SIMULATION OF THE BIOETHANOL PRODUCTION PROCESS FROM A MIXTURE OF GLUCOSE/XYLOSE INCLUDING TEMPREATURE, PH AND SUGAR CONCENTRATION EFFECTS

 

M.A. Camacho-Ruiz, R.M. Camacho-Ruiz, M. Armendariz, L. Ramirez-Velasco, A. Asaff-Torres, A. Levasseur, J.C. Mateos-Diaz, J.A. Rodriguez

 

 

The aim of this study was to investigate some carbohydrate esterases production from a filamentous fungus grown by solid state fermentation on corn bran as substrate, mixed with polyurethane as support (75:25, w:w), and its comparison with other agro-industrial by-products (wheat bran and coffee pulp) in the same conditions. Aspergillus niger, a known producer of feruloyl and other carbohydrate esterases, was used as fungal model. Cultures with corn bran induced a high production of feruloyl esterase type A and B activity: 5.27 and 0.66 U g-1 of dry matter over methyl ferulate and caffeate hydrolysis, respectively. Furthermore, in cultures with coffee pulp it is selectively induced the production of feruloyl esterase B activity compared to other by-products used. A zymographic analysis of extracts of cultures on corn and wheat bran revealed another enzyme, later identified as acetylxylan esterase A, capable to hydrolyze methyl hydroxycinnamates and p-nitrophenyl acetate. Activity on p-nitrophenyl acetate was 33.4 U g-1 of dry matter on cultures grown on corn bran. This work is the first report of high production of feruloyl and acetylxylan esterases using corn bran as substrate, which are enzymes of increasing biotechnological interest.