A produção de etanol como alternativa para o aproveitamento da quirera de arroz

Abstract

Ethanol has been a fuel of great strategic importance for Brazil since the 1970s when the first program to encourage the production and consumption of this fuel was launched, PROALCOOL (Programa Nacional do Álcool). Since then, the search for new feedstocks and technologies to produce ethanol is necessary given that the fact that environmental issues have increasingly given solidity to the production of renewable fuels. The paddy production chain, from production to milling, generates large volumes of waste, such as husk, brokens (Quirera) and bran. The present work aimed to evaluate the yields of the conversion of starch into assimilable sugars and to infer on the economic viability of the production of ethanol from the use of the rice residues (brokens). The samples were obtained from a rice processing industry and immediately submitted to drying at 70 oC until constant weight and obtained their humidity, later crushed in a knife mill and separated in 1 mm opening sieves. The first evaluations were chemical-bromatological analyzes by determining the levels of ash, crude protein, ether extract, total fibers and total carbohydrates. The hydrolysis of starch was carried out with the enzymes alpha-amylase and Amyloglucosidase. The brokens (Quirera) showed the following results: 7.85; 1.56; 0.74; 5.54 and 84.21% for protein, ether extract, ash, total fiber and total carbohydrate contents, respectively. The hydrolysis yield was 90.67% and the conversion of reducing sugars from the sample was 76.34 g.100g-1. The production of ethanol from the rice residues was economically viable when used for its own supply.