THERMOSTABLE ENZYMES FOR INDUSTRIAL APPLICATIONS

The variety of thermostable (TS) enzymes has been steadily increasing for use in industrial applications, mainly as replacements for thermolabile (TL) enzymes. For example, TS amylases from Bacillus licheniformis and Bacillus stearothermophilus have replaced TL amylases from Bacillus subtilis. TS enzymes also have advantages in new areas such as cyclodextrin production. The TS cyclodextrin glycosyl transferase (CGTase) from Thermoanaerobacter sp. (95-degrees-C optimum) gives a higher productivity than the CGTase from Bacillus macerans (55-degrees-C optimum). In the area of enzymatic bleach boosting of wood pulps, a TS xylanase (Myceliopthera thermophila) would be advantageous over a TL xylanase (Trichoderma reesei), due to the high temperature of the incoming pulp. Not all TS enzymes are from thermophiles; the mesophile Candida antarctica produces a TS lipase which has a temperature optimum of 90-degrees-C when immobilized. The characterization of these enzymes will be described along with comparisons to some newly described TS enzymes.