Hemicellulase activity of antarctic microfungi

The mannanase (endo-beta-1,4-mannanase; E.C. 3.2.1.78) and xylanase (endo-beta-1,4-xylanase; E.C. 3.2.1.8) activity of five microfungal isolates from Antarctica were characterized at different temperatures and pH. In general, the hemicellulase activity of the antarctic strains occurred at least 10 degrees C and as much as 30 degrees C lower than that of a mesophilic reference strain. At 0 degrees C, two strains, a Phoma and a Penicillium, produced in excess of 40% of their measured maximum activity of mannanase. All strains had maximum hemicellulase activity in the range pH 4-5, with Penicillium, Phoma and Alternaria strains exhibiting high (in excess of 80% of maximum) mannanase activity at pH 10. Three of the antarctic isolates exhibited high levels of xylanase activity over a pH range of 3-11.