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URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11847
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Item Characterization of an exoinulinase produced by Aspergillus terreus CCT 4083 grown on sugar cane bagasse(Journal of Agricultural and Food Chemistry, 2010-02-07) Coitinho, Juliana B.; Guimarães, Valéria M.; Almeida, Maíra N. de; Falkoski, Daniel L.; Queiróz, José H. de; Rezende, Sebastião T. deExoinulinase (β- D -fructan fructohydrolase, EC 3.2.1.80) secreted by Aspergillus terreus CCT4083 was obtained using sugar cane bagasse, an agroindustrial residue, as a carbon source. It was further purified from the supernatant culture in a rapid procedure. The enzyme presented 57 kDa on SDS-PAGE and 56 kDa on gel filtration chromatography. Inulin was hydrolyzed by the purified enzyme, yielding D -fructose as the main product. This enzyme showed maximum activity at pH 4.0 and 60 °C and maintained more than 90 and 75% of its original activity at 40 and 50 °C, respectively, after 3.5 h of preincubation. The K M values for inulin, sucrose, and raffinose were 11, 4.20, and 27.89 mM, respectively, and D -fructose was a competitive inhibitor (K i = 47.55 mM). The activation energies for sucrose, raffinose, and inulin were 10.4, 5.61, and 4.44 kcal/mol, respectively. The characteristics of A. terreus exoinulinase were compared to those of inulinases isolated from other organisms. The exoinulinase traits presented especially good thermostability and the ability to produce pure D -fructose, suggesting its application to the production of high-fructose syrup.Item Optimization of Endoglucanase and Xylanase activities from fusarium verticillioides for simultaneous saccharification and fermentation of sugarcane bagasse(Applied Biochemistry and Biotechnology, 2013-10-30) Almeida, Maíra N. de; Guimarães, Valéria M.; Falkoski, Daniel L.; Paes, Guilherme B. T.; Ribeiro Jr., José Ivo; Visser, Evan M.; Alfenas, Rafael F.; Pereira, Olinto L.; Rezende, Sebastião T. deEnzymatic hydrolysis is an important but expensive step in the production of ethanol from biomass. Thus, the production of efficient enzymatic cocktails is of great interest for this biotechnological application. The production of endoglucanase and xylanase activites from F. verticillioides were optimized in a factorial design (25) followed by a CCDR design. Endoglucanase and xylanase activities increased from 2.8 to 8.0 U/mL and from 13.4 to 114 U/mL, respectively. The optimal pH and temperature were determined for endoglucanase (5.6, 80 °C), cellobiase (5.6, 60 °C), FPase (6.0, 55 °C) and xylanase (7.0, 50 °C). The optimized crude extract was applied in saccharification and fermentation of sugarcane bagasse from which 9.7 g/L of ethanol was produced at an ethanol/biomass yield of 0.19.Item Direct ethanol production from glucose, xylose and sugarcane bagasse by the corn endophytic fungi Fusarium verticillioides and Acremonium zeae(Journal of Biotechnology, 2013-07-31) Almeida, Maíra N. de; Guimarães, Valéria M.; Falkoski, Daniel L.; Visser, Evan M.; Siqueira, Germano A.; Milagres, Adriane M.F.; Rezende, Sebastião T. deProduction of ethanol with two corn endophytic fungi, Fusarium verticillioides and Acremonium zeae, was studied. The yield of ethanol from glucose, xylose and a mixture of both sugars were 0.47, 0.46 and 0.50 g/g ethanol/sugar for F. verticillioides and 0.37, 0.39 and 0.48 g/g ethanol/sugar for A. zeae. Both fungi were able to co-ferment glucose and xylose. Ethanol production from 40 g/L of pre-treated sugarcane bagasse was 4.6 and 3.9 g/L for F. verticillioides and A. zeae, respectively, yielding 0.31 g/g of ethanol per consumed sugar. Both fungi studied were capable of co-fermenting glucose and xylose at high yields. Moreover, they were able to produce ethanol directly from lignocellulosic biomass, demonstrating to be suitable microorganisms for consolidated bioprocessing.