Evaluation of sweet potato cultivars to the formation of sugars with potential for the production of ethanol

Abstract

Currently, the etanol production from renewable sources, such as starch or lignocellulosic materials has been extensively investigated. Aiming at creating viability to the production of alcohol from starch raw material, this study was an attempt to optimize the sweet potato hydrolysis employing commercial biocatalysts. The hydrolytic procedure was developed from 1 g to access Unicentro / Guarapuava / Agronomy 5 (UGA 5) at pH 5.6, 60 °C for 120 minutes. The enzymatic process evolution was evaluated as a function of different concentration combinations between the commercial enzymes α-amylase from Bacillus sp. and amyloglucosidase from Aspergillus Niger. In each test, the concentration of reducing sugars and glycose were determined. Aiming at the optimal operational, analysis of variance (ANOVA) was performed with a completely randomized design in a 2x5x5 full factorial. According to the interaction result presented by the ANOVA, it was seen that there is significant synergy between the enzymes in the generation of reducing sugars. The combination A3 revealed high conversion rate (0.96 ± 0.02 g) which was selected for the other accesses. The best conversion rates corresponded to the access UGA 56, in which 0.97 ± 0.03 g reducing sugars and 0.89 ± 0.02 g glycose were obtained. Despite this lowest productivity (t ha-1), this access indicating that this parameter is not enough to discriminate yield aiming at alcohol production.