Maximizing second generation ethanol from biomass

Abstract

In recent years, there has been a growing national interest in fuel ethanol production due to its renewable nature. The conversion of biomass into ethanol has emerged as a globally researched and promising alternative, particularly in the fields of electricity generation and liquid biofuel production. Second generation ethanol is derived from lignocellulosic biomass, obtained through advanced chemical processes or biotechnology, through the conversion of cellulose into fermentable sugars. The aim of this work was to evaluate physical-chemical pre-treatments to hydrolyze sugarcane bagasse and subsequent alcoholic fermentation in the production of second-generation ethanol. Samples of sugarcane bagasse were washed, dried, suspended in acidic solution (1 and 0.1 M) or distilled water, and subjected to ultrasound and microwave treatment for varying exposure times ranging from 10 to 30 minutes. The materials were then filtered, washed, and fermented until reaching 1 °Brix. Distillation was performed after fermentation using a simple distiller. Prior to fermentation, samples were analyzed for reducing and total reducing sugars, as well as hydroxymethylfurfural, while alcohol content was measured post-fermentation. Treatments were conducted in four repetitions. The results showed that microwave pre-treatments with water or 0.1M acidic solution produced musts with higher sugar content, resulting in more alcoholic distillates. However, ultrasound was ineffective in sugar release, rendering alcoholic fermentation unfeasible. These findings underscore the critical role of selecting the appropriate pre-treatment method for achieving efficient second-generation ethanol production from lignocellulosic biomass.