Recovery of Valuable Compounds from Distillery Vinasse: Trials for Plant Scale-Up

Wine lees is a semi-solid suspension rich in yeast cells, representing a winemaking by-product that is rarely valorized after distillation. This study focuses on the exploitation of yeast-containing vinasse resulting after wine lees distillation by proposing optimized thermal extractions that can be potentially integrated with the current wine lees distillation workflow. Vinasse with different solids concentrations (10, 30, 50%) were treated at different temperatures (104, 108, 112 °C) and durations (20, 40, 60 min) using a pressure cooker device. The release of proteins, polysaccharides, and oligosaccharides from these pressure-assisted lab extractions were compared with that in untreated vinasse and vinasse treated with a previously proposed autoclave method. The resulting extraction appears to be generally preferable to the autoclave, which would require higher costs for energy and equipment. The obtained extraction process significantly enhanced the recovery of total proteins, oligosaccharides, and medium- to low-molecular-weight polysaccharides. Conversely, all heat treatments reduced the extraction of high-molecular-weight polysaccharides, indicating that these compounds should be directly extracted from untreated vinasse. These outcomes, along with the study of samples’ viscosity, density, and specific heat, allowed us to propose an integrated extraction plant set up that includes a crossflow filter and an industrial cooker. This set up aims to maximize the extraction of each valuable fraction, thereby better exploiting vinasse following a biorefinery approach.