽  
pp. 3653-3661 ◽  
Author(s):  
G. N. Vemuri ◽  
E. Altman ◽  
D. P. Sangurdekar ◽  
A. B. Khodursky ◽  
M. A. Eiteman
Keyword(s):  
Escherichia Coli ◽  
Consumption Rate ◽  
Nadh Oxidase ◽  
Glucose Consumption ◽  
Tca Cycle ◽  
Overflow Metabolism ◽  
Glucose Consumption Rate ◽  
Redox Ratio ◽  
E Coli ◽  
Acetate Formation

ABSTRACT Overflow metabolism in the form of aerobic acetate excretion by Escherichia coli is an important physiological characteristic of this common industrial microorganism. Although acetate formation occurs under conditions of high glucose consumption, the genetic mechanisms that trigger this phenomenon are not clearly understood. We report on the role of the NADH/NAD ratio (redox ratio) in overflow metabolism. We modulated the redox ratio in E. coli through the expression of Streptococcus pneumoniae (water-forming) NADH oxidase. Using steady-state chemostat cultures, we demonstrated a strong correlation between acetate formation and this redox ratio. We furthermore completed genome-wide transcription analyses of a control E. coli strain and an E. coli strain overexpressing NADH oxidase. The transcription results showed that in the control strain, several genes involved in the tricarboxylic acid (TCA) cycle and respiration were repressed as the glucose consumption rate increased. Moreover, the relative repression of these genes was alleviated by expression of NADH oxidase and the resulting reduced redox ratio. Analysis of a promoter binding site upstream of the genes which correlated with redox ratio revealed a degenerate sequence with strong homology with the binding site for ArcA. Deletion of arcA resulted in acetate reduction and increased the biomass yield due to the increased capacities of the TCA cycle and respiration. Acetate formation was completely eliminated by reducing the redox ratio through expression of NADH oxidase in the arcA mutant, even at a very high glucose consumption rate. The results provide a basis for studying new regulatory mechanisms prevalent at reduced NADH/NAD ratios, as well as for designing more efficient bioprocesses.

Glucose consumption rate critically depends on redox state in Corynebacterium glutamicum under oxygen deprivation

2015 ◽  
Vol 99 (13) ◽  
pp. 5573-5582 ◽  
Author(s):  
Yota Tsuge ◽  
Kimio Uematsu ◽  
Shogo Yamamoto ◽  
Masako Suda ◽  
Hideaki Yukawa ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Redox State ◽  
Consumption Rate ◽  
Glucose Consumption ◽  
Oxygen Deprivation ◽  
Glucose Consumption Rate

Assay of the Glucose Consumption Rate in Liver with a Novel Colorimetric Method

2011 ◽  
Vol 7 (3) ◽  
pp. 195-201 ◽  
Author(s):  
Zhicai Zhang ◽  
Xin Li ◽  
Mingxia Chen ◽  
Wangli Shen
Keyword(s):  
Consumption Rate ◽  
Colorimetric Method ◽  
Glucose Consumption ◽  
Glucose Consumption Rate

Physiological implications of class IIa bacteriocin resistance in Listeria monocytogenes strains

Microbiology ◽  
2004 ◽  
Vol 150 (2) ◽  
pp. 335-340 ◽  
Author(s):  
Viveka Vadyvaloo ◽  
Jacky L. Snoep ◽  
John W. Hastings ◽  
Marina Rautenbach
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Consumption Rate ◽  
Biomass Yield ◽  
Specific Growth ◽  
Glucose Consumption ◽  
Acid Fermentation ◽  
Lower Growth ◽  
Glucose Consumption Rate ◽  
Resistant Strains

High-level resistance to class IIa bacteriocins has been directly associated with the absent EIIABMan (MptA) subunit of the mannose-specific phosphoenolpyruvate-dependent phosphotransferase system (PTS) () in Listeria monocytogenes strains. Class IIa bacteriocin-resistant strains used in this study were a spontaneous resistant, L. monocytogenes B73-MR1, and a defined mutant, L. monocytogenes EGDe-mptA. Both strains were previously reported to have the EIIABMan PTS component missing. This study shows that these class IIa bacteriocin-resistant strains have significantly decreased specific growth and glucose consumption rates, but they also have a significantly higher growth yield than their corresponding wild-type strains, L. monocytogenes B73 and L. monocytogenes EGDe, respectively. In the presence of glucose, the strains showed a shift from a predominantly lactic-acid to a mixed-acid fermentation. It is here proposed that elimination of the EIIABMan in the resistant strains has caused a reduced glucose consumption rate and a reduced specific growth rate. The lower glucose consumption rate can be correlated to a shift in metabolism to a more efficient pathway with respect to ATP production per glucose, leading to a higher biomass yield. Thus, the cost involved in obtaining bacteriocin resistance, i.e. losing substrate transport capacity leading to a lower growth rate, is compensated for by a higher biomass yield.

scholarly journals Choline-Based Ionic Liquids as Media for the Growth of Saccharomyces cerevisiae

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 471 ◽  
Author(s):  
Magaret Sivapragasam ◽  
Cecilia Devi Wilfred ◽  
Joshua Raj Jaganathan ◽  
Sooridarsan Krishnan ◽  
Wan Azlina Wan Ab Wan Karim Ghani
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ionic Liquids ◽  
Consumption Rate ◽  
Glucose Consumption ◽  
Growth Media ◽  
Dihydrogen Phosphate ◽  
Media Composition ◽  
Glucose Consumption Rate ◽  
The Media ◽  
Synthetic Media

Ionic liquids (ILs) have garnered great attention as alternative solvents in many biological reactions and applications. However, its unknown toxicity is in line with the challenges to use it for biological applications. In this study, three choline based Ionic Liquids—choline saccharinate (CS), choline dihydrogen phosphate (CDHP), and choline tryptophanate (CT) were assessed for their suitability on the growth of Saccharomyces cerevisiae. The ILs were incorporated into the growth media of S. cerevisiae (defined as synthetic media) to access its potential as a substitute to conventional media. The compatibility of the synthetic media was evaluated based on the toxicity (EC50), growth curve, and glucose profile. The results showed that the incorporation of CDHP and CS did promote the growth of S. cerevisiae with a rapid glucose consumption rate. The growth of S. cerevisiae with the media composition of yeast extract, peptone, and CS showed improvement of 13%. We believe that these observations have implications in the biocompatibility studies of ILs to microorganisms.

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