Molecular and Biotechnological Aspects of Microbial Proteases

The review briefly elucidates the importance of proteases in living organisms and their wide range of potential applications in the vast areas of research and biotechnology. The important features of the proteases are also exploited in a number of ways and can be used to serve various applications in different industries. Apart from their natural potential of performing various important operations in living tissues, various microbial proteases have potential applications in a number of industries. In cellular environment, proteases are involved in the breakdown of the proteins' peptide bonds and transform them into smaller fragments of amino acids and peptides which are prerequisite for the differentiation and cellular growth. Proteases have also vast applications in a range of industrial procedures such as food, pharmaceutical, dairy and detergent. Microbial proteases have dominated roles in the industrial sectors. Microbial proteases are exploited for their characteristic feature of hydrolyzing the protein and the rest of the components of wheat and soy beans in the production of soy sauce. The production of proteases can be enhanced via substantiated fermentation methods. The variation in the composition of growth media such as changes in carbon and nitrogen ratio and some other features affecting microbial growth are significant in the evaluating the fermentation procedures. The production of microbial proteases is advantageous because they can be generated rapidly, their production is cost effective and the manipulation of microbial enzymes is quite easy. Proteolytic enzymes can be produced by either submerged fermentation (SmF) or solid state fermentation (SSF). But the latter is far more advantageous because it direct towards many potential benefits for the protease production. The review mainly focuses on the microbial protease production, their functional and structural aspects and the application of these proteolytic enzymes in different industries.

The focus of the present review is to provide an updated overview on the major sources and important applications of the microbial Proteases produced by a wide range of microorganisms that could resist extreme environments. In recent years there has been a phenomenal increase in the use of microbial proteases as industrial catalysts. These enzymes offer advantages over the use of conventional chemical catalysts for exhibiting high catalytic activity , high degree of substrate specificity, economically viable and can be produced in huge amounts etc. The selection of this topic is mainly based on the different characteristics of proteases to address wide application in various industrial sectors. Protease enzymes constitute one of the most important groups of industrial enzymes being extensively used in the food, pharmaceutical, protein hydrolysis, detergent, cheese-making, brewing, photographic, baking, meat, leather industries , inclusions in animal and human food as digestive aids etc. It can be obtained commercially from plants, animals and microbial sources.

Proteases are enzymes with highly specialized proteolytic functions. They are ubiquitous in occurrence, being found in all living organisms, and are essential for cell growth and differentiation. They not only have several physiological functions and roles in the living beings but are also of great importance in various industries as well thus providing a lot of economic benefits.

Proteases are a broad family of hydrolytic enzymes with various applications in chemical, cosmetics, and pharmaceutical industries. Owing to their physiological necessity, proteases are found in diverse sources including microorganisms. Our objective study was to search for a high quality and inexpensive source for the production of microbial proteases under different culture and growth conditions. Also, we aimed to characterize microbial proteases. Proteases-producing bacteria were isolated from soil samples collected from a poultry waste site. Soil samples were inoculated in skimmed agar media and 48 h later, colonies producing clear zones were selected as the source of microorganisms producing enzyme. The isolates were used to inoculate liquid media and the clear supernatant was taken as a crude for enzyme preparation. The enzyme was isolated and purified with ammonium sulfate at 60-80% saturation followed by dialysis. Subsequently, characterization of the enzyme fraction with the highest activity was carried out. The results indicated that the isolated enzyme with (60-80%) fractionation of ammonium sulfate exhibited the highest specific activity. In addition, the optimal temperature for enzyme activity was determined at 70ºC at pH values of 0.05M of acetate buffer 3.6 and 0.05M of glycine-NaOH buffer 10.0. Finally, the kinetic parameters (Michaelis–Menten constant, Km and maximal reaction velocity, Vmax) were calculated as 0.11 µmole/ml and 0.5x104 nmole of tyrosine/ml/hour, respectively. In conclusion, our findings provide evidence that the isolated bacteria represent a rich source of thermostable proteases. Indeed, more studies are still required to obtain such proteases in a purified form suitable for studying their applications.

