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.

Alcohol production from sweet potato (Ipomoea batatas (L.) Lam.) genotypes in fermentative medium

“…Despite having a higher use of maize (Zea mays L.) as raw material for fuel production, it shows adaptation problems to certain climatic conditions, low energy balance values, besides competing directly with food chain (Lareo et al, 2013).…”

“…Currently, main biofuels with the capacity to replace fuels derived from petroleum are obtained from plant biomass like biodiesel and ethanol. In this way, the study and improvement of raw materials is essential for the consolidation of biofuels in the world energy matrix (Silveira, 2008;Loyola, Urra & Acuña, 2016;Lareo, Ferrari, Guigou, Fajardo, Larnaudie, Ramírez & Martínez-Garreiro, 2013). …”

Batata-doce [<i>Ipomoea batatas</i> (L.) Lam.] nas roças e quintais do litoral paulista: diversidade genética morfoagronômica, com base em morfometria geométrica, descritores e produção de bioetanol

“…A batata-doce tem sido considerada como um substrato promissor para a produção de bioetanol, devido à sua elevada produção de amido por unidade de área cultivada quando comparada com outras culturas (ZISKA et al, 2009;SRICHUWONG et al, 2012;DUVERNAY;CHINN;YENCHO, 2013;LAREO et al, 2013). De acordo com Taborda et al (2015), a comparação do desempenho na produção de etanol em várias culturas mostra que a batata-doce apresenta potencial, com rendimento de 2.496 litros por hectare (Tabela 1.1).…”

“…Unidos (ZISKA et al, 2009;SANTA-MARIA et al, 2011;DUVERNAY;CHINN;YENCHO, 2013), no Uruguai (FERRARI; GUIGOU; LAREO et al, 2013) e na Itália (MONTEFUSCO et al, 2014).…”

“…Vários estudos vêm sendo desenvolvidos para explorar o potencial de produção do bioetanol da cultura da batata-doce no Brasil (GONÇALVES NETO et al, 2011;MARTINS et al, 2012;SILVEIRA, 2008;TABORDA et al, 2015), na China (CAO et al, 2011;WANG et al, 2013), nos Estados Unidos (DUVERNAY; CHINN; YENCHO, 2013;SANTA-MARIA et al, 2011;ZISKA et al, 2009), no Uruguai (FERRARI;LAREO et al, 2013) e na Itália (MONTEFUSCO et al, 2014).…”