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Structure-Guided Modification of Rhizomucor miehei Lipase for Production of Structured Lipids.

Authors :
Zhang, Jun-Hui
Jiang, Yu-Yan
Lin, Ying
Sun, Yu-Fei
Zheng, Sui-Ping
Han, Shuang-Yan
Source :
PLoS ONE; Jul2013, Vol. 8 Issue 7, p1-9, 9p
Publication Year :
2013

Abstract

To improve the performance of yeast surface-displayed Rhizomucor miehei lipase (RML) in the production of human milk fat substitute (HMFS), we mutated amino acids in the lipase substrate-binding pocket based on protein hydrophobicity, to improve esterification activity. Five mutants: Asn87Ile, Asn87Ile/Asp91Val, His108Leu/Lys109Ile, Asp256Ile/His257Leu, and His108Leu/Lys109Ile/Asp256Ile/His257Leu were obtained and their hydrolytic and esterification activities were assayed. Using Discovery Studio 3.1 to build models and calculate the binding energy between lipase and substrates, compared to wild-type, the mutant Asp256Ile/His257Leu was found to have significantly lower energy when oleic acid (3.97 KJ/mol decrease) and tripalmitin (7.55 KJ/mol decrease) were substrates. This result was in accordance with the esterification activity of Asp256Ile/His257Leu (2.37-fold of wild-type). The four mutants were also evaluated for the production of HMFS in organic solvent and in a solvent-free system. Asp256Ile/His257Leu had an oleic acid incorporation of 28.27% for catalyzing tripalmitin and oleic acid, and 53.18% for the reaction of palm oil with oleic acid. The efficiency of Asp256Ile/His257Leu was 1.82-fold and 1.65-fold that of the wild-type enzyme for the two reactions. The oleic acid incorporation of Asp256Ile/His257Leu was similar to commercial Lipozyme RM IM for palm oil acidolysis with oleic acid. Yeast surface-displayed RML mutant Asp256Ile/His257Leu is a potential, economically feasible catalyst for the production of structured lipids. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
19326203
Volume :
8
Issue :
7
Database :
Complementary Index
Journal :
PLoS ONE
Publication Type :
Academic Journal
Accession number :
89626992
Full Text :
https://doi.org/10.1371/journal.pone.0067892