Production of protease by aspergillus flavus in solid state fermentation

Thesis Overview

<p> </p><p><strong>1.0 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;</strong><strong>INTRODUCTION</strong></p><p><strong>1.1 &nbsp; &nbsp; Background of the study</strong></p><p>Protease constitutes a large and complex group of enzymes that plays an &nbsp;important nutritional and &nbsp;regulatory &nbsp;role in nature. Proteases are (physiologically) necessary for &nbsp;living organisms; they are ubiquitous and found in a wide diversity of sources. Protease is the most important industrial enzyme of interest accounting for about 60% of the total enzyme market in the world and account &nbsp;for approximately 40% of &nbsp;the total worldwide enzyme sale (Godfrey and West, 1996; Chouyyok <em>et al.</em>, 2005). They are generally used in detergents (Barindra <em>et al.</em>, 2006), food industries, leather, meat processing, cheese making, silver recovery from photographic film, production of digestive and certain medical treatments of inflammation and virulent wounds (Rao <em>et al.</em>, 1998; Paranthaman <em>et al.</em>, 2009). They also have medical and pharmaceutical applications.</p><p>Microbial &nbsp;proteases &nbsp;are &nbsp;degradative &nbsp;enzymes &nbsp;which catalyze the total hydrolysis of proteins (Raju <em>et al.</em>, 1994; Haq <em>et al.</em>, 2006). The molecular weight of proteases ranges from 18 – 90 kDa &nbsp;(Sidney and Lester, 1972). These enzymes are found in a wide diversity of sources such as plants, animals and microorganisms but they are mainly produced by bacteria and fungi. Microbial proteases are predominantly extracellular and can be secreted in the fermentation medium.</p><p>In the production of protease, it has been &nbsp;shown to be inducible and was affected by the nature of the substrate used in fermentation. Therefore, the choice of an appropriate inducing substrate is of great importance. Different carbon sources such as wheat bran, rice straw, rice bran, cotton &nbsp;and &nbsp;bagasse have been studied for the induction and biosynthesis of protease. However, wheat bran is a superior carbon source for the production of protease by <em>Aspergillus flavus</em>. So the further studies were carried out by using wheat bran as carbon source.</p><p>The use of agro-industrial residues as the basis for cultivation media is a matter of great &nbsp;interest, aiming to decrease the costs of enzyme production and meeting the increase &nbsp;in &nbsp;awareness &nbsp;on &nbsp;energy &nbsp;conservation &nbsp;and recycling (Singh <em>et al.</em>, 2009). &nbsp;Major &nbsp;impediments to the exploitation of commercial enzymes are their yield, stability, specificity and the cost of production. New enzymes for use in commercial applications with desirable biochemical and physiochemical characteristics and low production cost have been focus of much research (Kabli, 2007). Solid state fermentation (SSF) was chosen for the present research because it has been reported to be of more grated &nbsp;productivity than that of submerged fermentation (Ghildyal &nbsp;<em>et al.</em>, 1985; Hesseltine, 1972). Economically, SSF offers many advantages including superior volumetric productivity, use of simpler machinery, use of &nbsp;inexpensive &nbsp;substrates, simpler downstream &nbsp;processing, and lower energy requirements when compared with submerged fermentation (Paranthaman <em>et al.</em>, 2009).</p><p><strong>1.2 &nbsp; &nbsp; Aim of the study</strong></p><p>The aim of &nbsp;this &nbsp;study &nbsp;was &nbsp;to produce &nbsp;protease from <em>Aspergillus flavus </em>using wheat bran as a substrate under Solid State Fermentation.</p><p><strong>1.3 &nbsp; &nbsp; Objectives of the study</strong></p><p>The objectives of the study include:</p><ul><li>To isolate <em>Aspergillus &nbsp;flavus</em>&nbsp;from spoilt bread in Gwagwalada.</li><li>To determine the frequencies of occurrence of &nbsp;the isolated <em>Aspergillus flavus</em>&nbsp;from spoilt bread using simple percentages.</li><li>To determinethe proteolytic potential of the isolated fungi using basal medium.</li><li>To determine the quantity of the protease enzyme produced by the isolated fungi using spectrophotometer.</li></ul> <br><p></p>