VINASSE REUSE AS A DILUENT IN MOLASSES FERMENTATION: A STEP TOWARDS SUSTAINABILITY IN THE ETHANOL INDUSTRY

Abstract

Introduction:
Ethanol production from sugarcane generates significant by-products, particularly vinasse, which poses environmental challenges.
Objective:
To evaluate the use of vinasse as a diluent in molasses fermentation to reduce water consumption and enhance the sustainability of the ethanol production process.
Materials and Methods:
Molasses from the "Heriberto Duquesne" Sugar Agroindustrial Company in Villa Clara, Cuba, was used, and the vinasse was extracted from the distillation column. Five treatments were tested, with vinasse dilutions between 10% to 50%. Fermentations were conducted in duplicate and monitoring the brix and pH for 40 hours.
Results and Discussion:
The best fermentation efficiencies were achieved with 10% and 20% vinasse, resulting in 77.67% and 77.28% efficiencies, respectively. The highest vinasse concentrations resulted in a decrease in pH and lower ethanol production. The optimal vinasse recirculation rate was determined to be 18%, reaching an efficiency of 78.1%. This recirculation reduced water consumption by approximately 20%, which is equivalent to a daily saving of 13.7 m³ of fresh water.
Conclusions:
The study concludes that using vinasse as a diluent in molasses fermentation can reduce water usage without negatively affecting fermentation efficiency. It is feasible to replace up to 20% of water with vinasse for more sustainable ethanol production.