Extremophilic Amylases: Microbial Production and Applications

Amylases are widely distributed and have various industrial applications. Microbes play a major role when bulk production of enzymes is desired. Enzymes which can work in harsh conditions like high or low pH, high salt concentration, and high or low temperature are of special interest. As starch solution has a lower pH, conversion of starch needs to be adjusted in terms of pH or require acid-stable amylases for working at lower pH. Thermophilic amylases are prerequisite for industrial processes like liquefaction followed by saccharification of starch at higher temperatures. Psychrophilic amylases are considered to reduce energy requirements when utilized in wastewater treatments during winters. Halophilic amylases may reduce contamination risk and can contribute to low-cost amylase production. Use of thermostable and acid-stable or -tolerant amylases can enhance conversion of starch into sugar by manyfold. Bacillus licheniformis is notable for thermophilic amylase while Alteromonas haloplanktis for psychrophilic amylase. Amylases are used in various industries like sugar, paper and pulp, textile, detergent, bread making, and brewing; biofuel production; and treatment of starch processing wastewater. In this chapter, we have discussed microbial sources for the production of distinct amylases working in extreme conditions.