| Resumo: |
Currently, in the paper industry, it is generated a large amounts of industrial waste. Specifically in the bleaching stage, the waste produced contains a high amount of toxic substances such as chlorine and ozone, generating a considerable risk to the environment and to human and animal health, thus, the treatment before disposal is essential, but generates costs for this sector. The production of cellulase using this raw material aims to contribute to the reduction of costs for the industry and the production of products with quality, besides reducing the damages caused to the environment. Cellulases can be applied in various industrial sectors, replacing chemical catalysts, aiding in textile finishing processes, in the food industry and in animal nutrition. The objective of this study was to optimize the production of cellulase using two residues from the pulp bleaching process of a paper agroindustry and evaluate the action of enzymes in the hay. The residues were characterized physicochemically for determination of organic and inorganic constituents and pH. The production was done by submerged liquid fermentation using the Aspergillus niger microorganism, inoculated in culture medium described in the literature, plus the residues, separately. To obtain the optimum production conditions, some variables were altered as pH, temperature, residue concentration, agitation and production period. The enzyme was semi purified with ammonium sulfate. The results showed the potential contaminant both residues once the levels of chlorides, pH, iron and sodium was above recommendation by CONAMA. The fungus was able to produce the cellulase, using the residues as inductors fungus produced cellulose in presence of both residues, and the acid was the better inductor, under the following conditions: 50% acid residue: 7 days of production, pH 8.0, agitation at 100 rpm and at 45°C.The ability to favor digestibility in vitro tests, which simulated the bovine rumen. The results showed that there was an improvement in digestion, where enzyme by residue 2 was more efficient than enzyme by alkaline residue, such as in cellulose, at the time of 180 minutes. Comparing the pre and post-digestion analyzes, it was observed that there was partially significant digestion of the fibers analyzed, showing the capacity of the enzymes produced in hydrolyzing molecules of the cellulosic complex. |
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