Bacterial alkaline proteases: molecular approaches and industrial applications

Abstract

Proteolytic enzymes are ubiquitous in occurrence, being found in all living organisms, and are essential for cell growth and differentiation. The extracellular proteases are of commercial value and find multiple applications in various industrial sectors. Although there are many microbial sources available for producing proteases, only a few are recognized as commercial producers. A good number of bacterial alkaline proteases are commercially available, such as subtilisin Carlsberg, subtilisin BPN' and Savinase, with their major application as detergent enzymes. However, mutations have led to newer protease preparations with improved catalytic efficiency and better stability towards temperature, oxidizing agents and changing wash conditions. Many newer preparations, such as Durazym, Maxapem and Purafect, have been produced, using techniques of site-directed mutagenesis and/or random mutagenesis. Directed evolution has also paved the way to a great variety of subtilisin variants with better specificities and stability. Molecular imprinting through conditional lyophilization is coming up to match molecular approaches in protein engineering. There are many possibilities for modifying biocatalysts through molecular approaches. However, the search for microbial sources of novel alkaline proteases in natural diversity through the "metagenome" approach is targeting a hitherto undiscovered wealth of molecular diversity. This fascinating development will allow the biotechnological exploitation of uncultured microorganisms, which by far outnumber the species accessible by cultivation, regardless of the habitat. In this review, we discuss the types and sources of proteases, protease yield-improvement methods, the use of new methods for developing novel proteases and applications of alkaline proteases in industrial sectors, with an overview on the use of alkaline proteases in the detergent industry.

Optimization of Parameters that Affect the Activity of the Alkaline Protease from Halotolerant Bacterium, Bacillus acquimaris VITP4, by the Application of Response Surface Methodology and Evaluation of the Storage Stability of the Enzyme

“…It is desirous that the biocatalysts need to have adequate storage as well as operational process, operational stability, so that their applicability at a high temperature, extreme pH, compatibility with organic solvent, and detergent can find suitable application in therapeutics, diagnostics, peptide synthesis, detergent formulations (33,34). Crude preparations are generally more stable than the purified enzymes.…”

Novel Keratinolytic Activity of Cyberlindnera fabianii Nrc3 Aza as A Plant Growth Promoting Agent (PGPA)

“…Microbial keratinolytic enzymes have been described for various biotechnological applications in food, detergents, textiles, and leather industries, and yet the growing demand for these enzymes necessitates the screening for novel keratinolytic microorganisms with potential applications (Gupta et al, 2002). A total of 14 pure cultures were isolated and purified which obtained from different samples collected from Governorates of Egypt.…”

Improving production of extracellular proteases by random mutagenesis and biochemical characterization of a serine protease in Bacillus subtilis S1-4

“…Over the past several years, there has been an increase in the application of proteases in various industries, such as detergent additives, food and feed processing, pharmaceutical, and leather and silk processing (Gupta et al, 2002). Microorganisms are an important source of proteases due to their fast growth, simple fermentation conditions, special metabolic processes, and wide distribution.…”