Highly Enantioselective Hydrolysis of Racemic Isopropyl Tert-Leucinate by Newly Discovered Baclicus Lincheniformis Jx010 for Synthesis of L-Tert-Butyl Leucine

Abstract:

Newly discovered strain Baclicus lincheniformis JX010 was identified to enantioselective hydrolysis of racemic ethyl tert-leucinate for the synthesis of chiral L-tert-butyl leucine. In the hydrolysis of isopropyl tert-butyl leucinate, the L-tert-butyl leucine was synthesized in 99% ee and 48% conversion. The cells was immobilized on synthetic resin 0501 without pretreatment to increase the enzyme stability. A series of organic cosolvents were investigated the hydrolysis rate and 2% glycerol was considered as the optimized cosolvent. In the hydrolysis of 50 mM isopropyl tert-butyl leucinate, the immobilized cells remained 85%activity with L-tert-butyl leucine in 99% ee after 8 reaction cycles.

• Periodical: Advanced Materials Research (Volumes 343-344)
• Pages: 453-456
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.343-344.453
• Online since: September 2011
• Authors: Jian Zhong Jin, Jie Zhang
• Keywords: Baclicus Lincheniformis Jx010, Hydrolysis, Immobilized Cell, Isopropyl Tert-Leucinate, L-Tert-Butyl Leucine

References

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[12] H. G. Schlege. Allgemeine Mikrobiologie, 1985, p.174. Table1 Tert-leucinate esters were catalyzed by the immobilized baclicus lincheniformis jx010 a Entry Substrate Conversion and ee (%)(5hr) Conversion and ee (%)(10hr).

[1] Methyl tert-leucinate.

[50] (85).

[50] (85).

[2] Ethyl tert-leucinate.

[50] (92).

[50] (92).

[3] Isopropyl tert-leucinate.

[48] (99).

[49] (99).

[4] Tert-butyl tert-leucinate.

[16] (99) 25(99) a The reaction was carried out in 20 ml 0. 2 M Tris-HCl buffer (pH 7. 0) with addition of 5 mM tert-leucinate ester containing 2g immobilized cells shaken at 30 oC and 200 rpm in 100-ml flasks. Table2 Influence of organic cosolvents on the hydrolysis of isopropyl tert-leucinate b organic cosolvents Log P relative rate Conversion and ee (%) (5hr) Methanol -0. 7 110.

[50] (95) Ethanol -0. 2.

[95] [50] (94) Propanol 0. 3.

[82] [41] (97) isopropanol 0. 3.

[72] [36] (98) Butanol 0. 3.

[65] [31] (94) THF 0. 5.

[56] [28] (95) DMSO -1. 3 141.

[50] (99) DMF -1. 0 165.

[50] (99) Glycerol -3. 0 195.

[50] (99) Tris-HCl buffer.

100.

[48] (99) b The reaction was performed in 20 ml 0. 2 M Tris-HCl buffer (pH 7. 0) with 5 mM isopropyl tert-leucinate by 2g immobilized cells shaken at 30 oC and 200 rpm in 100-ml flasks. 0. 2 ml (2%) organic cosolvents were added. The relative rate in the tris-HCl buffer was taken as 100 as the blank control. Figure1 Reuse of immobilized cells in the catalysis of 50 mM isopropyl L-tert-leucinate.

DOI: 10.7554/elife.04872.009