Reverse micellar extraction of amino acids and complex enzyme mixtures

In this work, the reverse micellar extraction with the anionic surfactant dioctyl sodium sulfosuccinate (AOT) in isooctane for the extraction of biomolecules is investigated. The forward (FE) and backward extraction (BE) of amino acids and mixtures of these as well as the application for complex enzyme mixtures like Celluclast 1.5L and Novozyme 188 are presented. The selective separation of the mixtures of amino acids (Mix1: Asparagine, aspartic acid and arginine, Mix2: Glutamine, glutaminic acid and histidine) are presented. The efficiency in mixtures of amino acids is lower in comparison to pure amino acids, where no interaction occurs at corresponding process conditions. The experimental results are compared to predictions based on the thermodynamic model COSMO-RS. This is the first time that the partition behavior of various amino acids at different ionization states is predicted in this way. The selected enzyme mixtures Celluclast 1.5L and Novozyme 188 are relevant for the conversion of biomass to bioethanol in biorefineries. Therefore an extraction and recycling of these enzymes during the process can be economically beneficial. The focus lies on the investigation of different influencing parameters like salt concentration (ionic strength) and pH of the aqueous phase in order to retrieve a high selectivity and high activity of the enzymes. At a pH lower than the pI of the proteins the highest extraction is observed and the activity of the enzymes has been maintained to at least 80% with respect to the maximum activity. The applicability of the reverse micellar extraction for these systems has therefore successfully been demonstrated. However, improvements in terms of back extraction are needed.

Subjects

β-Glucosidase

AOT

Cellulase

COSMO-RS

COSMOmic

Reverse micellar extraction

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Reverse micellar extraction of amino acids and complex enzyme mixtures