Re-Use: From Vineyard Waste to Biofuel; Wineries Have Multiple Uses

University of Adelaide researchers found that a ton of solid waste from grapes could be used to produce up to 400 liters of biofuel. This brings a whole new meaning to reuse.

"This is a potentially economic use for what is largely a waste product," Rachel Burton, associate professor and program leader with the Australian Research Council (ARC) Centre of Excellence in Plant Cell Walls in the School of Agriculture, Food and Wine, said in a statement.

Since global wine production produces roughly 13 million tons of grape marc waste -- from skins, pulp, seeds and stems -- each year, according to the release, taking that waste and fermenting it to make bioethanol could greatly reduce something that otherwise requires disposal.

Kendall Corbin, a PhD candidate at the University of Adelaide, analyzed the composition of grape marc from cabernet sauvignon and sauvignon blanc and investigated pre-treatment of the grape marc with acid and enzymes. Her study, recently published in Bioresource Technology, found that ethanol could be produced by fermenting the majority of the carbohydrates found in grape marc. This production was found to yield up to 270 liters per ton of grape marc. Corbin noted that these ethanol yields could be increased by pre-treatment with acid and enzymes up to 400 liters a ton. Any additional product left over from the grape waste was also found to be suitable for animal feed or fertilizer.

"Using plant biomass for the production of liquid biofuels can be difficult because of its structurally complex nature that is not always easily broken down," Corbin said in a statement. "Grape marc is readily available, can be sourced cheaply and is rich in the type of carbohydrates that are easily fermented."

Burton added in the statement that, "We've shown that there is a potential new industry with the evolution of local biofuel processing plants to add value to the grape for an environmentally friendly biofuel."

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