Cloning,expression and characterization of the esterase Tm1350 from hyperthermophilic bacteria Thermotoga maritima

The esterase gene Tm1350 from Thermotoga maritima was amplified by PCR method and recombinant plasmid p ET15b- Tm1350 was constructed to express the enzyme in Escherichia coli BL21( DE3).Esterase activity was determined spectrophotometrically by the p- NPA method using p- nitrophenyl esters of various chain lengths as the substrates.The enzyme could hydrolyze the substrates of p NP- esters with acyl chains of different lengths and exhibited the highest activity for p NP- C5 among the substrates tested. Tm1350 displayed optimal activity at70℃ and 6.5.It maintained above 50% activity after 5h incubation at 90℃,which indicated that the enzyme showed strong thermal stability. The recombinant esterase Tm1350 was found to have strong resistances to metal ions,inhibitor,denaturant and organic solvents.