Extreme Environments: Goldmine of Industrially Valuable Alkali-stable Proteases

Abstract

Since the advent and release of Bio 40 (the first detergent with bacterial alkaline protease) in 1959, exploration of the microbial alkaline proteases has been exploited beyond expectations. The inventory of microbial alkaline proteases is difficult to draft as it is increasing daily. Most of these proteases are the result of studies in which one or a few isolates were targeted for an alkali-stable enzyme. Although, the worldwide research on microbial alkaline proteases has been widely performed, we still need an improved enzyme capable of catalyzing reactions under extreme conditions (also called as extremozymes), e.g., high alkalinity and salinity, anhydrous environment, cold and hot environment, etc. As the search for extremozymes is in progress, it is imperative to explore the extreme environments to get some novel microbial strains (extremophiles) for alkali-stable proteases. This review article is an effort to compile the scattered information on some extremophiles and their alkali-stable proteases, which may have better specific industrial applications. It includes: (i) various extreme environments relevant to industrial biocatalysts, (ii) strategies of extremophilic microbes and enzymes which make them able to tolerate such conditions, and (iii) an overview of some important work done so far to explore industrially relevant extremophilic enzymes from extremophiles.