Effect of Microbial Count of P. aeruginosa on Biodegradation of Crude Oil Contaminated Water

Abstract

The effect of microbial count of Pseudomonas aeruginosa bacteria amended with 20 g of nitrogen-phosphorous-potassium (NPK) fertilizer (15:15:15) on the biodegradation of crude oil-contaminated water was studied. Four samples, S ₁, S ₂, S ₃, and S ₄, with equal crude oil pollution load were inoculated with, 1 × 10⁵ cfu, 2 × 10⁵ cfu, 4 × 10⁵ cfu and 8 × 10⁵ cfu of P. aeruginosa respectively, and 20 g of NPK (15:15:15) fertilizer. The control sample, Sc, had only 8 × 10⁵ cfu P. aeruginosa and no fertilizer.

Parameters such as oil and grease content, pH, BOD, COD, and turbidity were monitored over a nine-week period. At the end of the biodegradation period, a high percentage of oil and grease content was removed. The value reduced from 185.0 to 41.50 mg/L, 24.6 mg/L, 20.5 mg/L, 13.2 mg/L, 10.9 mg/L for S _c , S ₁, S ₂, S ₃, and S ₄ respectively. There was also a drop in BOD, COD, turbidity, and pH of the samples under consideration. The S ₄ sample had the highest reduction in both BOD and COD values. The initial value dropped from 82.0 to 27.5 mg/L and 158.4 to 64.8 mg/L for the BOD and COD, respectively. These values obtained fall within the Federal Environmental Protection Agency (FEPA) limits. The oil and grease content for S ₄ sample was also reduced from 185 mg/L to 9.95 mg/L, while the pH value for this same sample, S ₄, was 6.60 after the nine-week period of investigation.     

Concentration of heavy metals in the food chain components of the nearshore coastal waters of Kalpakkam,southeast coast of India

Kalpakkam, located on the southeast coast of India, has witnessed intense nuclear power plant activities resulting in a substantial increase in social and industrial development. This has prompted the study of the concentrations of heavy metals in water, sediment, zooplankton and fish in the coastal waters of Kalpakkam to understand their pattern of distribution and bioaccumulation. The concentrations of metals were in the order Fe > Zn > Pb > Cr > Mn > Ni > Cu > Cd > Co in water, Fe > Zn > Mn > Pb > Cr > Cu > Ni > Cd > Co in zooplankton, Fe > Zn > Cu > Mn > Cr > Pb in fish and Fe > Cu > Zn > Pb > Cr > Ni > Cd in sediment. Metal concentrations in plankton were much higher than those in water, sediment and fish. The results showed wide variations in heavy metal concentrations in four food web components. The major sources of metals on the Kalpakkam coast are land-based anthropogenic ones. The coastal sediment is moderately polluted with Cu & Cd. Relatively low dissolved metal concentrations were observed when compared to other coastal waters. However, the results indicated that dermal absorption (CDIdermal) of Fe might be a matter of concern due to its carcinogenicity. The summer season had higher Metal Pollution Index (MPI) values, than the rest of the year. Metal pollution indices indicated that southwest monsoon (SWM) and northeast monsoon (NEM) periods had lower contamination (MPI: 1.0–2.0; Class-III) than the summer season (MPI: 2.0–4.0; Class-IV). The bioaccumulation of metal is faster and the content is much higher in zooplankton than in fish. Bioconcentration factors (BCF) were significantly different for different metals. Amongst the toxic metals the BCF was highest for Cr for both zooplankton and fish tissue. The metal concentrations in the fish species studied were sufficiently low that the fish tissue was safe for human consumption.     

Evaluation of isothermal kinetics of the thermal decomposition of guanidine nitrate in constant volume

ABSTRACT

In this paper, thermal decomposition characteristics of guanidine nitrate (GN) are studied by both dynamic and isothermal differential scanning calorimetry (DSC) tests in constant volume. The dynamic curve (1°C/min) shows that at least two overlapped peaks exist in the decomposition curve of GN, whereas the decomposition peaks of each isothermal experiment (305–320°C) can be clearly taken as a combination of three decomposition peaks. Besides, an isothermal kinetic model is studied. AKTS is used to decouple the isothermal decomposition peaks, to obtain three separate peaks, i.e., one decelerating model peak and two sigmoidal model peaks. An Nth order kinetic model is established for the first decomposition stage, and an autocatalytic model is established to describe the left two stages. The kinetic parameters of each stage are calculated by nonlinear fitting. The equation describing the reaction rate for the Nth order kinetic model as below, dα/dt = exp(8.92)exp(?67730/RT)(1?α)^1.020, the second and the third steps can be described by the equations of dα/dt = exp(26.15)exp(?165570/RT)(1-α)^0.508+ exp(23.87)exp(?159360/RT)(1-α)^0.508α^0.150 and dα/dt = exp(24.03) exp(?166070/RT)(1-α)^0.082+exp(23.28)exp(?160000/RT)(1?α)^0.082α^0.210, respectively. The results calculated by these models fit well the experimental data, proving that the kinetic parameters are reliable and accurate.     

