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Evaluation of an adsorbent based on agricultural waste (corn cobs) for removal of tyrosine and phenylalanine from aqueous solutions.

Alves CC, Franca AS, Oliveira LS - Biomed Res Int (2013)

Bottom Line: Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the production of protein hydrolysates used as dietary formulations for patients suffering from congenital disorders of amino acid metabolism, such as phenylketonuria.In this study, an adsorbent prepared from corn cobs was evaluated for the removal of tyrosine (Tyr) from both a single component solution and a binary aqueous solution with phenylalanine (Phe).Such results indicate that, in binary systems, Phe will be adsorbed preferably to Tyr, and this is a welcome feature when employing the prepared adsorbent for the removal of Phe from protein hydrolysates to be used in dietary formulations for phenylketonuria treatment.

View Article: PubMed Central - PubMed

Affiliation: PPGCA/Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.

ABSTRACT
Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the production of protein hydrolysates used as dietary formulations for patients suffering from congenital disorders of amino acid metabolism, such as phenylketonuria. In this study, an adsorbent prepared from corn cobs was evaluated for the removal of tyrosine (Tyr) from both a single component solution and a binary aqueous solution with phenylalanine (Phe). The adsorption behavior of tyrosine was similar to that of phenylalanine in single component solutions, however, with a much lower adsorption capacity (14 mg g(-1) for Tyr compared to 109 mg g(-1) for Phe). Tyr adsorption kinetics was satisfactorily described by a pseudosecond-order model as it was for Phe. In adsorption equilibrium studies for binary mixtures, the presence of Tyr in Phe solutions favored Phe faster adsorption whereas the opposite behavior was observed for the presence of Phe in Tyr solutions. Such results indicate that, in binary systems, Phe will be adsorbed preferably to Tyr, and this is a welcome feature when employing the prepared adsorbent for the removal of Phe from protein hydrolysates to be used in dietary formulations for phenylketonuria treatment.

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Adsorption isotherms obtained for Tyr removal (■: 25°C; ▲: 35°C; ●: 45°C); solid lines represent Langmuir-Freundlich fits.
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fig4: Adsorption isotherms obtained for Tyr removal (■: 25°C; ▲: 35°C; ●: 45°C); solid lines represent Langmuir-Freundlich fits.

Mentions: The adsorption isotherms for removal of pure Tyr at 25, 35, and 45°C are displayed in Figure 4. The shapes of the curves are characteristic of favorable adsorption, regardless of temperature being similar to the curves obtained for Phe removal [10]. An evaluation of isotherms presented in Figure 4 indicates that Tyr removal is an exothermic process, since increases in temperature led to decreases in the amount adsorbed, as previously reported for Phe [10]. Such behavior can be attributed to the hydrophobic nature of aromatic aminoacids such as Tyr and Phe. As the temperature increases, these aminoacids present greater tendency to form hydrophobic bonds in solution as opposed to interacting with the adsorbent surface [18].


Evaluation of an adsorbent based on agricultural waste (corn cobs) for removal of tyrosine and phenylalanine from aqueous solutions.

Alves CC, Franca AS, Oliveira LS - Biomed Res Int (2013)

Adsorption isotherms obtained for Tyr removal (■: 25°C; ▲: 35°C; ●: 45°C); solid lines represent Langmuir-Freundlich fits.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3713363&req=5

fig4: Adsorption isotherms obtained for Tyr removal (■: 25°C; ▲: 35°C; ●: 45°C); solid lines represent Langmuir-Freundlich fits.
Mentions: The adsorption isotherms for removal of pure Tyr at 25, 35, and 45°C are displayed in Figure 4. The shapes of the curves are characteristic of favorable adsorption, regardless of temperature being similar to the curves obtained for Phe removal [10]. An evaluation of isotherms presented in Figure 4 indicates that Tyr removal is an exothermic process, since increases in temperature led to decreases in the amount adsorbed, as previously reported for Phe [10]. Such behavior can be attributed to the hydrophobic nature of aromatic aminoacids such as Tyr and Phe. As the temperature increases, these aminoacids present greater tendency to form hydrophobic bonds in solution as opposed to interacting with the adsorbent surface [18].

Bottom Line: Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the production of protein hydrolysates used as dietary formulations for patients suffering from congenital disorders of amino acid metabolism, such as phenylketonuria.In this study, an adsorbent prepared from corn cobs was evaluated for the removal of tyrosine (Tyr) from both a single component solution and a binary aqueous solution with phenylalanine (Phe).Such results indicate that, in binary systems, Phe will be adsorbed preferably to Tyr, and this is a welcome feature when employing the prepared adsorbent for the removal of Phe from protein hydrolysates to be used in dietary formulations for phenylketonuria treatment.

View Article: PubMed Central - PubMed

Affiliation: PPGCA/Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.

ABSTRACT
Adsorption of phenolic amino acids, such as phenylalanine and tyrosine, is quite relevant for the production of protein hydrolysates used as dietary formulations for patients suffering from congenital disorders of amino acid metabolism, such as phenylketonuria. In this study, an adsorbent prepared from corn cobs was evaluated for the removal of tyrosine (Tyr) from both a single component solution and a binary aqueous solution with phenylalanine (Phe). The adsorption behavior of tyrosine was similar to that of phenylalanine in single component solutions, however, with a much lower adsorption capacity (14 mg g(-1) for Tyr compared to 109 mg g(-1) for Phe). Tyr adsorption kinetics was satisfactorily described by a pseudosecond-order model as it was for Phe. In adsorption equilibrium studies for binary mixtures, the presence of Tyr in Phe solutions favored Phe faster adsorption whereas the opposite behavior was observed for the presence of Phe in Tyr solutions. Such results indicate that, in binary systems, Phe will be adsorbed preferably to Tyr, and this is a welcome feature when employing the prepared adsorbent for the removal of Phe from protein hydrolysates to be used in dietary formulations for phenylketonuria treatment.

Show MeSH
Related in: MedlinePlus