Abstract:

After treating with(NH4)2SO4 fractional precipitation and DEAESepharose anionexchange column, a thermoalkaliphilic catalase from Thermoascus aurantiacus was purifiedThe catalase identified by SDSPAGE was composed of two identical subunits and had a molecular weight of 1.9×105The catalase was highly active over a temperature range from 25℃ to 75℃ and a pH range from 7 to 13, having the optimum activity at 75℃ and pH 12These results demonstrated that the catalase was thermoalkaliphilicThe K m value for the purified catalase was 4074 mmol·L -1 and the k 2 value was 1.59× 10 4 μmol·(min·mg protein) -1.The catalase was immobilized onto chitosan beads by covalent bindingThe immobilized catalase showed higher pH stability and thermostability than the free catalaseIt retained about 55% of its initial activity after 13 repeated cycles during the total 130 min reaction timeThe properties mentioned above showed that this catalase had a potential application in removing residual hydrogen peroxide from bleaching streams in industrial bleaching processes.〖