Enzymes have greatly contributed to environmentally adapted clean and green technology due to their biodegradable nature and therefore have replaced harsh chemicals to a great extent. Proteases are a unique class of enzymes as they possess both degradative and synthetic properties. Their applications in industry and therapeutics have grown rapidly in the last two decades. Proteases comprise a vast group of enzymes with applications in various industries viz; pulp and paper, textiles, detergent, leathering, baking and bioremediation processes. In the present review, classification, major sources and physiological properties of proteases have been discussed. In addition to this, an overview on the applications of proteases in agriculture, tannery, food processing, silver recovery and pharmaceutical industry is also addressed briefly. This review mainly focuses on the challenges and the future scope of protease enzymes.

3 Biotech

Proteases are ubiquitous enzymes, having significant physiological roles in both synthesis and degradation. The use of microbial proteases in food fermentation is an age-old process, which is today being successfully employed in other industries with the advent of 'omics' era and innovations in genetic and protein engineering approaches. Proteases have found application in industries besides food, like leather, textiles, detergent, waste management, agriculture, animal husbandry, cosmetics, and pharmaceutics. With the rising demands and applications, researchers are exploring various approaches to discover, redesign, or artificially synthesize enzymes with better applicability in the industrial processes. These enzymes offer a sustainable and environmentally safer option, besides possessing economic and commercial value. Various bacterial and fungal proteases are already holding a commercially pivotal role in the industry. The current review summarizes the characteristics and types of proteases, microbial source, their current and prospective applications in various industries, and future challenges. Promoting these biocatalysts will prove significant in betterment of the modern world.

2016

Proteases catalyze hydrolysis of peptide bonds in proteins and are one of the most widely used industrial enzymes. Though they are ubiquitously found in a wide diversity of sources such as plants, animals, and microorganisms but microbial sources are preferred for the production of proteases due to technical and economic advantages. Microbial proteases have potential for application in different industries including detergent, leather, silver recovery, dairy, baking, beverages and pharmaceutical industries. These hydrolytic enzymes are efficiently involved in food industry for enhancing nutritional value, digestibility, palatability, flavour and reducing allergenic compounds as well as in management of domestic and industrial wastes. Furthermore, they are also involved in synthesis and structural elucidation of proteins. The present communication is an overview of the proteases produced from bacterial and fungal sources and their role in various industrial applications. Keyword: Pro...

Frontiers in Bioengineering and Biotechnology, 2019

The use of chemicals around the globe in different industries has increased tremendously, affecting the health of people. The modern world intends to replace these noxious chemicals with environmental friendly products for the betterment of life on the planet. Establishing enzymatic processes in spite of chemical processes has been a prime objective of scientists. Various enzymes, specifically microbial proteases, are the most essentially used in different corporate sectors, such as textile, detergent, leather, feed, waste, and others. Proteases with respect to physiological and commercial roles hold a pivotal position. As they are performing synthetic and degradative functions, proteases are found ubiquitously, such as in plants, animals, and microbes. Among different producers of proteases, Bacillus sp. are mostly commercially exploited microbes for proteases. Proteases are successfully considered as an alternative to chemicals and an eco-friendly indicator for nature or the surroundings. The evolutionary relationship among acidic, neutral, and alkaline proteases has been analyzed based on their protein sequences, but there remains a lack of information that regulates the diversity in their specificity. Researchers are looking for microbial proteases as they can tolerate harsh conditions, ways to prevent autoproteolytic activity, stability in optimum pH, and substrate specificity. The current review focuses on the comparison among different proteases and the current problems faced during production and application at the industrial level. Deciphering these issues would enable us to promote microbial proteases economically and commercially around the world.

Research Journal of Biotechnology

The use of enzymes in applied biotechnology has progressively increased in both industrial processes, products and in medical field. Proteolytic enzymes play an important regulatory role in many physiological processes and also represent a therapeutic target for several diseases including cancer, hypertension, blood clotting disorders, respiratory and viral infection. Proteases, a largest and ubiquitous class of enzymes, have a divergent role in biomedical field. The current review includes the basic information about the protease classification and optimized growth parameters to maximize the production of alkaline proteases and applications of proteases in a wide variety of industries including leather, textile, food manufacturing, pharmaceutical, detergent and waste management. The review also implicates the importance of genetic tools to obtain the novel engineered protease with improved catalytic performance and stability, pH and thermal tolerance.