The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Seteno Ko Ntwampe - One of the best experts on this subject based on the ideXlab platform.
-
influence of perfluorocarbons on phanerochaete chrysosporium biomass development Substrate Consumption and enzyme production
Chemical and Biochemical Engineering Quarterly, 2010Co-Authors: Seteno Ko Ntwampe, C C Williams, Marshall Sheerene SheldonAbstract:Limitations placed on aerobic cultures by dissolved oxygen can be alleviated by using oxygen-vectors such as perfluorinated organic oils. In this study, Phanerochaete chrysosporium was tested in batch cultures to evaluate the efficacy of perfluorinated oils in improving biomass development, nutrient Consumption and extracellular enzyme production. The oils used in an emulsified form in this study were perfluorotripropylamine, perfluorooctyl bromide and bis-(perfluorobutyl) ethene, as they dissolve higher quantities of oxygen compared to others. The surfactant used to stabilise the emulsion was Pluronic F 68, which was used at a concentration of 8.5 % (w/v). The addition of only the surfactant to the medium resulted in a 6.9-fold increase (1.38 mg mL –1 )i n biomass concentration of P. chrysosporium, while a biomass concentration of 0.82 to 1.53 mg mL –1 (4.1 to 7.6-fold increase) was observed in the PFC emulsions with an oil-phase fraction in the range of 0.1 to 0.3 (w/v), i.e. 10 to 30 % (w/v). The highest enzyme activity from crude samples was 307 and 410 U L –1 for LiP and MnP, respectively, compared to <100 and <50 U L –1 enzyme activity for LiP and MnP obtained in control cultures, respectively. Ammonium and glucose utilisation was higher in emulsions with PFC concentrations of 10 % (w/v) for all the perfluorocarbons evaluated than at concentrations of 20 % and 30 % (w/v). It was concluded that the use of the perfluorocarbon emulsions improved the performance of P. chrysosporium BKMF 1767 in terms of biomass development, nutrient Consumption and enzyme production. Furthermore, PF 68 was found to have growth-promoting abilities for P. chrysosporium.
-
quantifying growth kinetics of phanerochaete chrysosporium immobilised on a vertically orientated polysulphone capillary membrane biofilm development and Substrate Consumption
Biochemical Engineering Journal, 2006Co-Authors: Seteno Ko Ntwampe, M S SheldonAbstract:Abstract Growth kinetics is one of the most important and critical parameters for studying biofilms as they can be used to model mass transfer and biological reactions. Growth parameters of Phanerochaete chrysosporium were quantified based on the utilisation rate of glucose and biofilm generated in single fibre capillary membrane bioreactors (SFCMBR) operated vertically at 37 °C for 264 h. The growth rate constant value of 0.0348 h−1 was used to model the dry biofilm density profile, which was also classified as equivalent to the specific growth rate. The mass of glucose consumed, increased from 0.051 g/day during the lag phase, to 0.145 g/day in the secondary growth phase. An average glucose Consumption rate of 94.0 g/m3 h was determined over the period of 264 h. The average glucose-based growth yield coefficient of approximately 0.202 g biofilm/g glucose was determined. The primary growth phase reached a structural equilibrium (steady state) at an average density of 9.7E05 g/m3 in the period 168–216 h, with the secondary growth phase occurring after 216 h. The glucose maintenance coefficient value of 0.028 h−1, was obtained during the biofilm structural equilibrium phase.
-
quantifying growth kinetics of phanerochaete chrysosporium immobilised on a vertically orientated polysulphone capillary membrane biofilm development and Substrate Consumption
Biochemical Engineering Journal, 2006Co-Authors: Seteno Ko Ntwampe, Marshall Sheerene SheldonAbstract:Abstract Growth kinetics is one of the most important and critical parameters for studying biofilms as they can be used to model mass transfer and biological reactions. Growth parameters of Phanerochaete chrysosporium were quantified based on the utilisation rate of glucose and biofilm generated in single fibre capillary membrane bioreactors (SFCMBR) operated vertically at 37 °C for 264 h. The growth rate constant value of 0.0348 h−1 was used to model the dry biofilm density profile, which was also classified as equivalent to the specific growth rate. The mass of glucose consumed, increased from 0.051 g/day during the lag phase, to 0.145 g/day in the secondary growth phase. An average glucose Consumption rate of 94.0 g/m3 h was determined over the period of 264 h. The average glucose-based growth yield coefficient of approximately 0.202 g biofilm/g glucose was determined. The primary growth phase reached a structural equilibrium (steady state) at an average density of 9.7E05 g/m3 in the period 168–216 h, with the secondary growth phase occurring after 216 h. The glucose maintenance coefficient value of 0.028 h−1, was obtained during the biofilm structural equilibrium phase.
Marshall Sheerene Sheldon - One of the best experts on this subject based on the ideXlab platform.
