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M H Zwietering - One of the best experts on this subject based on the ideXlab platform.

  • model for the combined effects of temperature ph and sodium lactate on growth rates of listeria innocua in broth and bologna type sausages
    Applied and Environmental Microbiology, 1996
    Co-Authors: P C Houtsma, M L T Kantmuermans, F M Rombouts, M H Zwietering
    Abstract:

    A modified Monod Equation was successfully applied in describe the maximum specific growth rate of Listeria innocua in a broth model in the presence of various concentrations of sodium lactate or NaCl. The combined effects of temperature and pH were assessed by translating the parameters of the modified Monod Equation ({m), α, and p') as functions of pH and/or temperature. As a result, the area in which the growth rate could be predicted was extended to include as a variable not only the salt concentration but also pH and temperature. The number of parameters needed to describe the experimental data was thereby reduced from 48 to 4 (NaCl) and from 42 to 5 (sodium lactate). The decline in the goodness of fit that accompanied the reduction in the number of parameters was within statistically acceptable ranges. The resulting model was compared with a polynomial fit, and it was proposed that the former was more suitable for the purpose of this study. The broth model for sodium lactate was evaluated with Bologna-type sausages. Because of the 'worst-case' design of the broth model, it was necessary to reestimate one or all parameters to obtain a good description of the growth rate of L. innocua in the meat product. However, the simplicity of the model and the practical usefulness of its parameters offer considerable prospects for its use in predictive microbiology. Chemicals/CAS: Lactates; Lactic Acid, 50-21-5

  • Model for the combined effects of temperature, pH, and sodium lactate on growth rates of Listeria innocua in broth and Bologna-type sausages.
    Applied and environmental microbiology, 1996
    Co-Authors: P C Houtsma, F M Rombouts, M.l.t. Kant-muermans, M H Zwietering
    Abstract:

    A modified Monod Equation was successfully applied to describe the maximum specific growth rate of Listeria innocua in a broth model in the presence of various concentrations of sodium lactate or NaCl. The combined effects of temperature and pH were assessed by translating the parameters of the modified Monod Equation mu(m), alpha, and p') as functions of pH and/or temperature. As a result, the area in which the growth rate could be predicted was extended to include as a variable not only the salt concentration but also pH and temperature. The number of parameters needed to describe the experimental data was thereby reduced from 48 to 4 (NaCl) and from 42 to 5 (sodium lactate). The decline in the goodness of fit that accompanied the reduction in the number of parameters was within statistically acceptable ranges. The resulting model was compared with a polynomial fit, and it was proposed that the former was more suitable for the purpose of this study. The broth model for sodium lactate was evaluated with Bologna-type sausages. Because of the "worst-case" design of the broth model, it was necessary to reestimate one or all parameters to obtain a good description of the growth rate of L. innocua in the meat product. However, the simplicity of the model and the practical usefulness of its parameters offer considerable prospects for its use in predictive microbiology.

Yu Liu - One of the best experts on this subject based on the ideXlab platform.

  • Overview of some theoretical approaches for derivation of the Monod Equation
    Applied Microbiology and Biotechnology, 2007
    Co-Authors: Yu Liu
    Abstract:

    The Monod Equation has been widely applied to describe microbial growth, but it has no mechanistic basis and is purely empirical. Extensive efforts have been dedicated to develop theoretical approaches for derivation of the Monod Equation, which can be classified into three major groups, i.e., kinetic, thermodynamic, and substance transport approaches. In this review, four representative approaches are thus discussed. Due to the fact that different assumptions are made in each approach, no universal physical meaning of the Monod constant ( K _s) can be revealed. However, it seems that the Monod constant would be free energy-dependent and have nonequilibrium thermodynamic characteristics.

  • A simple thermodynamic approach for derivation of a general Monod Equation for microbial growth
    Biochemical Engineering Journal, 2006
    Co-Authors: Yu Liu
    Abstract:

    Abstract The Monod Equation has been widely applied to describe microbial growth, but it has no any mechanistic basis. Based on the thermodynamics of microbial growth process, a general model for microbial growth was developed. The constants involved in the present model were defined with clear physical meanings. The model derived can be reduced to the Monod Equation, Grau Equation and Hill or Moser Equation. Compared to the Michaelis–Menten constant with the equilibrium thermodynamic characteristics, it was shown that the Monod constant ( K s ) has non-equilibrium thermodynamic characteristics.