Modeling of formation of petroleum biomarker hydrocarbons by thermolysis and thermocatalysis of bacterium biomass

Thermolysis and thermocatalysis of the insoluble part of chemoorganoheterotrophic aerobic bacteria Arthrobacter sp. RV and Pseudomonas aeruginosa RM have been performed. The thermolyzates and thermocatalyzates of these bacteria contain the hydrocarbon biomarkers n-alkanes, isoprenanes, steranes, and terpanes. Of n-alkanes, the C₉-C₃₅ hydrocarbons with unimodal distribution formed in the products of or C₉-C₃₉ n-alkanes with bimodal distribution are produced by thermolysis or thermocatalysis, respectively. n-Alkanes with odd number of carbon atoms in the molecule prevail over the even counterparts (n-C₉, n-C₁₁, n-C₁₅, and n-C₁₇) in the thermolysis products of both strains, whereas n-alkanes with even number of carbon atoms (n-C₁₆, n-C₁₈, and n-C₂₀) dominate in the thermocatalyzates. Isoprenanes of the C₁₃-C₂₀ composition are generated. It is noteworthy that regular C₁₇ isoprenane has been found for the first time among isoprenanes. The cyclic biomarker hydrocarbon steranes and terpanes are simultaneously generated, with the distribution of C₂₇-C₂₉ regular steranes resembles that in marine oils generated in argillaceous strata. At the same time, the adiantane to hopane ratio (H₂₉/H₃₀) is characteristic of the organic matter generated in carbonate strata.     

Inactivation of Salmonella Typhimurium and quality preservation of cherry tomatoes by in-package aerosolization of antimicrobials

The purpose of the present study was to investigate the efficacy of in-package aerosolized aqueous sanitizers in reducing populations of Salmonella enterica serovar Typhimurium on tomato fruit and in maintaining fruit quality. Cherry tomatoes were inoculated with a cocktail of attenuated S. Typhimurium ATCC 53647 and 53648 strains on the smooth skin surface and stem scar area. Next, 200 ppm free chlorine, and peroxyacetic acid (PAA) and aqueous ClO₂ at different concentrations, 2% lactic acid + 2% acetic acid + 2% levulinic acid, and 3% acetic acid + 3% lactic acid were aerosolized into a clamshell container containing cherry tomatoes. Results showed that S. Typhimurium populations on smooth tomato surfaces were reduced by more than 5 log CFU/fruit with 400 ppm PAA, 2% lactic acid + 2% acetic acid + 2% levulinic acid, 3% acetic acid + 3% lactic acid, and aqueous ClO₂ (100 and 400 ppm). On the stem scar area, 400 ppm aqueous ClO₂ was more effective in reducing S. Typhimurium populations than other treatments, achieving 4.89 log CFU/fruit reduction, followed by 400 ppm PAA (2.62 log CFU/fruit). The efficacy of ClO₂ and acid combination treatments increased during 3-week storage at 10 °C, achieving >3 log CFU/fruit inactivation with the acid combination and ca. 6 log with for 400 ppm with ClO₂. None of the treatments significantly (p > 0.05) affected color, appearance, firmness, vitamin C, lycopene or antioxidant values of tomatoes during 3 weeks of storage; although, an acidic odor was detected for samples treated with the organic acids in the earlier period of the storage. These results suggest that in-package aerosolized sanitizers can be used as a novel method for the inactivation of Salmonella on tomato fruit.     

