Nowadays, due to high levels of contamination present, the use of biodegradable natural materials and low environmental impact is increasingly necessary, both associated with compositions fertilizer as prepared protectors of seeds and plants, in order to achieve increase crop yields. Chitosan is a linear polysaccharide that is composed of two types of structural units randomly distributed (distribution Bernouliana) along the chain, the N-acetyl-D-glucosamine and D-glucosamine, which are joined together by glycosidic bonds of type β (1 → 4). Its properties envision greater economic effectiveness and practical than traditional agents, due to their excellent film forming along, which produces no pollutants, is biocompatible, no toxic, abundant in nature and renewable. There are many applications of this polymer in various fields, such as decontamination of industrial wastewater; as flocculant, biotechnology and food industry, in the biomedical and pharmaceutical industries.
Because of its ability to promote plant growth, inhibit microbial development and induce resistance to pathogens has important applications in agriculture. Chitosan oligosaccharides may be obtained mainly by two methods: chemical and enzymatic. However, the enzymatic degradation of chitosan polymers has higher effectiveness, because of the course of the hydrolysis reaction and distribution of products from it, are subject to a better control, in addition to promoting this method higher performance of the hydrolysis products. The chemical process can be carried out in two ways, homogeneous and heterogeneous. The homogeneous deacetylation pretreatment begins with swelling and eventual complete dissolution of chitin in cold (0° C) by using a ratio of chitin / NaOH 1:10 (w / v). Then subjected to deacetylation at temperatures close to the ambient temperature for long periods of time. The heterogeneous deacetylation, in some cases, is carried out in concentrated aqueous solutions of bases such as sodium hydroxide or potassium, under severe conditions (100-160 ° C).
CHITOSAN is used for seed coating, for preservation during storage and in releasing fertilizer systems.