  • A thermodynamic interpretation of the Monod Equation.
    Current microbiology, 2003
    Co-Authors: Yu Liu, Yue-mei Lin, Shu-fang Yang
    Abstract:

    The Monod Equation for microbial growth is purely empirical, and the theoretical basis of this model stays unclear. Similar to any chemical reactions, overall microbial growth process is dependent upon the changes in free energy. This study showed that the Monod Equation could be interpreted in a thermodynamic sense very well. It was probably for the first time demonstrated that the Monod constant (K s ) was inversely related to the equilibrium constant of the overall microbial growth process.

P C Houtsma - One of the best experts on this subject based on the ideXlab platform.

  • model for the combined effects of temperature ph and sodium lactate on growth rates of listeria innocua in broth and bologna type sausages
    Applied and Environmental Microbiology, 1996
    Co-Authors: P C Houtsma, M L T Kantmuermans, F M Rombouts, M H Zwietering
    Abstract:

    A modified Monod Equation was successfully applied in describe the maximum specific growth rate of Listeria innocua in a broth model in the presence of various concentrations of sodium lactate or NaCl. The combined effects of temperature and pH were assessed by translating the parameters of the modified Monod Equation ({m), α, and p') as functions of pH and/or temperature. As a result, the area in which the growth rate could be predicted was extended to include as a variable not only the salt concentration but also pH and temperature. The number of parameters needed to describe the experimental data was thereby reduced from 48 to 4 (NaCl) and from 42 to 5 (sodium lactate). The decline in the goodness of fit that accompanied the reduction in the number of parameters was within statistically acceptable ranges. The resulting model was compared with a polynomial fit, and it was proposed that the former was more suitable for the purpose of this study. The broth model for sodium lactate was evaluated with Bologna-type sausages. Because of the 'worst-case' design of the broth model, it was necessary to reestimate one or all parameters to obtain a good description of the growth rate of L. innocua in the meat product. However, the simplicity of the model and the practical usefulness of its parameters offer considerable prospects for its use in predictive microbiology. Chemicals/CAS: Lactates; Lactic Acid, 50-21-5

  • Model for the combined effects of temperature, pH, and sodium lactate on growth rates of Listeria innocua in broth and Bologna-type sausages.
    Applied and environmental microbiology, 1996
    Co-Authors: P C Houtsma, F M Rombouts, M.l.t. Kant-muermans, M H Zwietering
    Abstract:

    A modified Monod Equation was successfully applied to describe the maximum specific growth rate of Listeria innocua in a broth model in the presence of various concentrations of sodium lactate or NaCl. The combined effects of temperature and pH were assessed by translating the parameters of the modified Monod Equation mu(m), alpha, and p') as functions of pH and/or temperature. As a result, the area in which the growth rate could be predicted was extended to include as a variable not only the salt concentration but also pH and temperature. The number of parameters needed to describe the experimental data was thereby reduced from 48 to 4 (NaCl) and from 42 to 5 (sodium lactate). The decline in the goodness of fit that accompanied the reduction in the number of parameters was within statistically acceptable ranges. The resulting model was compared with a polynomial fit, and it was proposed that the former was more suitable for the purpose of this study. The broth model for sodium lactate was evaluated with Bologna-type sausages. Because of the "worst-case" design of the broth model, it was necessary to reestimate one or all parameters to obtain a good description of the growth rate of L. innocua in the meat product. However, the simplicity of the model and the practical usefulness of its parameters offer considerable prospects for its use in predictive microbiology.

F M Rombouts - One of the best experts on this subject based on the ideXlab platform.

  • model for the combined effects of temperature ph and sodium lactate on growth rates of listeria innocua in broth and bologna type sausages
    Applied and Environmental Microbiology, 1996
    Co-Authors: P C Houtsma, M L T Kantmuermans, F M Rombouts, M H Zwietering
    Abstract:

    A modified Monod Equation was successfully applied in describe the maximum specific growth rate of Listeria innocua in a broth model in the presence of various concentrations of sodium lactate or NaCl. The combined effects of temperature and pH were assessed by translating the parameters of the modified Monod Equation ({m), α, and p') as functions of pH and/or temperature. As a result, the area in which the growth rate could be predicted was extended to include as a variable not only the salt concentration but also pH and temperature. The number of parameters needed to describe the experimental data was thereby reduced from 48 to 4 (NaCl) and from 42 to 5 (sodium lactate). The decline in the goodness of fit that accompanied the reduction in the number of parameters was within statistically acceptable ranges. The resulting model was compared with a polynomial fit, and it was proposed that the former was more suitable for the purpose of this study. The broth model for sodium lactate was evaluated with Bologna-type sausages. Because of the 'worst-case' design of the broth model, it was necessary to reestimate one or all parameters to obtain a good description of the growth rate of L. innocua in the meat product. However, the simplicity of the model and the practical usefulness of its parameters offer considerable prospects for its use in predictive microbiology. Chemicals/CAS: Lactates; Lactic Acid, 50-21-5

