PRELIMINARY PURIFICATION AND SOME PHYSICOCHEMICAL PROPERTIES OF A CELLULASE FROM PENICILLIUM SP. DTQ-HKl

Abstract

Penicillium sp. DTQ-HKI produced two extracellular cellulases with molecular masses of 58 and 36 kDa. Precipitated by 95% ethanol or acetone, 52 - 69% cellulases were yielded, and only one cellulase with the size of 58 kDa was obtained and designated as cellulase HKI. The enzyme had a temperature optimum at 60°C and pH optimum at 4.5, temperature stability in a range of 30 - 40°C and pH stability in a range of 4.5 - 6.0. Organic solvents (methanol, ethanol, isopropanol, n-butanol, and acetone) at concentration of 10 - 30% reduced I I - 67% of cellulase activity. Detergents as Tween 20, Tween 80, and Triton X-IOO at concentration of 0.5 - 2% reduced 3 - 53% of cellulase activity. SDS reduced 66 - 72% of cellulase activitr.' Metal ions Co2 +, K\ Ni2 +, Mg2+ at concentration ofS· 15 mM reduced 7 - 47% of cellulase activity. Zn +, Ca2 +, Cu2+, Fe3 + caused loss of2? -79% of cellulase activity. Ag+ ion inhibited cellulase strongly at low concentration of 5 mM, and decreased the cellulase activity by 8%, and completely inhibited the cellulase at higher concentration of 10 - 15 mM. In contrast, EDT A increased the residual activity from 19% at concentration of 5 mM to 45% at concentration of 10 mM and 59% at concentration of 15 mM. This cellulase might be an applicable enzyme for feed additives and cellulose degradation.