-
influence of perfluorocarbons on phanerochaete chrysosporium biomass development Substrate Consumption and enzyme production
Chemical and Biochemical Engineering Quarterly, 2010Co-Authors: Seteno Ko Ntwampe, C C Williams, Marshall Sheerene SheldonAbstract:Limitations placed on aerobic cultures by dissolved oxygen can be alleviated by using oxygen-vectors such as perfluorinated organic oils. In this study, Phanerochaete chrysosporium was tested in batch cultures to evaluate the efficacy of perfluorinated oils in improving biomass development, nutrient Consumption and extracellular enzyme production. The oils used in an emulsified form in this study were perfluorotripropylamine, perfluorooctyl bromide and bis-(perfluorobutyl) ethene, as they dissolve higher quantities of oxygen compared to others. The surfactant used to stabilise the emulsion was Pluronic F 68, which was used at a concentration of 8.5 % (w/v). The addition of only the surfactant to the medium resulted in a 6.9-fold increase (1.38 mg mL –1 )i n biomass concentration of P. chrysosporium, while a biomass concentration of 0.82 to 1.53 mg mL –1 (4.1 to 7.6-fold increase) was observed in the PFC emulsions with an oil-phase fraction in the range of 0.1 to 0.3 (w/v), i.e. 10 to 30 % (w/v). The highest enzyme activity from crude samples was 307 and 410 U L –1 for LiP and MnP, respectively, compared to <100 and <50 U L –1 enzyme activity for LiP and MnP obtained in control cultures, respectively. Ammonium and glucose utilisation was higher in emulsions with PFC concentrations of 10 % (w/v) for all the perfluorocarbons evaluated than at concentrations of 20 % and 30 % (w/v). It was concluded that the use of the perfluorocarbon emulsions improved the performance of P. chrysosporium BKMF 1767 in terms of biomass development, nutrient Consumption and enzyme production. Furthermore, PF 68 was found to have growth-promoting abilities for P. chrysosporium.
-
quantifying growth kinetics of phanerochaete chrysosporium immobilised on a vertically orientated polysulphone capillary membrane biofilm development and Substrate Consumption
Biochemical Engineering Journal, 2006Co-Authors: Seteno Ko Ntwampe, Marshall Sheerene SheldonAbstract:Abstract Growth kinetics is one of the most important and critical parameters for studying biofilms as they can be used to model mass transfer and biological reactions. Growth parameters of Phanerochaete chrysosporium were quantified based on the utilisation rate of glucose and biofilm generated in single fibre capillary membrane bioreactors (SFCMBR) operated vertically at 37 °C for 264 h. The growth rate constant value of 0.0348 h−1 was used to model the dry biofilm density profile, which was also classified as equivalent to the specific growth rate. The mass of glucose consumed, increased from 0.051 g/day during the lag phase, to 0.145 g/day in the secondary growth phase. An average glucose Consumption rate of 94.0 g/m3 h was determined over the period of 264 h. The average glucose-based growth yield coefficient of approximately 0.202 g biofilm/g glucose was determined. The primary growth phase reached a structural equilibrium (steady state) at an average density of 9.7E05 g/m3 in the period 168–216 h, with the secondary growth phase occurring after 216 h. The glucose maintenance coefficient value of 0.028 h−1, was obtained during the biofilm structural equilibrium phase.
Jieshi Chen - One of the best experts on this subject based on the ideXlab platform.
-
the micro mechanism for the effect of sn grain orientation on Substrate Consumption in sn solder joints
Computational Materials Science, 2015Co-Authors: Jieshi ChenAbstract:Abstract The reliability of flip-chip M/Sn solder joint strongly depends on Sn grain orientation, since it affects the dissolution of metal pads and the growth of intermetallic compounds. In this paper, the micro-mechanism of the effect of Sn grain orientation on the diffusion of M atom (=Cu, Ni, Ag, Au or In) in Sn solder joints was investigated by employing the density functional theory. The adsorption energy of M atom on Sn(1 0 0) and (0 0 1) surfaces, the energy of M atom penetrating from the Sn surface to Sn body (penetration energy, E pe ) and the energy of M atom diffusing in the bulk Sn (diffusion energy) were analyzed, as well as the corresponding electronic structures for different steps. It is found that the M atoms were energetically favorable at the hollow sites of Sn(1 0 0) and (0 0 1) surfaces. Moreover, the adsorption energy of M/Sn(1 0 0) and M/Sn(0 0 1) were obtained. The M atom was more strongly adsorbed to Sn(0 0 1) than to Sn(1 0 0). The E pe for each M atom along a -axis of Sn grain was greater than the corresponding value that along c -axis. Moreover, the E pe increased gradually with the M atom changing from Ni to In. Electronic structure analysis shows that the E pe change can be attributed to three factors, including different atomic radius from Ni to In, difference in interatomic repulsive resistance between a and c -axis, and different hybrid orbitals between M 3 d and Sn 2 p from Ni to In. At last, the results show that M atoms could migrate easily in bulk Sn.
M S Sheldon - One of the best experts on this subject based on the ideXlab platform.