松辽盆地南部深层火山岩识别及成藏条件分析

松辽盆地北部徐深1井在营城组火山岩获得油气突破后，在松辽盆地南部长岭断陷针对火山岩部署了长深1井。在长深1井营城组火山岩地层测试获4.6×105m3/d的工业气流，推算无阻流量1.5×106m3/d以上，预示松辽盆地南部深层火山岩气藏是下步勘探开发的主要领域。通过大量的火山岩岩心资料，利用岩石学、矿物学、测井和地震地层学等多学科技术，首次在松辽盆地南部建立了火山岩识别标准，在东南隆起区部署探井1口，在火山岩中见到了较好的气显示，取得很好的效果。     

Transfer of Listeria monocytogenes during mechanical slicing of onions

A series of recalls in 2012 involving diced yellow onions contaminated with Listeria monocytogenes from one manufacturer has heightened public health concerns surrounding the preparation, handling and use of raw onions. In response, this study aimed to quantify the extent of L. monocytogenes transfer during mechanical slicing of onions. Spanish yellow onions (Allium cepa) were dip-inoculated in a 3-strain avirulent L. monocytogenes cocktail (M3, J22F and J29H) to contain ∼8.6, 6.8, or 5.9 log CFU/onion. After air-drying, one inoculated onion was sliced using a mechanical hand slicer, followed by twenty uninoculated onions with the first, fourth, and last slices collected for Listeria analysis. Each sample was added to UVM medium, homogenized by stomaching, appropriately diluted and then plated, with or without prior membrane filtration, on Modified Oxford Agar with the plates incubated at 35 °C for 48 h. All UVM samples were enriched for 48 h and then streaked to MOX if Listeria was not quantifiable by direct plating. After slicing one onion inoculated at 8.6 log CFU/onion followed by 20 uninoculated onions, onions 1, 10 and 20 yielded average Listeria populations of 6.7, 3.8, and 2.7 log compared to 3.2, 1.6, and 1.7 log CFU/onion and 3.6, 1.3, and 0.9 log CFU/onion when the initial onion contained 6.8 and 5.9 CFU/onion, respectively. Listeria transfer during onion slicing was best described using an exponential decay model which should help to further the understanding of Listeria transfer during onion processing and provide the industry with guidelines to improve end product safety.     

Effect of UV-C irradiation on the inactivation of inoculated pathogens and quality of chicken breasts during storage

In this study, we evaluated the inactivation of foodborne pathogens inoculated on chicken breasts by UV-C treatment. Chicken breasts were inoculated with Campylobacter jejuni, Listeria monocytogenes, and Salmonella enterica serovar Typhimurium at 6–7 log CFU/g. The inoculated chicken breasts were then irradiated with UV-C light of dose 0, 0.5, 1, 3, and 5 kJ/m². Microbiological data indicated that the populations of the foodborne pathogens decreased significantly (p < 0.05) with increasing UV-C irradiation. In particular, UV-C irradiation at 5 kJ/m² reduced the initial populations of C. jejuni, L. monocytogenes, and S. typhimurium by 1.26, 1.29, and 1.19 log CFU/g, respectively. After UV-C irradiation, the samples were individually packed using polyethylene terephthalate containers and stored at 4 ± 1 °C for 6 d. The pH of the control increased more than the samples irradiated at 0.5, 1, 3, and 5 kJ/m², while TBARS values increased during storage regardless of UV-C irradiation. UV-C irradiation caused negligible changes in Hunter L, a, and b values. These results suggest that UV-C irradiation can be useful in improving the microbial safety of chicken breasts during storage, without impairing quality.     

Oxidation of alcohols involving two types of peroxyl radicals

Liquid-phase oxidation of alcohols (R¹R²CHOH) occurs as a chain reaction involving two peroxyl radicals, namely, R¹R²C(OH)O ₂ ^· and HO ₂ ^· . Using the model of crossing parabolas, the activation energy and the rate constant were calculated for the reactions of α-hydroperoxyl radicals with four alcohols. A kinetic analysis of this reaction as a two-center chain process in which two peroxyl radicals that differ in reactivity (R¹R²C(OH)O ₂ ^· and HO ₂ ^· ) participate in chain propagation was performed. The relative amounts of the peroxyl radicals and their contribution to chain propagation under different oxidation conditions (temperature, alcohol concentration) were calculated for the oxidation of four alcohols: ethanol, 2-propanol, cyclohexanol, and α-phenylethanol. A change in the ratio between radicals due to the accumulation of a carbonyl compound and the fast addition of hydroperoxyl radicals to the carbonyl group during alcohol oxidation was considered and its effect on the chain propagation step in the oxidation reaction was discussed.     

