Yeast recycles performance in a cellulosic sugar cane hydrolysate media
Tuesday, April 29, 2014
Exhibit/Poster Hall, lower level (Hilton Clearwater Beach)
Vinicius F. Nunes Silva1, Simone Coelho Nakanishi1, S.R. Dionisio2, J. L. Ienczak2, Adilson R. Gonçalves1 and George Jackson de Moraes Rocha2, (1)Departamento de Biotecnologia, Escola de Engenharia de Lorena - Universidade de São Paulo, Lorena, Brazil, (2)Laboratório Nacional de Ciência e Tecnologia do Bioetanol – CTBE, Campinas - SP, Brazil
Cellulosic hydrolysate obtained by enzymatic saccharification of sugarcane bagasse pulp was submitted to an alcoholic fermentation by Saccharomyces cerevisiae Pe-2, strain provided by Pedra Agroindustrial Mill, Serrana-SP; Brazil. Firstly, the bagasse was pre-treated by H3PO4 1.5% (w/v) at 120ºC for 20 min followed by delignification employing NaOH 1.5% (w/v), 120ºC for 30 min, in a 350-L stainless steel-coated cast iron reactor, equipped with a stirrer, and heated through a jacket with thermal oil. After these processes, the material was hydrolyzate by commercial cellulase (15 FPU/g substrate) supplemented by β-glucosidase (10 UI/g substrate) in bottles containing 1L of medium under agitation in an orbital shaker at 150 rpm, 50ºC and 72h. Finally, the hydrolysate was concentrated until approximately 120 g.L-1 of glucose in a water bath at 100 °C. The yeast pre-inoculum was obtained from YPD medium in a 250 mL Erlenmeyer flask, containing 100 mL of medium under agitation at 200 rpm, 33°C, and 24h. The inoculum used was prepared with glucose (30 g.L-1), yeast extract (5.0 g.L-1), KH2PO4 (1.0 g.L-1), urea (5.0 g.L-1), KCl (1.0 g.L-1), CaCl2.2H2O (1.0 g.L-1), oligo-elements (1 ml.L-1) and thiamine (1 mg.L-1) under same conditions for pre-inoculum. Batch fermentations were performed, under cell recycle, in a bioreactor with 700 mL of working volume at 250 rpm and 33°C. Results showed a good performance of the yeast with the highest global productivity of 6.45 g.L-1.h-1 at fifth batch, yield of 87.4 %, and ethanol concentration of 47.1 g/L obtained from a cellulosic hydrolysate without sterilization.