Industrial Perspectives: Bioactives and Enzymes
Among the many complex low-molecular secondary metabolites produced by Basidiomycetes are many of industrial interest, such as flavors, colorants or pharmaceuticals. The yield of these metabolites may be increased by the choice of growth substrate or by direct supplementation with metabolic precursors (biotransformation and bioconversion).
Compounds possessing anticancer, antibacterial, antiviral, antifungal, antidiabetic, anti-inflammatory, cardioprotective and other activities were reported. Low-molecular metabolites as well as some polycondensates were identified as responsible principles responsible. In various edible mushrooms inhibition of lipid oxidation and cyclooxygenase activity was mediated by linoleic acid, ergosterol, ergosterol peroxide and a glycosphingolipid. A polysaccharide, called Pleuran, possessing activity against Ehrlich ascites carcinoma and an esophageal cancer cell line was identified as a highly branched ß-D-glucan with 1-3 and 1-6 linkages in Pleurotus ostreatus. Schizophyllan, a homoglucan with a β-1,3-linked backbone and β-1,6-linked single glucose units, is produced by Schizophyllum commune and now explored as a yield enhancer in oil drilling.
In many cases, medicinal properties and chemical structures were difficult to correlate. Protection against breast cancer has been assigned to a reduced in situ production of estrogen through an unknown aromatase inhibitor. The pharmaceutical potential appears yet far from being fully explored.
The enzymes of white rot fungi possess or promise to receive industrial application in fields, such as of wood and textile processing and in converting renewable materials into fuels and fine chemicals. Fungal pre-treatment of wood chips, for example, is expected to be crucial in the utilization of agricultural wastes for the large-scale production of bioethanol. Because of their unique constellation of enzymes, basidiomycetes can degrade problematic dyes and environmental toxins. Therefore, these enzymes are suitable in environmental biotechnology for the de-colorization and decontamination of polluted water and other contaminated material.
With the advent of molecular biology, more and more species are also accessible by genetic engineering through DNA transformation techniques. Genetic engineering allows influencing production yields and will make possible in the future the production of better enzymes as well as of more and new metabolites.