Fungal Enzymes: Present Scenario and Future Perspectives
- Pp. 3-27 (25)J.L. Uma Maheswar Rao, G.D.Y. Boorgula and Ana Lúcia Leitão
As a conservative estimate, some 120,000 species of fungi have been isolated. Many of these have been screened for their ability to produce industrially sound products. Fungi have been important in both ancient and modern biotechnological processes. They are of excellent value in nutrition, processes and products that utilize fungi include production of sugars, antibiotics, enzymes, organic acids, baking, brewing, alcohols, and numerous pharmaceuticals. α-Amylases and glucoamylases are used in the conversion of starch into different sugar syrups. Industrial applications generally require amylases with a very specific hydrolysis profile. The commercially used fungal amylases have certain limitations such as moderate thermostability, acidic pH requirement, and slow catalytic activity that increase the process cost. The importance of retrogradation of starch fraction in bread staling has been emphasized. A loss of more than US$1 billion is incurred in USA alone every year due to the staling of bread in winters. There is a need for good additives and enzymes for preventing staling and to improve the texture and shelf life of baked products. Pectinases are one of the upcoming enzymes of fruit and textile industries. These enzymes are required for the break down of complex polysaccharides of plant tissues into simpler molecules like galacturonic acids. The role of acidic pectinases in bringing down the cloudiness and bitterness of fruit juices is well established. The production of pectinolytic enzymes has been widely explored in filamentous fungi. However, there are a very few reports on the production of pectinases by thermophilic moulds for food applications. About two thirds of the phosphorus in plant ingredients for pigs and poultry is in the form of salts of phytic acid (myoinositol hexakisphosphates, phytates), which are not very soluble and of very limited digestibility. This area of research has advanced to the extent that enzymes are commonly required in poultry diets to enhance the nutritive value of cereals. This review focuses attention on the present status of knowledge on the production, characterization, and potential applications of fungal biocatalysts (alpha amylases, glucoamylases, pectinases and phytases) in food industry.