Acid pretreatment of foliage of Sweet Potato (Ipomoea batatas Lam. (L)) for efficient hydrolysis and biofuel production

Sweet potato (Ipomoea batatas) is a dicotyledonous plant that belongs to the family Convolvuceae. It is believed to have its center of origin in tropical America. Sweet potato was brought to Europe by Columbus and subsequently introduced to Africa and Asia by the Portuguese and Spanish traders. However, sweet potato is now cultivated wherever there is sufficient water to support its growth. Sweet potato has been considered a promising substrate for alcohol fermentation since it has a higher starch yield per unit land cultivated than grains. Sweet potato has several agronomic characteristics that determine its wide adaptation to marginal lands such as drought resistant, high multiplication rate and low degeneration of the propagation material, short grow cycle, low illness incidence and plagues, and covers rapidly the soil and therefore protects it from the erosive rains. The foliage of sweet potatoes was pretreated with sulfuric acid solutions at different temperatures and times. It was then analyzed the indices of sugars and inhibitors obtained liquor. It was observed that glucose ratios were high and the amount of generated 5-hydroxymethyl-2-furfural (HMF) from degradation of the monosaccharide is a strong function of the operation conditions, which have to be carefully chosen to minimize this inhibitor formation. On the other hand the concentrations of furfural and acetic acid were low for a large range of studied conditions.