scholarly journals Biodegradation of Phenol by Rhodococcus sp. Strain SKC: Characterization and Kinetics Study

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3665
Author(s):  
Yujuan Wen ◽  
Chaofan Li ◽  
Xiaoming Song ◽  
Yuesuo Yang
Keyword(s):  
Substrate Inhibition ◽  
Phenol Degradation ◽  
Maximum Yield ◽  
Maximum Growth ◽  
High Yield ◽  
Lag Phase ◽  
Yield Coefficient ◽  
Phenol Biodegradation ◽  
Kinetics Of ◽  
Rhodococcus Sp

This study focuses on the kinetics of a pure strain of bacterium Rhodococcus sp. SKC, isolated from phenol-contaminated soil, for the biodegradation of phenol as its sole carbon and energy source in aqueous medium. The kinetics of phenol biodegradation including the lag phase, the maximum phenol degradation rate, maximum growth rate (Rm) and maximum yield coefficient (Y) for each Si (initial phenol concentration, mg/L) were fitted using the Gompertz and Haldane models of substrate inhibition (R2 > 0.9904, RMSE < 0.00925). The values of these parameters at optimum conditions were μmax = 0.30 h−1, Ks = 36.40 mg/L, and Ki = 418.79 mg/L, and that means the inhibition concentration of phenol was 418.79 mg/L. By comparing with other strains of bacteria, Rhodococcus sp. SKC exhibited a high yield factor and tolerance towards phenol. This study demonstrates the potential application of Rhodococcus sp. SKC for the bioremediation of phenol contaminate.

An appropriate physiological control for environmental temperature studies: comparative growth kinetics of winter rye

1984 ◽  
Vol 62 (5) ◽  
pp. 1062-1068 ◽  
Author(s):  
M. Krol ◽  
M. Griffith ◽  
N. P. A. Huner
Keyword(s):  
Low Temperature ◽  
Leaf Area ◽  
Growth Response ◽  
Dry Weight ◽  
Maximum Growth ◽  
Cold Hardening ◽  
Lag Phase ◽  
Winter Rye ◽  
Kinetics Of ◽  
Leaf Dry Weight

The accurate interpretation of physiological and biochemical alterations observed in plants grown under contrasting environmental conditions requires knowledge of their relative physiological ages. For this purpose, we compared the growth kinetics of winter rye (Secale cereale L. cv. Puma) at nonhardening and cold-hardening temperatures. Growth at nonhardening temperatures was characterized by a 10-day lag phase with the attainment of maximum growth after about 28 days. Growth at cold-hardening temperatures resulted in an extension of the lag phase to about 21 days with maximum growth being attained after 56 days. The calculated growth coefficient at cold-hardening temperatures was 35–40% of that at nonhardening temperatures. This relationship was consistent with growth parameters such as leaf dry weight, fresh weight, and area, but not with plant height. Although total leaf dry weight and total number of leaves per plant did not differ between nonhardened and cold-hardened plants at maximum growth, total leaf area per plant and stretched plant height was 3- to 4-times greater in nonhardened than in cold-hardened plants. This resulted in a fourfold increase in leaf dry weight per leaf area during growth at low temperature in contrast to the maintenance of a constant ratio during growth at nonhardening conditions. The increase in this ratio during low temperature growth was, in part, accounted for by a decrease in water content and an increase in cytoplasmic content. These results were confirmed by the investigation of growth on an individual leaf basis. However, the growth response of leaves 1 and 2 differed from that of leaves 3 and 4 when the leaf dry weight: leaf area ratio was measured as a function of time at cold-hardening temperatures. This indicates that the stage of leaf development influences its growth response to an altered environment. The results of the development of leaf freezing tolerance indicated that maximum vegetative growth appeared to coincide with maximum freezing tolerance of leaves from cold-hardened plants (−22 °C) but not of leaves from unhardened plants (−11 °C).

