Electrochemical Evaluation of Bacterial Activity

2020 ◽  
Author(s):  
So Tanabe ◽  
Shuyi Sun ◽  
Satohiro Itagaki ◽  
Kazuki Urai ◽  
Hiroshi Shiigi
Keyword(s):  
Tricarboxylic Acid Cycle ◽  
Carbon Sources ◽  
Shewanella Oneidensis ◽  
Reduction Reaction ◽  
Enzymatic Reactions ◽  
Bacterial Cells ◽  
Electron Generation ◽  
Bacterial Cell Viability ◽  
Live Bacterial Cells ◽  
Electrochemical Evaluation

For the efficient utilization of bacterial bioresources, the quantitative evaluation of metabolic activity in live bacterial cells is required. Using potentiometric measurements, we quantitatively evaluated the electron generation rate of Shewanella oneidensis MR-1 based on individual enzymatic reactions. We evaluated intracellular electron generation in bacterial suspensions supplemented with different carbon sources utilized in the tricarboxylic acid cycle. In bacterial suspensions, ferricyanide was almost completely reduced to ferrocyanide by cell-generated electrons, without an effect on bacterial cell viability. Focusing on this reduction reaction, quantitative evaluations were possible by potentiometry based on the Nernst equation.

Removal of aflatoxin b1 and t-2 toxin by bacteria isolated from commercially available probiotic dairy foods

2021 ◽  
pp. 108201322098791
Author(s):  
Walter Ondiek ◽  
Yaling Wang ◽  
Lijun Sun ◽  
Langhua Zhou ◽  
Stephen LW On ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Cells ◽  
Toxin Concentration ◽  
Dairy Foods ◽  
Heat Treated ◽  
Toxin Removal ◽  
Bacterial Cell Viability ◽  
Aflatoxin B ◽  
Live Bacterial Cells

This study isolated lactic acid bacteria from commercially available probiotic foods to determine their capacity to remove aflatoxin B1 (AFB1) and trichothecene-2 (T-2). The removal rates by original live and heat-treated cells of lactic acid bacteria (LAB) were compared to test the effect of heat treatment on efficacy. LAB is capable to remove up to 46% of AFB1 and up to 45% of T-2 toixn. The toxin removal capability increased as toxin concentration increased despite bacterial cell viability declining. Surprisingly, the denatured LAB removed greater percentages of AFB1 (up to 62%) and T-2 (up to 52%) than live bacterial cells ( P < 0.05), lending support to the hypothesis that there is higher binding of toxins to the cell membrane of nonviable cells. The research provided practical evidences, which suggest that when ingested into the gut biota, LAB could likely reduce absorption of AFB1 and T-2 from contaminated foods.

Real-time monitoring and inhibition of the activity of carbapenemase in live bacterial cells: application to screening of β-lactamase inhibitors

2020 ◽  
Vol 44 (46) ◽  
pp. 20334-20340
Author(s):  
Han Gao ◽  
Ying Ge ◽  
Min-Hao Jiang ◽  
Cheng Chen ◽  
Le-Yun Sun ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Real Time ◽  
Bacterial Cells ◽  
Real Time Monitoring ◽  
Live Bacterial Cells

Antibiotic resistance mediated by β-lactamases including metallo-β-lactamases (MβLs) has become an emerging threat.

Significance of External Carbon Sources on Simultaneous Removal of Nutrients from Wastewater

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1047-1055 ◽  
Author(s):  
N. F. Y. Tam ◽  
Y. S. Wong ◽  
G. Leung
Keyword(s):  
Sodium Acetate ◽  
Batch Reactor ◽  
Inorganic Nitrogen ◽  
Carbon Sources ◽  
Simultaneous Removal ◽  
Bacterial Cells ◽  
High Concentration ◽  
P Content ◽  
Carbon Substrates ◽  
Effective Source

Laboratory-scale studies were undertaken to examine the effects of easily-biodegradable organic substances upon the nutrient removal by a simulated sequencing batch reactor (SBR). The fill and react period of the SBR was 14 hours, including an instant fill, 7 hours aeration, 4 hours anoxic and 3 hours aeration period. Three kinds of commonly used carbon sources, namely methanol, glucose and sodium acetate, at the concentrations equivalent to theoretical COD values of 50, 100 and 150 mg O2 l-1 were added to each reactor prior to the anoxic stage. The results showed that the concentration of NH4+-N dropped from its initial 50 to 18 mg l-1 (64 % removal) during the first aeration period, with the NO3−-N content increased from 2 to 33 mg l−1. A 60% depletion of COD was also recorded in this period. Denitrification occurred during the anoxic period, higher amount of NO3−1-N was removed in the reactors supplemented with carbon substrates at the concentrations of 100 and 150 mg l-1. The final inorganic nitrogen content was less than 5 mg l-1 in the reactor supplemented with 150 mg l-1 sodium acetate. Simultaneous removal of phosphorus was reported in reactors supplied with high concentration of sodium acetate. In these reactors, large amount of P was released during the anoxic/anaerobic period but the released P was taken up by bacterial cells in the subsequent aeration stage, and the final P content was less than 1.5 mg l-1 (84 % removal was achieved). Among the three carbon sources used, sodium acetate was the most efficient and effective source in removing wastewater nutrients, followed by methanol, and glucose was the least reliable substrate.

The role of iron in the preparation and oxygen reduction reaction activity of nitrogen-doped carbon

2015 ◽  
Vol 51 (12) ◽  
pp. 2450-2453 ◽  
Author(s):  
Dae-Soo Yang ◽  
Min Young Song ◽  
Kiran Pal Singh ◽  
Jong-Sung Yu
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Carbon Sources ◽  
Reduction Reaction ◽  
Acidic Media ◽  
Oxygen Reduction Reaction Activity ◽  
Exact Role ◽  
Ordered Mesoporous ◽  
Nitrogen Doped Carbon

The exact role of iron in catalyzing oxygen reduction reaction in both alkaline and acidic media is portrayed with unique platelet ordered mesoporous carbon prepared using Fe-phthalocyanine as iron, nitrogen and carbon sources.

scholarly journals Effect of milk chocolate supplementation with lyophilised Lactobacillus cells on its attributes

2010 ◽  
Vol 28 (No. 5) ◽  
pp. 392-406 ◽  
Author(s):  
D. Żyżelewicz ◽  
E. Nebesny ◽  
I. Motyl ◽  
Z. Libudzisz
Keyword(s):  
Ambient Temperature ◽  
High Temperatures ◽  
Functional Food ◽  
Lactobacillus Casei ◽  
Probiotic Bacteria ◽  
Live Cells ◽  
Bacterial Cells ◽  
Bacterial Strains ◽  
Milk Chocolate ◽  
Live Bacterial Cells

Manufacturing of novel foodstuffs supplemented with live probiotic bacteria has recently been intensively investigated. The supplementation of confectionery with probiotics is troublesome since some unit technological processes are conducted at high temperatures and the products are usually stored at ambient temperature. Our group has developed a method of the production of milk chocolate, sweetened with either sucrose or isomalt and aspartame, containing 32, 36, or 40 g/100 g fat, and supplemented with live cells of probiotic bacterial strains: Lactobacillus casei and paracasei. This new milk chocolate displayed the same sensory properties as the reference, probiotic-free chocolate. The number of live bacterial cells was maintained at the functional level of 10<sup>6</sup> &divide; 10<sup>8</sup> cfu/g after keeping for 12 months irrespective of the temperature. The highest number of live probiotic bacteria survived in the chocolate kept at 4&deg;C. Thus the product can be regarded as functional food.

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