The Backdrop Of Genetically-Engineered Proteolytic Bacteria For Functional Foods

Proteases are important for living organisms and they can be found everywhere. Proteases are the key enzymes in industrial applications. Microbial protease plays an important role in the biotechnological process. Proteases constitute one of the most important groups of enzymes both industrially and academically.

Proteases are the enzymes that hydrolyze proteins by the addition of water across peptide bonds and catalyze peptide synthesis in organic solvents with low water content [Sookkheo et al., 2000; Ishtiaq ahmed et al., 2010]. Proteases are essential constituents of all forms of life on earth, including bacteria, fungi, actinomycetes, plants and animals.

Proteases are classified according to their structure or the properties of the active site. There are several kinds of proteases such as serine, metallo, carboxyl, acidic, neutral, and alkaline [Nihan Sevinc and Elif Demirkan, 2011].

Proteases are the most important industrial enzymes of interest accounting for about 60% of the total enzyme market in the world and account for approximately 40% of the total worldwide enzyme sale [Godfrey And West, 1996; Chouyyok et al.

, 2005; Kuberan et al.2010]. They are generally used in detergents [Barindra et al., 2006], food industries [Mala et al., 1998; George et al., 1995, Hamid mukhtar and Ikram-ul-haq, 2008], meat processing, cheese making, silver recovery from photographic film, production of digestive and certain medical treatments of inflammation and virulent wounds [Rao et al., 1998; Paranthaman et al., 2009]. They also have medical pharmaceutical applications [Beg et al., 2003].

A wide range of microorganisms such as bacteria, fungi, actinomycetes and yeasts are known to date to produce proteases, a large potential of commercially available alkaline protease are derived from gram positive bacillus strains because of their ability to secret large amounts of alkaline protease having significant proteolytic activity and stability at considerable high pH and temperatures [Yang et al.

, 2000; Kumar, 2002]. Bacillus is highly favorable bacterium for protease production because it is non-pathogenic and well explored for producing various types of proteases.

Among Bacillus strains, B licheniformis, B subtilis, Bacidophilous and B lentus were important strains exploited industrially so far for protease production [Bhunia et al., 2010]. Bacillus species produce two types of proteases, alkaline and neutral. Bacterial neutral proteases are active in narrow pH range (pH 5 to 8) and have relatively low thermotolerance. This property is advantageous for controlling their activity during the production of food hydrolysis [Siddalingeshwara et al., 2010]. Normally, proteases are classified into three groups, i.e. acid, neutral and alkaline proteases, based on their acid-base behavior. Acid proteases are best performed at 2.0-5.0 pH and are mainly produced by fungi. Proteases with or around pH optima are called neutral proteases. Neutral proteases are primarily of plant origin, while proteases with optimal activity at pH range 8 and above are classified as alkaline proteases (H.S.Alnahdi.2012). The first enzyme produced in bulk is alkaline protease (M.Kalpana Devi et al 2008).

Proteases such as proteinases, peptidases or proteolytic enzymes break peptide bonds between protein amino acids. For this, they use a water molecule and are therefore classified as hydrolases. Proteases are two types of exopeptidases and end peptidases (Grewal S et al 2010).

Free proteases are mainly used in dry cleaning, detergents, meat processing, cheese production, silver recovery from photographic film, digestive treatment and certain medical treatments for inflammation and virulent wounds (Fekadu Alemu, 2015). Bacterial proteases are preferred for rapidly growing, needless space, easily maintained and accessible for genetic manipulation (Odu. N.N et al. 2012).