Many still and carbonated soft drinks contain high levels of refined sugar. Sugar in the UK has two possible origins: domestically produced from sugar beets or imported sugar from sugarcane. The fibrous sugarcane plant is rich in sucrose but also a large amount of starchy, wood-like material. After the sugar is extracted, a large mass of the cane plant is left over. These leftover by-products from sugar refining are known as bagasse.

Bagasse is rich in similar complex carbohydrate molecules as leftover parts of the corn plant. A strategy for the extraction of lactic acid from these carbohydrates, hemicellulose and cellulose, was outlined by a study led by the University of British Colombia. This study called for an enzymatic or microbial extraction of the carbohydrate followed by a sequential hydrolysis and fermentation reaction. This study also allowed costed projections for the production of lactic acid as the only product and with ethanol as a co-product. Both biorefineries also generate sufficient electricity to not only power and heat themselves but also to provide power back into the national grid, or go into powering the sugarcane refinery itself. Bagasse is traditionally used in boilers to create the heat and steam required to refine the sugarcane.

The calculated projections suggested that up to $180 million a year could be made from an initial total capital investment of $377.9 million in an industrial biorefinery. This would merit an Internal Rate of Return (IRR) 31.1%.

Alternatively, a biorefinery producing both ethanol and lactic acid could generate a combined sales revenue of $145.5 million, offering an IRR of 24.5% from a $369.9 million initial capital investment. These figures were calculated with an average yield of South African sugarcane plantations over the growing season.

Considering the chemical similarities between sugarcane and corn, this process could also be adapted for the conversion of corn to lactic acid.

IntelliDigest is a biotechnology company specialising in establishing innovative solutions for businesses in the food system, from farm-to-fork, to become more sustainable. Prioritising the elimination of edible food waste and the efficient upcycling of inedible food wastes back into the food system. We draw on our cutting-edge research, consulting, and training capabilities to address the global food sustainability challenges.

Sign up to the Global Food Loss and Waste Tracker to help reduce edible food waste and recover biochemicals and nutrients from inedible food waste to boost local food production. Contact us today to discuss how we can help your business create wealth from waste.