科研之友
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摘要
The production, purification, characterization and application of a novel cold active esterase by Pseudomonas sp. TB11 are described herein. A new finding regarding the production of extracellular esterase activity depending upon single cream as an inducer used for growth was investigated in this study. The crude esterase was subjected to a three-step enzyme purification, which resulted in a 15.21-fold purification and the specific activity of the final purified esterase increased to 1526.2 U/mg protein and purified EstTB11 had a molecular mass of 65 kDa. The N-terminal sequence of ten amino acids were: GVYDYKNLTT. Peptide mass finger printing revealed that some peptides showed homologues sequences (29%) to polyurethanase of Pseudomonas sp. FH4. Furthermore, the enzyme displayed the optimum pH of 8.5 and optimum temperature of 25 degrees C and significantly high stability at 15-35 degrees C for 72 h. The enzyme was incubated with different metal ions at concentrations of 5 and 10mM, the activity of esterase was increased in the presence of K+, Na+ and Mg2+ and decreased with Ca2+,Al3+, Mn2+, and Fe3+. Experiments indicated that EstTB11 could hydrolyze milk fat to produce short and medium-chain fatty acid and this result layed the foundation for the application in increased aroma of milk products.
