Estudo da otimização da produção de inulinase por Kluyveromyces marxianus NRRL Y-7571 em meios industriais pre-tratados. / Studies of the otimização of the production of inulinase for Kluyveromyces marxianus NRRL Y-7571 in half daily pay-treat industrials.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

Inulinase is an enzyme relevant to fructose production by enzymatic hydrolysis of inulin. This enzyme is also used in the production of fructooligosaccharides that may be used as a new food functional ingredient. Commercial inulinase is currently obtained using inulin as substrate, which is a relatively expensive raw material. In Brazil, the production of this enzyme using residues of sugarcane and corn industry (molasses and corn steep liquor) is economically attractive, due to the high amount and low cost of such wastes. The reduction of process costs has already been verified at the Laboratory of Bioprocess Engineering ? UNICAMP, where it was shown that higher enzymatic activities may be obtained with industrial rather than the synthetic medium. However, industrial media usually contain inhibitory compounds and suspended matter, thus demanding a pretreatment to clarify and remove the undesirable compounds. The pretreatment of fermentation media could also help the downstream processing for enzyme recovery and purification, though care should be taken on the choice of pretreatment process to avoid loss of fermentation yield. In this context, the aim of this work was the assessment of inulinase production using pretreated industrial media by .OX HURP HV_ PDU[LDQXV_ NRRL Y-7571. Firstly, different pretreatments of the fermentation medium were investigated. Adsorption by activated coal was found to be the most appropriate process to pretreat the industrial medium. Enzyme production in shaken flasks was optimized after determining the best pretreatment process. In this study three complete factorial designs were performed, yielding enzymatic activities as high as 1,300 U.mL-1 in 72 h of fermentation, obtained by fermentation of a medium containing 150 g.L-1 of molasses, 50 g.L-1 of corn steep liquor and 6 g.L-1 of yeast extract. Preliminary experiments were carried out to investigate the possibility of enzyme purification in an expanded bed Streamline DEAE resine. The production of the enzyme was scaled up in a bench bioreactor by two experimental designs. A screening design (Plakett-Burman) was used to assess the significant factors that influence the process. A second order complete experimental design was then performed to optimize inulinase production in the bioreactor. The optimized medium contained 250 g.L-1 of molasses, 80g.L-1 of corn steep liquor and 6 g.L-1 of yeast extract and enzymatic activities 1,300 U.mL-1 of inulinase in a bioreactor operating at a stirring and aeration rate of 300 rpm and 1.5 L of air. (L of medium)-1.min-1, respectively .

ASSUNTO(S)

inulinase experimental planning inulinase pay-treatment kluyveromyces marxianus pre-tratamento kluyveromyces marxianus planejamento experimental

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