Biodegradation of High Phenol Concentration in a Membrane Bioreactor

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Benoît Marrot ◽  
Adrian Barrios-Martinez ◽  
Philippe Moulin ◽  
Nicolas Roche
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Membrane Bioreactor ◽  
Substrate Inhibition ◽  
Phenol Degradation ◽  
Phenol Concentration ◽  
Phenol Removal ◽  
Permeate Flux ◽  
Phenol Biodegradation ◽  
Haldane Model

Phenol biodegradation by mixed culture was studied in a membrane bioreactor (MBR) over a period of 285 days. Activated sludge was used as the MBR biomass, after controlled acclimation to high phenol concentrations. The MBR permeate flux was stabilized quickly (in a few hours) and always maintained above 90 L.h-1.m-2.bar-1. The acclimatized activated sludge allowed significant phenol degradation (95% average COD removal efficiency and greater than 99% phenol removal efficiency) without supplemental reagent addition. After sludge acclimatization, the Haldane kinetics model for a single substrate was used to obtain the maximum specific growth rate (µm = 0.438 h-1), the half saturation coefficient (Ks = 29.54 mg.L-1) and the substrate inhibition constant (Ki = 72.45 mg.L-1). Biodegradation experiments were conducted at different phenol concentrations (4.9 – 8.5 g.L-1 d-1). Although the phenol concentration was high, the Haldane model was still acceptable, and removal capacities were in agreement with literature. Excellent effluent quality was obtained regardless of the extremely short SRT (5 – 17 days). This work shows the potential of MBR for toxic chemical elimination, charged effluents treatment and process stability.

The highest inhibition coefficient of phenol biodegradation using an acclimated mixed culture

2015 ◽  
Vol 73 (5) ◽  
pp. 1033-1040 ◽  
Author(s):  
Mojtaba Mohseni ◽  
Payman Sharifi Abdar ◽  
S. Mehdi Borghei
Keyword(s):  
Mixed Culture ◽  
Degradation Rate ◽  
Growth Parameters ◽  
Removal Rate ◽  
Substrate Inhibition ◽  
Phenol Degradation ◽  
Oxygen Demand ◽  
Synthetic Wastewater ◽  
Phenol Biodegradation ◽  
Culture Substrate

In this study a membrane biological reactor (MBR) was operated at 25 ± 1 °C and pH = 7.5 ± 0.5 to treat synthetic wastewater containing high phenol concentrations. Removal efficiencies of phenol and chemical oxygen demand (COD) were evaluated at four various hydraulic retention times (HRTs) of 24, 12, 8, and 4 hours. The removal rate of phenol (5.51 kg-Phenol kg-VSS−1 d−1), observed at HRT of 4 h, was the highest phenol degradation rate in the literature. According to COD tests, there were no significant organic matter in the effluent, and phenol was degraded completely by mixed culture. Substrate inhibition was calculated from experimental growth parameters using the Haldane, Yano, and Edward equations. The results show that the Haldane equation is fitted to the experimental data in an excellent manner. Kinetic parameters were derived by nonlinear regression with a correlation coefficient (R2) of 0.974. The values for Haldane constants μmax, Ks, and Ki were 0.3085 h−1, 416 mg L−1 and 1,886 mg L−1, respectively. The Ki value is the highest value obtained for mixed cultures degrading phenol under batch conditions.

Substrate Inhibition Kinetics of Phenol Biodegradation

2000 ◽  
Vol 72 (1) ◽  
pp. 50-55 ◽  
Author(s):  
Chetan T. Goudar ◽  
Shobha H. Ganji ◽  
Basayya G. Pujar ◽  
Keith A. Strevett
Keyword(s):  
Substrate Inhibition ◽  
Inhibition Kinetics ◽  
Phenol Biodegradation ◽  
Substrate Inhibition Kinetics ◽  
Kinetics Of

Substrate Inhibition Kinetics of Phenol Degradation by Pseudomonas aeruginosa and Pseudomonas fluorescence

2004 ◽  
Vol 4 (1) ◽  
pp. 56-61 ◽  
Author(s):  
B.O. Oboirien . ◽  
B. Amigun . ◽  
T.V. Ojumu . ◽  
O.A. Ogunkunle . ◽  
O.A. Adetunji . ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Substrate Inhibition ◽  
Phenol Degradation ◽  
Inhibition Kinetics ◽  
Substrate Inhibition Kinetics ◽  
Kinetics Of

The effect of heterotrophic yield on the assessment of the correction factor for anoxic growth

1996 ◽  
Vol 34 (5-6) ◽  
pp. 67-74 ◽  
Author(s):  
D. Orhon ◽  
S. Sözen ◽  
N. Artan
Keyword(s):  
Correction Factor ◽  
Domestic Sewage ◽  
Yield Coefficient ◽  
Heterotrophic Growth ◽  
Metabolic Processes ◽  
Anoxic Conditions ◽  
Industrial Wastewaters ◽  
Systems Modelling ◽  
Kinetics Of ◽  
Very High