-
quantifying growth kinetics of phanerochaete chrysosporium immobilised on a vertically orientated polysulphone capillary membrane biofilm development and Substrate Consumption
Biochemical Engineering Journal, 2006Co-Authors: Seteno Ko Ntwampe, M S SheldonAbstract:Abstract Growth kinetics is one of the most important and critical parameters for studying biofilms as they can be used to model mass transfer and biological reactions. Growth parameters of Phanerochaete chrysosporium were quantified based on the utilisation rate of glucose and biofilm generated in single fibre capillary membrane bioreactors (SFCMBR) operated vertically at 37 °C for 264 h. The growth rate constant value of 0.0348 h−1 was used to model the dry biofilm density profile, which was also classified as equivalent to the specific growth rate. The mass of glucose consumed, increased from 0.051 g/day during the lag phase, to 0.145 g/day in the secondary growth phase. An average glucose Consumption rate of 94.0 g/m3 h was determined over the period of 264 h. The average glucose-based growth yield coefficient of approximately 0.202 g biofilm/g glucose was determined. The primary growth phase reached a structural equilibrium (steady state) at an average density of 9.7E05 g/m3 in the period 168–216 h, with the secondary growth phase occurring after 216 h. The glucose maintenance coefficient value of 0.028 h−1, was obtained during the biofilm structural equilibrium phase.
Yves Prigent - One of the best experts on this subject based on the ideXlab platform.
-
an unstructured model for the analysis of Substrate Consumption and product release in relation to biosynthesis and cell maintenance during batch cultures of geotrichum candidum and penicillium camembertii
Journal of Chemical Technology & Biotechnology, 2002Co-Authors: Lydia Adour, Abdeltif Amrane, C Couriol, Yves PrigentAbstract:An unstructured model has been developed to predict microbial growth based on carbon or nitrogen Substrate Consumption, ammonia or carbon dioxide production and proton transfer. The model has been validated for batch cultures of Geotrichum candidum and Penicillium camembertii growing on peptones and peptones + lactate based media. The contributions of the considered kinetics to biosynthesis and cellular maintenance can be deduced from this model. The nitrogen source (peptones) was mainly utilized in biosynthesis: for P camembertii growing on peptones, 86% of the metabolized peptones. G candidum metabolized peptones preferentially to lactate as a carbon source, resulting in lactate utilization by a maintenance mechanism during the stationary state. In contrast, P camembertii, which metabolized fewer amino acids as a carbon source, utilized lactate mainly for biosynthesis (83% of the consumed lactate). Most (up to 71%) of the ammonia released was produced by deamination of amino acids utilized as both carbon and nitrogen sources by growth-associated metabolism. With peptones, proton transfer resulted from ammonia release, most likely as a result of the growth-associated mechanism, as supported experimentally (55–58% of the released ammonia for both microorganisms). The contribution of lactate to proton transfer resulted in 76% of protons exchanged by a growth-associated mechanism during P camembertii growth. For total carbon dioxide production, the contributions of the energy supplies for biosynthesis and cell maintenance were similar; except during P camembertii growth in the presence of lactate (65% of growth-associated CO2 production). © 2002 Society of Chemical Industry
-
growth model of penicillium camembertii cultivated on a solid medium a logistic model for Substrate Consumption and metabolite production
Process Biochemistry, 2002Co-Authors: M Aldarf, Florence Fourcade, Abdeltif Amrane, Yves PrigentAbstract:Abstract Growth of Penicillium camembertii has been studied at the surface of a gelified medium. The Verlhust (or logistic) model has been tested and validated for the fitting of Substrates Consumption (lactate and peptone), ammonia production and proton transfer kinetics. With the obtained fitted parameters, the logistic model has been also applied to fit the growth kinetic by means of two additional parameters: the global yield and a parameter α which characterized the linking between growth and Substrate Consumption (or production). Instantaneous yield biomass on Substrate (or product) can be deduced from the model. The yields remained constant on the whole culture when there is a total linking between the Consumption (or production) and growth. It is almost the case for peptone Consumption, and then a low value for the parameter α is observed. The model also allowed a fine analysis of the different growth phases.
-
reconstruction of the biomass history from carbon and nitrogen Substrate Consumption ammonia release and proton transfer during solid cultures of geotrichum candidum and penicillium camembertii
Applied Microbiology and Biotechnology, 2002Co-Authors: M Aldarf, Abdeltif Amrane, Yves PrigentAbstract:Geotrichum candidum and Penicillium camembertii were cultivated on the surface of a gelified medium, simulating the composition of the aqueous phase of a Camembert cheese. The relation of their growth with Substrate Consumption (carbon or nitrogen), metabolite production (ammonia), or proton transfer (deduced from pH by means of the buffer capacity of the medium) was examined. The coefficients associated with cellular biosynthesis and resulting from cellular maintenance were determined. From these coefficients and the considered Substrate utilization or metabolite production kinetics, the growth kinetics were reconstructed until the end of growth. The model allowed analysis of biosynthesis and cellular maintenance contributions to the considered kinetics. At the end of growth, almost all the peptone was used for G. candidum biosynthesis, while most of the lactic acid (62%) was used for cellular maintenance. P. camembertii metabolized fewer amino acids as carbon sources, resulting in use of peptone for maintenance (12%), and lactic acid (80%) for cell biosynthesis. For both microorganisms, ammonia production was growth-associated, since this production resulted from the deamination of carbon- and nitrogen-source amino acids, in close relation with peptone Consumption.
