Açai Seeds ( Euterpe oleracea Mart) Are Agroindustrial Waste with High Potential to Produce Low-Cost Substrates after Acid Hydrolysis.

Açai seeds have been discarded improperly around the Amazonia region, but they can be seen as promising low-cost substrates for fermentation processes. The structural carbohydrates and physicochemical characterization of açai seeds from the Amazonia were assessed followed by the determination of the optimal hydrolysis conditions using H 3 PO 4 (phosphoric acid) and H 2 SO 4 (sulfuric acid) to obtain a liquor with high contents of simple carbohydrates and low levels of potential microbial inhibitors usually generated during acid hydrolysis of carbohydrates. A central composite rotational design was carried out varying the concentrations of diluted acid (0-5%, w / v ), solids (0.1-25%, w / v ), and hydrolysis time (9.5-110 min). Acid hydrolysis with H 2 SO 4 was more effective in producing reducing sugars (15.9-103.1 g/L) than H 3 PO 4 (2.9-33.9 g/L) during optimization. The optimal hydrolysis conditions with H 2 SO 4 were 3.5% of acid ( w / v ), 25% of solids during 70 min at 121 °C, which provided a liquor with 55 g/L of reducing sugars and low levels of microbial inhibitors: acetic acid (1.8 g/L), hydroxymethyl furfural (338 mg/L), and furfural (10 mg/L). Thus, açai seeds were characterized as promising agroindustrial waste with high potential to be used as a low-cost substrate in biotechnological processes, comprising relevant environmental and bioeconomic aspects for the development of the Amazonia.