Revaluation of agri-food waste to obtain bioethanol

Abstract

Objective: to produce bioethanol from the alcoholic fermentation of agri-food waste.Design/methodology/approach: food waste was collected for one month and separated into fruit and fabaceous waste; its size was reduced and then washed with hot acetone. A batch of 100 g of residue underwent acid hydrolysis with 5 %H 2 SO 4 at 125 °C, the hydrolysate was fermented with Saccharomyces cerevisiae at 30 °C for 48 h; the ferment was then distilled at 78 °C. The sugar content was determined following the phenol-sulfuric method. Brix degrees, density andpercentage w/w ethanol were measured with a densimeter.Results: from the fruit residues, an organic fraction was obtained with a total sugar content of 53.3 g/100 g of residue and 9.6 °Brix, generating 45 mL of distillate with 3.8 % w/w of bioethanol. From the fabaceae residues, an organic fraction was obtained with a total sugar content of 19.4 g and 4.140 °Brix, generating 30 mL of distillate with 2.54 % w/w of bioethanol.Study limitations/implications: Rapid decomposition of waste due to bacterial and fungal decomposition complicates long-term storage.Findings/conclusions: fermentable sugars can be obtained from the evaluated agri-food waste to obtain bioethanol. In this way, they can be integrated into the value chain as raw materials, reducing their accumulation and the environmental impact generated by their final disposal.