Chitinases Potential as Bio-Control

The richest second polysaccharide in nature later than cellulose is chitin. It is present in the exoskeleton of yeast, fungi, algae and insects. It is also present in the inner structure of different vertebrates. The degradation of chitin is done by chitinases enzymes. In the environment nitrogen and carbon are generated by the contribution of chitinases. In biotechnological applications chitinolytic enzymes and chitin have gaining their signifi -cance. In the field of agriculture for the control of pathogens particularly the chitinases demoralized. Some human diseases particularly such as asthma, chitinases have a broad use for human health care. For the preparation of pharmaceutically significant chito-oli gosaccharides and preparation of single cell protein, N-acetyl D glucosamine, separation of protoplast from yeast & fungi, for the handling of chitinous squander, to stop the pathogenic fungi and to stop the morphogenesis and mosquitoes etc chitinases has wider range applications. We are discussed a different type of chitinases and the chitinases present in a number of organisms for example plants, bacteria, mammals and fungi in this review.


Introduction
In the sixty's midst, of the emergent uprising, chemical pesticides consumption is considered while the best selection for pest's reserve. But continuously use of these pesticides brought a high quality of toxicity and had a negative effect on groundwater and soil throughout the world [1,2]. Persistent pesticides are those which strongly bind with soil particles and are immobile for a long period of time. To remove the chemical pesticides from soil and groundwater is very difficult. Due to continuous use, they decrease the crop yield, soil quality and hazardous effect on agriculture field [3,4]. Due to these harmful effects there is need to drive non-harmful alternatives. Biocontrol agents and enzymes are used for this purpose. Here we discuss chitinase enzyme which is used as a bio-pesticide [5]. Chitinase is an enzyme which belongs to hydrolytic enzymes which have the capacity to degrade the pathogens chitin e.g. insects and fungi and even the insect larvae [6]. The chitin is major cuticle component of membrane peritrophic which is the protective lining of the gut of many insects. The chitinase enzyme catalyzes this chitin into its monomers.
Many micro-organisms produce this enzyme in which fungi also include e.g. such as Metarhiziumanisopliae, bacteria name ly Bacillus pumilus, Serratia marcescens and Bacillus cereus, acti nomycetes such as Streptomyces spp. and yeasts such as Tilletiopsiswashingtonensiss and Tilletiopsisalbescens [7][8][9]. Microbes which produce chitinase enzyme used for the control of insect nuisance and efficiency of bio-control related whit production of chitinase. Polysaccharides happen in the numeral of crystalline form except α-chitin is recognized in the insect. Neighbor poly-Glc-NAc chains work anti-parallel together in this form. Chitin includes different types of chitin-binding lectins which interact with that protein [10][11][12]. The mainly second rich biopolymer on this planet is chitin which is β-1, 4-N-acetylglucosamine (GlcNAC), is a linear polymer. It is present on the outside of the skeleton of fungi, algae, insects, shrimps, yeasts, lobsters and crabs. Chitin is also present in the inner structure of other invertebrates [13,14]. The dry weight of chitin is approximately 20-58% and 75% is the overall shellfish (such as shrimp, krill, and crab) weight which is likely as waste.
Among a wide range of applications, the configuration of the extracellular chitinase is enhanced by the use of chitin [15,16].
The related materials of chitin have a wider use in the healing of wounds, delivery of drugs, treatment of wastewater and in di-etary fiber. It is a chief part to make pollution in coastal areas and is the inelastic polysaccharide, hard and white. Chitin is a beneficial chelating agent because it contains (6.89%) nitrogen which is a high percentage. Β-chitin and α-chitin are two allomorphic forms [17,18]. Polarities and packing of contiguous chains in the subsequent sheets are varying with these two forms of chitin. Chitinase degrades the chitin. Early cleavage of the polymer of chitin with the help of chitinases into oligosaccharides of chitin and additional cleavage to monosaccharides and N-acetylglucosamine by chit biases is a two-step process of chitin catabolism. 20kDa to 90kDa is approximately the size range of chitinases which are glycosyl hydrolases. These are present in broad varieties of organisms like yeasts, actinomycetes, bacteria, plants, arthropods, fungi and humans. Osteoarthritis treatment has been receiving particular concentration from N-acetylglucosamine (GlcNAc). The role in the bio-control of harmful insects and fungal phytopathogens chitinases has been getting better interest.
In the control of mosquito and defense system of plants beside chitin-containing pathogens chitinases play the significant role [19][20][21][22]. Human and animal diseases are caused by chitinases and chitin which are used by pathogens such as metazoan or protozoan. Exterior and interior (in host) environmental protection in pathogens is due to chitin coats. By the use of chitinase, they attack their host.
By the use of host chitin-containing structures, the infection is successfully transmitted from one invertebrate to another. Different bacterial species such as Escherichia, Streptomyces, Aeromonas, Alteromonas have the ability to produce chitinase [23,24]. The bacteria which are producing chitinase has been remote from shellfish squander, compost of park waste, soil, burning springs and gardens [25]. There are two main groups of chitinases: Exo-chitinases and endochitinase. The chitin is split randomly at internal sites by endochitinases. Therefore, they form the di-cetylchitobiose dimer and dissolvable lower molecular mass of GlcNAc multimers while chito-  Difference in molecular structure, catalytic mechanism and specificity of the substrate are shown by enzymes which are actually the chitinases diverse and huge group. It is beneficial to study the specificity of the substrate of chitinases, but it's not just revealed connection among physiological role and specificity of the substrate, it also allows ones to disgrace chitin into narrative foodstuffs which have industrialized application [5].
It is also known that all chitinase class can also exist in different specificity and reaction mechanism. In tobacco class 3 chitinase which consists of a large amount of lysozyme and also chitinase activity can also exist. In tobacco, class IV can also show the chitinase activity. In tobacco class iii and class, I can also use as an inverting mechanism which is used to the hydrolyzed beta-glycosidic linkage.
While the class III chitinase in tobacco has a retaining mechanism. Fn3 domains that a.re linked to the catalytic domain [8,9,31,32].

Insect Chitinases
The

Mammalian Chitinases
The chitinase of mammals is a group of 18 of glycosylhydrolases (GH18), which divides into proteins that are similar to chitinase with 0% activity of enzymes. Chitotriosidase was an earlier mammalian chitinase to be recognized. The terminal catalytic domain of GH18 family members has fractions of triose-phosphate isomerase fold, that will be characterized by the (β/α) 8 -barrel structure, and in this barrel, β4 strand contains conserved sequence motif. Glutamic acid is the basic portion that is giving a proton necessary for hydrolyzing the β (1-4) glycosidic bond present in chitin; this would be the re-arrangement of that compulsory glutamic acid to glutamine, leucine, and isoleucine that is responsible for the shortage of chitinolytic activity. Anyhow, the barrel will be neutral; it has now the ability of binding to chitin with huge affinity [3,4]. However, still, they need some chitinolytic enzymes.

Future Prospects
Researchers are trying to seek out new functions of chitinase enzymes. Chitinase will is also accustomed increase lifetime of food as the food preservative. As we'd realize the enzymes and its thera-