Wine waste turned into biofuels

Wine just got even better for you as Australian researchers have developed a technique for converting winery waste into compounds that could have potential value as biofuels or medicines.

Avinash Karpe is quite pleased with his discovery.

Avinash Karpe, a PhD student at Swinburne University of Technology in Melbourne, has worked out how to turn wine waste into compounds that can be used to create ethanol and other biofuels by using fungi to break it down.

According to Karpe: “Various fungi are known to degrade this waste by generating an array of enzymes.”

“These enzymes convert the waste to soluble sugars which can then be converted into other products,” said Karpe.

As part of his PhD research, Karpe had been investigating how to break down this woody material composed of cellulose, pectins and lignins into simpler compounds that can be used to create other things such as ethanol or other biofuels.

He performed a series of experiments to develop the best procedure for degrading winery biomass waste and discovered that a 30-minute heat activated pretreatment aided the breakdown of these biomolecules.

Formerly of little use, grape must waste could now have practical applications.

Using a ‘cocktail’ of four fungi – Trichoderma harzianum, Aspergillus niger, Penicillium chrysogenum and Penicillium citrinum, in a one litre bioreactor, Karpe succeeded in breaking down the biomass.

“We have demonstrated this technique in the laboratory, but this process can be scaled up to an industrial scale,” said Professor Enzo Palombo, Chair of Swinburne’s Department of Chemistry and Biotechnology.

Australia is the world’s sixth largest wine producer, with around 1.75 million tonnes of grapes crushed for wine every year.

After the final pressing, more than half of the grapes crushed end up as biomass waste comprised of skins, pulp, stalks and seeds.

Unlike other agricultural by-products, this waste has limited use as animal feed due to its poor nutrient value and digestibility.

It is also not suitable as compost because it doesn’t degrade. Thus a majority of this grape waste ends up as toxic landfill, but this could soon change.