Aproveitamento biotecnológico de resíduos agroindustriais na produção de glucoamilase

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The Alto Vale do Itajaí region is a big producer of cassava flour for starch. The processing of the cassava flour generates residues which are usually disposed in the environment in an inadequate way, leading to an environmental impact. This way, the biotechnology proves itself to be an interesting alternative in transforming these residues, which still contain considerable nutrients, into other products. Thus, this present work has had, as a goal, to utilize one of the residues of the starch factories, the cassava bagasse added to the wheat bran, for the production of the glucoamylase enzyme, used in the pharmaceutical and food industry. The experiments were conducted on reactors of fixed bed trough the technique of fermentation in solid condition by Rhizopous oryzae ATCC 34612. The development of the work happened in three distinct and subsequent stages, and the first experimental stage had the objective of finding the best combination of the mentioned residues. It studied the proportions of 9:1, 8:2 and 7:3 of cassava bagasse and wheat bran, respectively. The best composition obtained for the production of the glucoamylase was the composition 8 parts of cassava bagasse to two parts of wheat bran, obtaining the activity of 66 U/gms and productivity of 5,5 U/gms.h. At the moment of maximum enzymatic production the reduction of pH of the means in all cultivations was observed. During the course of the cultivations, the level of humidity in solid state remained stable and the small variations of this parameter did not interfere in the production of the glucoamylase. At the second experimental stage, taking as a reference the 8:2 cultivation, the parameters studied in the variations of operational conditions were aeration outflow, inoculum concentration and humidity of the solid state. From the pattern of 1,0L/min air outflow, 104 spores by gram of solid state, inoculum concentration and humidity of the solid state of 70%, the variations 0,5 and 2,0L/min of air, 102 and 106 spores/grams and humidity of the solid state of 60% and 80% were realized. The results revealed that the parameters used in the first experimental stage were the ideal ones for the production of glucoamylase. In the ambit of energy economy the results revealed that it is possible to conduct the cultivations with 60% of humidity of the solid state, aeration outflow of 0,5L/min without interfering in the activity and productivity of the glucoamylase, whereas the reduction in the volume of the spores did not show viability of application, considering that there was decreasing in the enzymatic production. The same way, the elevation of the volume of inoculum, which is twice as big as the standard, is not favorable in the conduction of the cultivations, considering that there was a little elevation in the activity of glucoamylase, passing from 66U/gms to 71 U/gms. At the third experimental stage, which intended to vary the parameters in the process of the extraction of enzyme in the solid state, was observed that the imposed variations can being utilized because they are viable under the point of view of energy economy and the utilization of materials. The possibility of replacing the acetate cap by sterile distilled water, without the need of orbital stirring or the control of temperature previously fixed on 30 C, suggests an innovation in the methodology of the extraction of enzymes from the solid state

ASSUNTO(S)

glucoamylase resíduos agroindustriais engenharias solid state fermentation agronomical industry residues glucoamilse fermentação em estado sólido biotecnologia agrícola; biotecnologia - aspectos ambientais; resíduos agrícolas - reaproveitamento

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