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Bioconversion of phenylpyruvic acid to l-phenylalanine by mixed-gel immobilization of Escherichia coli EP8-10

Paper ID Volume ID Publish Year Pages File Format Full-Text
35225 45082 2009 4 PDF Available
Title
Bioconversion of phenylpyruvic acid to l-phenylalanine by mixed-gel immobilization of Escherichia coli EP8-10
Abstract

A mixed-gel of κ-carrageenan and gelatin was used in l-phenylalanine production. The mixed-gel, containing 87.5% κ-carrageenan and 12.5% gelatin [the total gel concentration was 4 wt%], showed the best performance and was selected for further study with Escherichia coli EP8-10. The optimum pH and temperature were 8.5 and 37 °C, respectively. The effects of trehalose and Mg2+ were studied in the mixed-gel immobilization. Their optimum concentrations were 5 × 10−2 and 2 × 10−3 mol/L, respectively. Under the optimal conditions, 98.3% of the phenylpyruvic acid (PPA) was converted to l-phenylalanine. The activity recovery of the transaminase enzyme in the mixed-gel immobilization was higher than that in single κ-carrageenan immobilization, which was 93.6%. The total PPA conversion rate was over 80% in all 15 batches, suggesting great sustainability in the mixed-gel immobilization. The maximum reaction rate (rmax) was calculated to be 4.75 × 10−2 mol/(L g h).

Keywords
Mixed-gel immobilization; Transaminase; Bioconversion; κ-Carrageenan; l-Phenylalanine; Gelatin
First Page Preview
Bioconversion of phenylpyruvic acid to l-phenylalanine by mixed-gel immobilization of Escherichia coli EP8-10
Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 44, Issue 2, February 2009, Pages 142–145
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering