Lipases from Candida antarctica: Unique Biocatalysts from a Unique Origin

Thermostable alkaline protease from bacillus brevis and its characterization as a laundry detergent additive

A genomic DNA segment encoding an extracellular laccase was isolated from the thermophilic fungus Myceliophthora thermophila, and the nucleotide sequence of this gene was determined. The deduced amino acid sequence of M. thermophila laccase (MtL) shows homology to laccases from diverse fungal genera. A vector containing the M. thermophila laccase coding region, under transcriptional control of an Aspergillus oryzae alpha-amylase gene promoter and terminator, was constructed for heterologous expression in A. oryzae. The recombinant laccase expressed in A. oryzae was purified to electrophoretic homogeneity by anion-exchange chromatography. Amino-terminal sequence data suggests that MtL is synthesized as a preproenzyme. The molecular mass was estimated to be approximately 100 to 140 kDa by gel filtration on Sephacryl S-300 and to be 85 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Carbohydrate analysis revealed that MtL contains 40 to 60% glycosylation. The laccase shows an absorbance spectrum that is typical of blue copper oxidases, with maxima at 276 and 589 nm, and contains 3.9 copper atoms per subunit. With syringaldazine as a substrate, MtL has optimal activity at pH 6.5 and retains nearly 100% of its activity when incubated at 60 degrees C for 20 min. This is the first report of the cloning and heterologous expression of a thermostable laccase.

Characterization of the gene encoding an extracellular laccase of Myceliophthora thermophila and analysis of the recombinant enzyme expressed in Aspergillus oryzae.

Trichoderma spp. are known to produce enzymes with high xylanolytic activity. Different xylanases and various components of their xylanolytic system have been identified and purified. Some of the xylanases have been characterized extensively with respect to their physicochemical, hydrolytic, and molecular properties. Cellulase-free xylanase preparations have been tested successfully in industrial applications such as the prebleaching of kraft pulps in the pulp and paper industry. Future work on understanding the functional significance of xylanase multiplicity, the mechanisms of xylanase prebleaching, and the structural conformation of xylanases could lead to improved or alternative applications of Trichoderma xylanases.

Trichoderma Xylanases, Their Properties and Application

This review provides current information on starch and its molecular composition, common and potential sources, and manufacturing processes. It also deals with the five groups of enzymes involved in the hydrolysis of starch: the endo‐ and exoamylases, which act primarily on the α‐1,4 linkages; the debranching enzymes, which act on the α‐1,6 linkages; the isomerases, which convert glucose to fructose; and the cyclodextrin glycosyltransferases, which degrade starch by catalyzing cyclization and disproportionation reactions. This work mainly discusses the enzymatic processes for the manufacture of maltodextrins and corn syrup solids, including the production, both batch and continuous, of glucose syrup, and the processes to obtain sweeteners, such as maltose and 42, 55, and 90% high‐fructose corn syrups. It highlights the novel production of Schardinger's dextrins: the α‐, β‐, and γ‐cyclodextrins, consisting of six, seven, and eight glucose monomers, respectively. New products are emerging on the ma...

Amylolytic enzymes and products derived from starch: A review

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 fromBacillus licheniformis andBacillus stearothermophilus have replaced TL amylases fromBacillus subtilis. TS enzymes also have advantages in new areas such as cyclodextrin production. The TS cyclodextrin glycosyl transferase (CGTase) fromThermoanaerobacter sp. (95°C optimum) gives a higher productivity than the CGTase fromBacillus macerans (55°C optimum). In the area of enzymatic bleach boosting of wood pulps, a TS xylanase (Myceliophera 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 mesophileCandida antarctica produces a TS lipase which has a temperature optimum of 90°C when immobilized. The characterization of these enzymes will be described along with comparisons to some newly described TS enzymes.

Thermostable enzymes for industrial applications

A sulfhydryl oxidase from Aspergillus sojae, having a unit activity of about 2000 units per gm of protein enzyme preparation and essentially free from interfering activities.

Microbial sulfhydryl oxidase

Novel cyclodextrin glycosyl transferases (CGTase) can be produced by anaerobic cultivation of strains of Thermoanaerobacter or Thermoanaerobium. They are more thermostable than known CGTases and have temperature optimum about 95°C. The novel CGTases can be used for starch liquefaction at pH 4.5 and temperature exceeding 100°C in the production of dextrose or ethanol. They can also be used for conversion of liquefied starch to cyclodextrin at a temperature of 80-90°C.

Thermostable cyclodextrin glycosyl transferase, its production and use

Novel cyclodextrin glycosyl transferases (CGTase) can be produced by anaerobic cultivation of strains of Thermoanaerobacter or Thermoanaerobium. They are more thermostable than known CGTases and have temperature optimum about 95° C. The novel CGTases can be used for starch liquefaction at pH 4.5 and temperature exceeding 100° C. in the production of dextrose or ethanol. They can also be used for conversion of liquefied starch to cyclodextrin at a temperature of 80°-90° C. A method for enzymatically converting solid and liquefied starch into cyclodextrin using cyclodextrin glycosyl transferases (CGTase) elaborated by thermophilic obligate anaerobic strains belonging to the genus Clostridium. These CGTases are characterized by thermostability and a capability to liquefy starch and/or to convert liquefied starch to cyclodextrin at pH 5.0-5.5 and 60°-90° C.

Thermostable cyclodextrin glycosyl transferase and processes using it

This invention is in the field of glucose isomerization enzymes. More specifically, the invention is directed to a novel xylose isomerase, a process for the preparation of this enzyme, the use of this enzyme in glucose isomerization processes, and glucose isomerization processes. The enzyme is preferably derived from Thermotoga maritima or Thermotoga neapolitana. The enzyme has a temperature optimum above 90° C., pH optimum in the range of from 6 to 7 and a residual activity at 90° C. of more than 40% after 30 minutes and/or residual activity at 98° C. of more than 20% after 30 minutes. The enzyme can also be in immobilized form.

Robert L. Starnes

Papers

Thermostable enzymes for industrial applications

Microbial sulfhydryl oxidase

Thermostable cyclodextrin glycosyl transferase, its production and use

Thermostable cyclodextrin glycosyl transferase and processes using it

Xylase isomerase purified from thermotoga maritima and thermotoga neapolitana