Effect of Recycle Gas Composition of the Performance of Fischer-Tropsch Catalyst

Abstract

In this study, the influence of CO₂ and CH₄ on the performance and selectivity of Co-Ru/Al₂O₃ catalyst is investigated by injection of these gases (0–20 vol.% of feed) to the feed stream. The effect of temperature and feed flow rate are also inspected. The results show that low amounts of CO₂ in the feed stream do not change the catalyst activity, but increasing the amount of CO₂ (more than 10 vol.%), causes the CO conversion to decrease and the selectivity of heavy components to increase. Methane acts as an inert gas and does not affect the catalyst performance. Increasing feed flow rate has a negative effect on both CO conversion and heavy component selectivity. By raising the temperature, CO conversion will increase but there are more volatile components in the product. The effect of CO₂ on catalyst deactivation is also investigated and a mechanism is suggested to explain the negative influence of CO₂ on catalyst deactivation.     

An Experimental Study of the Explosion Parameters of Vapor-Liquid Mixtures of Nitroethane/Air

The explosion hazards characterizing vapor-liquid mixtures (mists) are commonly overlooked, resulting in significant damage within processing industries that use these mixtures. This article presents new experimental data that enable the quantitative evaluation of the effects of vapor-liquid mixtures of nitroethane/air on various explosion parameters. A series of experiments was conducted as follows: First, at mean Sauter mean diameter (SMD, D₃₂=6V_p/A_p, where A_p and V_p are the surface area and volume of the particle, respectively) values of 19.33 and 33.75 μm, two sets of vapor-liquid mixtures of nitroethane/air at various concentrations were obtained. Subsequently, experiments were conducted, and the explosion pressure and temperature of the two sets of vapor-liquid mixtures of nitroethane/air at various concentrations were analyzed. The flame temperatures and explosion pressures, maximum rate of pressure rise [dP/dt]_max, maximum rate of temperature rise [dT/dt]_max, flame propagation delay time, and lower explosion limit (LEL) were analyzed. At both mean SMD values (19.64 and 34.40 μm), the peak pressure of the vapor-liquid mixtures of nitroethane/air increased as the total concentration was increased, within the flammable range. However, the total concentration of the maximum peak temperature at a mean SMD of 19.64 μm was less than that at a mean SMD of 34.40 μm, with values of 418.38 and 631.20 g m^?3, respectively. For a similar concentration of the gaseous-phase or vapor-liquid mixture of nitroethane/air, the [dP/dt]_max of the vapor-liquid mixtures of nitroethane/air was significantly larger than that of the gaseous-phase nitroethane/air mixtures.     

Effects of high hydrostatic pressure on the inactivation of norovirus and quality of cabbage Kimchi

In Korea, cabbage Kimchi is potentially regarded as a high-risk food with respect to enteric norovirus (NoV). This study investigated the effect of high hydrostatic pressure (HPP) treatment (100–500 MPa for 5 min at room temperature) on the inactivation of murine norovirus-1 (MNV-1, initial inoculum of 5–6 log₁₀ PFU/ml) as a human NoV surrogate in the Kimchi. The effects of HHP treatment on the microbiological, physicochemical properties and sensory qualities of cabbage Kimchi were also examined. The MNV-1 in the Kimchi after 100, 200, 300, and 400 MPa were 5.6 (0.1 log reduction), 5.5 (0.2 log reduction), 5.4 (0.3 log reduction), and 4.2 (1.5 log₁₀ PFU/ml), respectively. Complete inactivation of MNV-1 was determined in the cabbage Kimchi by 500 MPa. One-log reduction of total aerobic bacteria and lactic acid bacteria was only determined in the 500 MPa HHP treated Kimchi. The pH values and acidity (%) in all HPP treated Kimchi were 4.4–5.7 and 0.4–0.7%, respectively. The Hunter colors ‘a’ (redness) and ‘b’ (yellowness) and mechanical texture (hardness) in HHP Kimchi were not different between 0 MPa and HHP (100–500 MPa) treated Kimchi significantly (P > 0.05) different although the HHP treated Kimchi turned to very slight darkness. All sensory scores in HHP treated Kimchi were determined as > 5 point (like) in 7 point-hedonic scale. The current study suggest that 500 MPa for 5 min could potentially be used for direct application in commercial Kimchi processing and distribution for complete MNV-1 inactivation without causing any deleterious overall quality changes.     

