title: Evaluation of sweet potato for fuel bioethanol production: hydrolysis and fermentation.
abstract: The enzymatic starch hydrolysis and bioethanol production from a variety of sweet potato developed for bioenergy purposes (K 9807.1) on the basis of its high starch yields, was studied. Drying at 55°C and 95°C of sweet potato neither affected the sugar content nor the starch enzymatic hydrolysis efficiency. Simultaneous saccharification and ethanol fermentations for dry matter ratio of sweet potato to water from 1:8 to 1:2 (w/v) were studied. Fresh sweet potato and dried at 55°C (flour) were assayed. At ratios of 1:8, similar results for fresh sweet potato and flour in terms of ethanol concentration (38-45 g/L), fermentation time (16 h) and sugar conversion (~ 100%) were found. At higher dry matter content, faster full conversion were observed using flour. A higher ratio than that for fresh sweet potato (1:2.2) did not improve the final ethanol concentration (100 g/L) and yields. High ethanol yields were found for VHG (very high gravity) conditions. The sweet potato used is an attractive raw matter for fuel ethanol, since up to 4800 L ethanol per hectare can be obtained.
authors.affiliation: Depto. Bioingeniería, Facultad de Ingeniería, Universidad de la República, J. Herrera y Reissig 565, CP 11300 Montevideo, Uruguay.
authors.forename: Claudia
authors.initials: C
authors.lastname: Lareo
authors.forename: Mario Daniel
authors.initials: MD
authors.lastname: Ferrari
authors.forename: Mairan
authors.initials: M
authors.lastname: Guigou
authors.forename: Lucía
authors.initials: L
authors.lastname: Fajardo
authors.forename: Valeria
authors.initials: V
authors.lastname: Larnaudie
authors.forename: María Belén
authors.initials: MB
authors.lastname: Ramírez
authors.forename: Jorge
authors.initials: J
authors.lastname: Martínez-Garreiro
keywords: Alcoholic fermentation; Bioethanol; Saccharomyces cerevisiae; Simultaneous saccharification and fermentation (SSF); Sweet potato