  • Model for the combined effects of temperature, pH, and sodium lactate on growth rates of Listeria innocua in broth and Bologna-type sausages.
    Applied and environmental microbiology, 1996
    Co-Authors: P C Houtsma, F M Rombouts, M.l.t. Kant-muermans, M H Zwietering
    Abstract:

    A modified Monod Equation was successfully applied to describe the maximum specific growth rate of Listeria innocua in a broth model in the presence of various concentrations of sodium lactate or NaCl. The combined effects of temperature and pH were assessed by translating the parameters of the modified Monod Equation mu(m), alpha, and p') as functions of pH and/or temperature. As a result, the area in which the growth rate could be predicted was extended to include as a variable not only the salt concentration but also pH and temperature. The number of parameters needed to describe the experimental data was thereby reduced from 48 to 4 (NaCl) and from 42 to 5 (sodium lactate). The decline in the goodness of fit that accompanied the reduction in the number of parameters was within statistically acceptable ranges. The resulting model was compared with a polynomial fit, and it was proposed that the former was more suitable for the purpose of this study. The broth model for sodium lactate was evaluated with Bologna-type sausages. Because of the "worst-case" design of the broth model, it was necessary to reestimate one or all parameters to obtain a good description of the growth rate of L. innocua in the meat product. However, the simplicity of the model and the practical usefulness of its parameters offer considerable prospects for its use in predictive microbiology.

Seteno Ko Ntwampe - One of the best experts on this subject based on the ideXlab platform.

  • Kinetic modelling of cell growth, substrate utilization, and biosurfactant production from solid agrowaste (Beta vulgaris) by Bacillus licheniformis STK 01
    The Canadian Journal of Chemical Engineering, 2016
    Co-Authors: Olusola Solomon Amodu, Tunde Victor Ojumu, Seteno Ko Ntwampe
    Abstract:

    The kinetics of cell growth, substrate utilization, and biosurfactant production by Bacillus licheniformis STK 01 from a solid agrowaste substrate (Beta vulgaris) and a refined substrate (mineral salts, MS) was investigated. Data obtained were fitted to the integrated Monod Equation, logistic models, and Leudeking–Piret model using nonlinear regression analyses. The maximum cell growth was observed after 72 h of fermentation for both substrates. The highest biosurfactant production was 5.8 ± 0.5 g/L when the B. vulgaris waste substrate was used, while the production increased up to 9.78 ± 1.02 g/L when MS was used. The biosurfactant produced from B. vulgaris and MS lowered the surface tension of the broth to 30 and 23.5 mN/m respectively. Furthermore, from the kinetic data analyses, cell growth and B. vulgaris utilization were described by the logistic model and modified Monod Equation, respectively, with the maximum cell growth rate of 0.026 h−1, cell yield of 0.617, and the Monod saturation constant being 0.418 g/L. Similarly, biosurfactant production was best described by the logistic model while the production rate constant was 0.140 h−1. This study is applicable, among other areas, in the design of biological systems augmented with B. vulgaris waste.

  • Kinetic modeling of cell growth, substrate utilization, and biosurfactant production from solid agrowaste (Beta vulgaris) by Bacillus licheniformis STK 01
    The Canadian Journal of Chemical Engineering, 2016
    Co-Authors: Amodu, Olusola Solomon, Tunde Victor Ojumu, Seteno Ko Ntwampe
    Abstract:

    The kinetics of cell growth, substrate utilization and biosurfactant production by Bacillus licheniformis STK 01 from a solid agrowaste substrate (Beta vulgaris) and a refined substrate (mineral salts, MS) was investigated. Data obtained were fitted to the integrated Monod Equation, logistic models, and Leudeking–Piret model using nonlinear regression analyses. The maximum cell growth was observed after 72 h of fermentation for both substrates. The highest biosurfactant production was 5.8 ± 0.5 g/L when the B. vulgaris waste substrate was used, while the production increased up to 9.78 ± 1.02 g/L when MS was used. The biosurfactant produced from B. vulgaris and MS lowered the surface tension of the broth to 30 and 23.5 mN/m respectively. Furthermore, from the kinetic data analyses, cell growth and B. vulgaris utilization were described by the logistic model and modified Monod Equation, respectively, with the maximum cell growth rate of 0.026 h−1, cell yield of 0.617, and the Monod saturation constant being 0.418 g/L. Similarly, biosurfactant production was best described by the logistic model while the production rate constant was 0.140 h−1. This study is applicable, among other areas, in the design of biological systems augmented with B. vulgaris waste.Cape Peninsula Universityof Technology through the University Research Fund (URF