For single-sludge denitrification systems, modelling of anoxic reactors currently uses the kinetics of aerobic heterotrophic growth together with a correction factor for anoxic conditions. This coefficient is computed on the basis of respirometric measurements with the assumption that the heterotrophic yield remains the same under aerobic and anoxic coditions. The paper provides the conceptual proof that the yield coefficient is significantly lower for the anoxic growth on the basis of the energetics of the related metabolic processes. This is used for the interpretation of the very high values for the correction factor experimentally determined for a number of industrial wastewaters. A default value for the anoxic heterotrophic yield coefficient is calculated for domestic sewage and compatible wastewaters and proposed for similar evaluations.

scholarly journals Kinetics of tau aggregation reveals patient specific tau characteristics among Alzheimer's cases

2021 ◽  
Author(s):  
Tarun V Kamath ◽  
Naomi Klickstein ◽  
Caitlin Commins ◽  
Analiese R Fernandes ◽  
Derek H Oakley ◽  
...  
Keyword(s):  
Growth Phase ◽  
Tau Proteins ◽  
Patient Specific ◽  
Lag Phase ◽  
Plateau Phase ◽  
Kinetic Assay ◽  
Cellular Processes ◽  
Morphological Differences ◽  
Tau Aggregation ◽  
Kinetics Of

Abstract The accumulation of tau aggregates throughout the human brain is the hallmark of a number of neurodegenerative conditions classified as tauopathies. Increasing evidence shows that tau aggregation occurs in a “prion-like” manner, in which a small amount of misfolded tau protein can induce other, naïve tau proteins to aggregate. Tau aggregates have been found to differ structurally among different tauopathies. Recently, however, we have suggested that tau oligomeric species may differ biochemically among individual patients with sporadic Alzheimer disease, and have also showed that the bioactivity of the tau species, measured using a cell-based bioassay, also varied among individuals. Here, we adopted a live-cell imaging approach to the standard cell-based bioassay to explore further whether the kinetics of aggregation also differentiated these patients. We found that aggregation can be observed to follow a consistent pattern in all cases, with a lag phase, a growth phase, and a plateau phase, which each provide quantitative parameters by which we characterize aggregation kinetics. The length of the lag phase and magnitude of the plateau phase are both dependent upon the concentration of seeding-competent tau, the relative enrichment of which differs among patients. The slope of the growth phase correlates with morphological differences in the tau aggregates, which may be reflective of underlying structural differences. This kinetic assay confirms and refines the concept of heterogeneity in the characteristics of tau proteopathic seeds among individuals with Alzheimer’s disease and is a method by which future studies may characterize longitudinal changes in tau aggregation and the cellular processes which may influence these changes.

scholarly journals Kinetics of Non-Enzymatic Synthesis of Dipeptide Cbz-Phe-Leu with AOT Reversed Micelles

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1003
Author(s):  
Michiaki Matsumoto ◽  
Tadashi Hano
Keyword(s):  
Enzymatic Synthesis ◽  
Maximum Yield ◽  
Side Reactions ◽  
Experimental Conditions ◽  
Operational Conditions ◽  
Ph Dependency ◽  
Optimum Water Content ◽  
Short Time ◽  
Kinetics Of ◽  
Aot Reversed Micelles

The non-enzymatic synthesis of N-benzyloxycarbonyl-L-phenylalanyl-L-leucine (Cbz-Phe-Leu) from lipophilic N-benzyloxycarbonyl-L-phenylalanine (Cbz-Phe) and hydrophilic L-leucine (Leu), by N, N’-dicyclohexylcarbodiimide (DCC) as a condensing agent, was carried out using a reversed micellar system composed of bis(2-ethylhexyl) sodium sulfosuccinate (AOT) as a surfactant and isooctane. We successfully synthesized Cbz-Phe-Leu in a short time and investigated the effects of its operational conditions, the DCC concentration, w0, and the pH on the kinetic parameters and the maximum yields. For dipeptide synthesis, we had to add an excess of DCC with the substrates because of the side reactions of Cbz-Phe. From the pH dependency of the reactivity, a partially cationic form of Leu was better for a synthesis reaction because of the enrichment of Leu at the interface by anionic AOT. The optimum water content on the dipeptide synthesis was w0 = 28 due to the competition of the peptide synthesis and the side reactions. The maximum yield of Cbz-Phe-Leu was 0.565 at 80 h under optimum experimental conditions.

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