Simultaneous and selective decarboxylation of l-serine and deamination of l-phenylalanine in an amino acid mixture—a means of separating amino acids for synthesizing biobased chemicals
Teng, Y. ; Scott, E.L. ; Witte-van Dijk, S.C.M. ; Sanders, J.P.M. - \ 2016
New Biotechnology 33 (2016)1. - ISSN 1871-6784 - p. 171 - 178.
Amino acids (AAs) obtained from the hydrolysis of biomass-derived proteins are interesting feedstocks for the chemical industry. They can be prepared from the byproduct of biofuel production and agricultural wastes. They are rich in functionalities needed in petrochemicals, providing the opportunity to save energy, reagents, and process steps. However, their separation is required before they can be applied for further applications. Electrodialysis (ED) is a promising separation method, but its efficiency needs to be improved when separating AAs with similar isoelectric points. Thus, specific conversions are required to form product with different charges. Here we studied the enzymatic conversions which can be used as a means to aid the ED separation of neutral AAs. A model mixture containing l-serine, l-phenylalanine and l-methionine was used. The reactions of l-serine decarboxylase and l-phenylalanine ammonia-lyase were employed to specifically convert serine and phenylalanine into ethanolamine and trans-cinnamic acid. At the isoelectric point of methionine (pH 5.74), the charge of ethanolamine and trans-cinnamic acid are +1 and –1, therefore facilitating potential separation into three different streams by electrodialysis. Here the enzyme kinetics, specificity, inhibition and the operational stabilities were studied, showing that both enzymes can be applied simultaneously to aid the ED separation of neutral AAs.
The selective conversion of glutamic acid in amino acid mixtures using glutamate decarboxylase—A means of separating amino acids for synthesizing biobased chemicals
Teng, Y. ; Scott, E.L. ; Sanders, J.P.M. - \ 2014
Biotechnology Progress 30 (2014)3. - ISSN 8756-7938 - p. 681 - 688.
nitrogen-containing chemicals - bulk chemicals - electrodialysis - biorefinery - biomass - immobilization - chromatography - alginate
Amino acids (AAs) derived from hydrolysis of protein rest streams are interesting feedstocks for the chemical industry due to their functionality. However, separation of AAs is required before they can be used for further applications. Electrodialysis may be applied to separate AAs, but its efficiency is limited when separating AAs with similar isoelectric points. To aid the separation, specific conversion of an AA to a useful product with different charge behavior to the remaining compounds is desired. Here the separation of L-aspartic acid (Asp) and L-glutamic acid (Glu) was studied. L-Glutamate a-decarboxylase (GAD, Type I, EC 22.214.171.124) was applied to specifically convert Glu into c-aminobutyric acid (GABA). GABA has a different charge behavior from Asp therefore allowing a potential separation by electrodialysis. Competitive inhibition and reduced operational stability caused by Asp could be eliminated by maintaining a sufficiently high concentration of Glu. Immobilization of GAD does not reduce the enzyme’s initial activity. However, the operational stability was slightly reduced. An initial study on the reaction operating in a continuous mode was performed using a column reactor packed with immobilized GAD. As the reaction mixture was only passed once through the reactor, the conversion of Glu was lower than expected. To complete the conversion of Glu, the stream containing Asp and unreacted Glu might be recirculated back to the reactor after GABA has been removed. Overall, the reaction by GAD is specific to Glu and can be applied to aid the electrodialysis separation of Asp and Glu.
Specific conversion of amino acids as a means for their separation
Teng, Y. - \ 2014
Wageningen University. Promotor(en): Johan Sanders, co-promotor(en): Elinor Scott. - Wageningen : Wageningen University - ISBN 9789462570658 - 205
aminozuren - scheiding - elektrodialyse - conversie - chemicaliën uit biologische grondstoffen - onderzoek - biobased economy - amino acids - separation - electrodialysis - conversion - biobased chemicals - research - biobased economy
Aminozuren (AZ) zijn interessante uitgangspunten voor stikstofhoudende (amine) chemicaliën. Zij kunnen gewonnen worden als mengsel uit de hydrolyse van potentieel goedkope eiwitten verkregen van de bijproducten van de biobrandstofproductie of agrarische en voedselafvalstromen. Echter, AZ verkregen van zulke bronnen bevinden zich in een mengsel. Hierdoor is een scheiding nodig om de individuele AZ te verkrijgen voor vervolgomzettingen en toepassingen. Electrodialyse (ED) is een veelbelovende scheidingsmethode die toegepast kan worden in continue modus en op grote schaal.
Separation of L-aspartic acid and L-glutamic acid mixtures for use in the production of bio-based chemicals
Teng, Y. ; Scott, E.L. ; Sanders, J.P.M. - \ 2012
Journal of Chemical Technology and Biotechnology 87 (2012)10. - ISSN 0268-2575 - p. 1458 - 1465.
nitrogen-containing chemicals - amino-acids - biobased production - derivatives - hydrolysis - proteins - kinetics
BACKGROUND: Amino acids are promising feedstocks for the chemical industry due to their chemical functionality. They can be obtained by the hydrolysis of potentially inexpensive protein streams such as the byproduct of biofuel production. However, individual amino acids are required before they can be used for the further production of chemicals. Here, the separation of L-aspartic acid (Asp) and L-glutamic acid (Glu) mixture, which can be isolated from protein hydrolysis solutions at low pH or from electrodialysis of complex amino acid mixtures, was studied. RESULTS: Glu was converted into L-pyroglutamic acid (pGlu) which can be separated from the mixture of Asp and Glu due to its higher solubility in water. The conversion was carried out under aqueous or melt conditions. Under aqueous conditions, the conversion was studied as a factor of time, temperature and the amount of Glu. The conversion was specific with high yield and not effected by Asp. After pGlu was separated from Asp and residual Glu by solubility difference, it can be transferred back to Glu through hydrolysis. CONCLUSION: The conversion of Glu to pGlu is specific and can be applied to separation Asp and Glu for their use in the production of bio-based chemicals
The use of L-lysine decarboxylase as a means to separate amino acids by electrodialysis
Teng, Y. ; Scott, E.L. ; Zeeland, A.N.T. van; Sanders, J.P.M. - \ 2011
Green Chemistry 13 (2011)3. - ISSN 1463-9262 - p. 624 - 630.
nitrogen-containing chemicals - biobased production - enzyme electrode - bulk chemicals - immobilization - alginate - biomass
Amino acids (AA's) are interesting materials as feedstocks for the chemical industry as they contain chemical functionalities similar to conventional petrochemicals. This offers the possibility to circumvent process steps, energy and reagents. AA's can be obtained by the hydrolysis of potentially inexpensive voluminous protein streams derived from biofuel production. However, isolation of the preferred AA is required in order to carry out further transformation into the desired product. Theoretically separation may be achieved using electrodialysis. To increase efficiency, specific modification to a product of industrial interest and removes charged groups of AA's with similar isoelectric points is required. Here, the reaction of L-lysine decarboxylase (LDC) was studied as a means to specifically convert L-lysine (Lys) to 1,5-pentanediamine (PDA) in the presence of L-arginine (Arg) to produce products with different charge thus allowing isolation of products by electrodialysis. Immobilization of LDC in calcium alginate enhanced the operational stability and conversion in mixtures of amino acids was highly specific. At 30 °C the presence of Arg had little effect on the activity of the enzyme although inhibition by the product PDA could be observed. Volumetric productivity was calculated and raw material and transformation costs were estimated for a potential process using a mixture of Arg and Lys.