Table of Contents

• Features
• Outlook for Increased Regulatory Scrutiny Shows Importance of Compliance Programs
• David D'Alessandro, Kelly Daly, and Harvey Reiter
• Administration Prognosis—Compliance Gas
  • FERC Natural Gas Enforcement Hopefully Improved Under New Administration
  • Mark K. Lewis and D. Kirk Morgan
  • Administration Prognosis—Compliance Electricity
    • Heavy FERC Enforcement Forecast in Electric Area
    • William D. DeGrandis
    • Administration Prognosis—Environment
      • Carbon Dioxide: Regulating Emissions Following a Long and Winding Road
      • James Hempstead
      • Administration Prognosis—Strategies
        • Reshaping Agendas: Utilities at a New Frontier
        • Thomas J. Flaherty and James C. Hendrickson

• Columns
• Energy and the Environment
  • Renewables, Becoming Cheaper, Are Suddenly Passé
  • Jonathan A. Lesser

     

Table of Contents

• Features
• Federal Budget Tax Proposals—Not Good, But How Bad?
• Robert E. Willett
• New Tax Plan
  • American Recovery and Reinvestment Act and Others Afford Substantial Opportunities
  • Steven W. Snarr and Adam M. Cohen
  • Tax Use—Smart Grid
    • Carbon-Reduction Tax Dollars Better Spent on Demand Reduction, Not Megagrid Schemes
    • Paul Fenn, Robert Freehling, and David Erickson
    • Cross-Border Trade
      • Coming Soon: Natural Gas Exports From Mexico
      • Christopher J. Goncalves

• Columns
• Pipelines and Rates
  • Natural Gas and Government Policy—Can the Industry Improve Its Treatment?
  • Richard G. Smead
  • Industry Advertising and Communications
    • Gas and Electric Industries Today Require Aggressive Communications Strategies
    • Henry A. de la Garza

     

Biological control of postharvest diseases of peach with Cryptococcus laurentii

Cryptococcus laurentii was evaluated for its activity in reducing postharvest gray mold decay, blue mold decay and Rhizopus decay of peach caused by Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer respectively, and in reducing natural decay development of peach fruits. The concentrations of antagonist had significant effects on biocontrol effectiveness: the higher the concentrations of the antagonist, the lower the disease incidence. At concentrations of C. laurentii at 1 × 10⁹ CFU ml⁻¹, the gray mold decay was completely inhibited after 4 days incubation at 25 °C, while the control fruit had 50% decay, when inoculated with B. cinerea spores suspension of 1 × 10⁵ spores ml⁻¹; no complete control of the blue mold or Rhizopus mold was observed, when peach fruits were stored at 25 °C for 4 days (challenged with P. expansum) or 5 days (challenged with R. stolonifer) respectively, but the decay was distinctly prevented, the incidence of blue mold or Rhizopus mold was reduced by 78.6% or 80% respectively, compared with control, at challenged with P. expansum or R. stolonifer spores suspension of 5 × 10⁴ spores ml⁻¹, respectively. C. laurentii significantly reduced the natural development of decay and did not impair quality parameters of fruit following storage at 2 °C for 30 days followed by 20 °C for 7 days.     

Characteristics of carbon isotopes of organic alkane gases in petroliferous basins of China

Based on analytical data of gas samples from some gas- and oilfields in China, this article describes characteristics of alkane gases (C_1–4) with different origins and occurrences. It is found that δ¹³C values of organic alkane gas increase with increasing maturity (R₀). The δ¹³C values of synchronous and isogenous methane and its homologues are found to increase with the increase in carbon number of alkane gas molecules. The δ¹³C values of methane and its homologues of coal-type gas are heavier than those of corresponding components of oil-type gas, both from source rocks with the same or similar maturity. Part of the components of methane and its homologues were oxidized by bacteria which resulted in heavier carbon isotopes compared to the remaining components.     

Kinetics of thermal degradation of a Japanese oil sand

Thermal degradation characteristics of a Japanese oil sand at different heating rates (10, 20, and 30 °C/min), and 30 ml/min air flow rate have been investigated. The kinetic parameters have been calculated based on three stages of weight loss and/or the conversion of the sample. These include, stage 1 (SI): volatilization of moisture content and the light hydrocarbon (20–227 °C), stage 2 (SII): combustion of heavy hydrocarbon (227–527 °C), and stage 3 (SIII): oxidative decomposition of carbonaceous organic matter (502–877 °C). The results showed that the rate of change of the oil sand conversion with time $\left(\frac{d\alpha }{\mathit{dt}}\right)$ was affected by the heating rate. The time taken by the system to reach 0.99 conversion was observed as 85, 50, and 35 min at the heating rates of 10, 20, and 30 °C/min, respectively. The frequency factor, A, at SI was between 0.09 and 0.54 min^?1, while the activation energy, E_a, was 11.2–12.5 KJmol^?1 (the percentage weight loss, W_t, was 0–3.6 %w/w; and the conversion, α, was 0–0.2.). At SII, the values of A and E_a were 2.1–5.5 min^?1 and 17.6–19 KJmol^?1, respectively (W_t = 3.1–15.88 %w/w; α = 0.17–0.86.). The value of A at SIII was 5.5E11–1.1E13 min^?1, while E_a was 160–200 KJmol^?1 (W_t = 15.33–17.99 %w/w; and α = 0.84–0.99).     

