Bioconversion of Agave tequilana fructans by exo-inulinases from indigenous Aspergillus niger CH-A-2010 enhances ethanol production from raw Agave tequilana juice
Por:
Huitron, C, Perez, R, Gutierrez, L, Lappe, P, Petrosyan, P, Villegas, J, Aguilar, C, Rocha-Zavaleta, L, Blancas, A
Publicada:
1 ene 2013
Resumen:
Agave tequilana fructans are the source of fermentable sugars for the production of tequila. Fructans are processed by acid hydrolysis or by cooking in ovens at high temperature. Enzymatic hydrolysis is considered an alternative for the bioconversion of fructans. We previously described the isolation of Aspergillus niger CH-A-2010, an indigenous strain that produces extracellular inulinases. Here we evaluated the potential application of A. niger CH-A-2010 inulinases for the bioconversion of A. tequilana fructans, and its impact on the production of ethanol. Inulinases were analyzed by Western blotting and thin layer chromatography. Optimal pH and temperature conditions for inulinase activity were determined. The efficiency of A. niger CH-A-2010 inulinases was compared with commercial enzymes and with acid hydrolysis. The hydrolysates obtained were subsequently fermented by Saccharomyces cerevisiae to determine the efficiency of ethanol production. Results indicate that A. niger CH-A-2010 predominantly produces an exo-inulinase activity. Optimal inulinase activity occurred at pH 5.0 and 50 C. Hydrolysis of raw agave juice by CH-A-2010 inulinases yielded 33.5 g/l reducing sugars, compared with 27.3 g/l by Fructozyme® (Novozymes Corp, Bagsværd, Denmark) and 29.4 g/l by acid hydrolysis. After fermentation of hydrolysates, we observed that the conversion efficiency of sugars into ethanol was 97.5 % of the theoretical ethanol yield for enzymatically degraded agave juice, compared to 83.8 % for acid-hydrolyzed juice. These observations indicate that fructans from raw Agave tequilana juice can be efficiently hydrolyzed by using A. niger CH-A-2010 inulinases, and that this procedure impacts positively on the production of ethanol. © 2012 Society for Industrial Microbiology and Biotechnology.
Filiaciones:
Huitron, C:
Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Mol Biol & Biotechnol, Mexico City 04510, DF, Mexico
Perez, R:
Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Med Genom & Toxicol Ambiental, Inst Nacl Ciencias Med & Nutr Salvador Zubiran, Mexico City 14000, DF, Mexico
Gutierrez, L:
Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Mol Biol & Biotechnol, Mexico City 04510, DF, Mexico
Lappe, P:
Univ Nacl Autonoma Mexico, Dept Bot, Inst Biol, Mexico City 04510, DF, Mexico
Villegas, J:
Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Mol Biol & Biotechnol, Mexico City 04510, DF, Mexico
Aguilar, C:
Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Mol Biol & Biotechnol, Mexico City 04510, DF, Mexico
Rocha-Zavaleta, L:
Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Mol Biol & Biotechnol, Mexico City 04510, DF, Mexico
Blancas, A:
Univ Nacl Autonoma Mexico, Inst Invest Biomed, Dept Mol Biol & Biotechnol, Mexico City 04510, DF, Mexico
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