Aproveitamento de biomassa residual lignocelulolítica da indústria de abate de bovinos para obtenção de bioetanol

Abstract

Due to search for alternative biomasses, that are low cost and high in cellulose concentration, for the production of 2nd generation ethanol - or lignocellulolytic - this study was carried out with the waste from the green line of slaughterhouse cattle, which is produced on a large scale in Brazil and in the State of Tocantins. The biggest challenge faced by companies of cattle slaughter is the large volume of waste that is generated, for instance, in the green line it includes cattle manure, vomiting, stomach contents, intestinal contents, residues of fat purification tank and others and these residues are mostly taken to incinerators or composting. This study, which was conducted at the Universidade Federal do Tocantins, in Palmas city – Tocantins state, aimed to determine the chemical composition of solid biomass from the filtration of all the liquid in the green line and the liquid biomass to evaluate its use in the lignocellulolytic ethanol production. The observed results have shown that the treated solid biomass waste had 57% cellulose, the solid biomass waste without pretreatment and the suspended solids had 30% and 27%, respectively. This demonstrates that the values obtained in laboratory tests were very close to what appears in literature for other residual biomass that were used as a source of cellulose for the production of 2nd generation ethanol. All the biomass were pretreated by autoclaving for 20 minutes at 121 ° C, but only the solid sample underwent a chemical pretreatment before the hydrolysis step. Also, the commercial cellulase enzyme: Cellic CTEC2 was used to carry the enzymatic hydrolysis. The amount of sugars in the sample was determined by HPLC (high-performance liquid chromatography) which has shown a hydrolysis yield of 0,22% for the liquid sample (Li), 2,67% for the solid sample without pretreatment (SI), 69,83% for the solid sample with pretreatment (SII) and 2,4% for the one with suspended solids (Ss). The concentration of ethanol for Li and Ss biomasses was not susceptible to detection by HPLC and the yield of ethanol to SII was 56%, which shows that it has the potential for bioethanol production.