Catalytic performance of organically templated nano nickel incorporated-rice husk silica in hydroconversion of cyclohexene and dehydrogenation of ethanol

Rice husk silica (RHS) was extracted from local rice husk by acid digestion and burning at 650 °C. RHS-Ni catalyst was prepared by dissolving RHS in 1 N NaOH and titrating with 3 N HNO₃ containing 10 wt.% Ni²⁺. The organic modifiers, either p-amino benzoic acid (A) or p-phenylenediamine (PDA) were incorporated in 5 wt.% and reduced in H₂ flow. Investigation of the three catalysts, (RHS-Ni)_R350, (RHS-Ni–A)_R350 and (RHS-Ni–PDA)_R350, confirmed good dispersion of Ni nanoparticles; all catalysts were amorphous. The BET surface areas increased in the order: (RHS-Ni)_R350 < (RHS-Ni–A)_R350 < (RHS-Ni–PDA)_R350 with controlled pore sizes. The as-prepared catalysts were applied for both hydroconversion of cyclohexene with molecular H₂ and ethanol dehydrogenation, using a flow-type reactor, at different temperatures. The activity in cyclohexene hydroconversion and selectivity to cyclohexane depended upon the reaction temperature; at t < 150 °C, the increased hydrogenation activity was referred to the formed SiO₂–Ni–amine complex, pore regulation as a prime requirement for H₂ storage and homogeneous distribution of incorporated Ni nanoparticles. At t > 150 °C, the backward dehydrogenation pathway was more favored, due to unavailability of H₂; the process became structure-sensitive. In ethanol conversion, the prevailing dehydrogenation activity of organically modified catalyst samples was encouraged by improved homogeneous distribution of Ni nanoparticles and created micropre system.     

Effects of blackberry juice on growth inhibition of foodborne pathogens and growth promotion of Lactobacillus

Berries such as blueberry, blackberry and raspberry possess several biological activities including antimicrobial and nutritional effects. In this study, the antimicrobial activities of blackberry (Rubus fruticosus) juice against foodborne pathogens including Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli O157:H7 were investigated. Inhibition of growth of these foodborne pathogens was measured in broth (Luria–Bertani broth for E. coli O157:H7 and S. Typhimurium, and brain heart infusion broth for L. monocytogenes), skim milk and whole milk supplemented with 10% blackberry juice at different time points (0, 24, 48 and 72 h). The effects of blackberry juice on the growth of Lactobacillus casei, Lactobacillus plantarum and Lactobacillus rhamnosus were also investigated in Man–Rogosa–Sharpe (MRS) broth and skim and whole milk supplemented with blackberry juice. The growth of L. monocytogenes, S. Typhimurium and E. coli O157:H7 were significantly inhibited by blackberry juice by 1–3 logs in both milk and broth. We also observed that the growths of Lactobacillus strains were significantly stimulated (1–4 logs CFU/mL) by blackberry juice in both milk and MRS broth. These data clearly demonstrate that diluted blackberry juice can be used as a preservative in food processing and a preventive in foodborne infections as a natural antimicrobial.     

Kinetic Modeling of Hydrodenitrogenation of Pyridine

Abstract

This study is aimed at developing a kinetic model for the hydrodenitrogenation (HDN) of pyridine. The developed model deals with the selectivity of piperidine, one of the products obtained from the HDN of pyridine and with the conversion of pyridine to piperidine. Kinetic parameters were estimated from the results of the experimental data obtained from literature sources where the reactions were carried out in a trickle-bed reactor in the liquid phase over Mo₂C, NbMo₂C, and MoS₂/SiO₂ catalysts at temperatures of 480 to 590 K. POLYMATH 5.0 software was used to solve the proposed first-order model. It was shown that during the course of the HDN reaction of pyridine the conversion increases exponentially with temperature while selectivity of piperidine with respect to pyridine decreases with temperature. The changes in activation energies evaluated for the catalysts were 80.30 kJ/mol, 55.10 kJ/mol, and 40.85 kJ/mol for Mo₂C, NbMo₂C, and MoS₂/SiO₂, respectively.