Milk to milk bottles: Sustainable polymer grade lactic acid from residual dairy lactose

点击翻译按钮获取中文摘要

In 2020, the value of the Canadian dairy market approached 15.9 billion$ with cheese as the main dairy product. Quebec alone produced close to 2 million tonnes of cheese whey (CW) in 2010. CW is mostly water (0.93 g/g) and lactose (0.05 g/g), with some protein, lipids, and minerals. Due to its high water content and low value, CW is exported (or discarded as waste). However, its organic loading represents an opportunity to produce biofuels and high-value specialty chemicals including biomonomers. Developing technologies to utilize CW will become a contributing factor to the economic health of the dairy industry as international treaties change the way it is exchanged among countries. Several separation technologies, e.g. nanofiltration and reverse osmosis, have been implemented to produce concentrated protein powder. However, lactose, a major constituent in the whey, is not yet utilized economically. Lactose, like other sugars, can be hydrolyzed and hydroxylated by an acid catalyst, to produce lactic acid. This project will explore several catalyst and reactor technologies to produce a 90 % lactic acid solution in water. This target is ideal to produce Polylactic acid - a biopolymer that sells for 3000 $/t. Together with the experimental objectives of developing the process, we will identify the economic incentive to produce 20 000 t/y: - Separation of lactose and proteins from the CW to produce 50 wt% concentrated lactose.- Around 96 % of the lactose present in the concentrated solution will be converted into glucose and galactose using catalytic hydrolysis with tin and zinc-based heterogeneous catalyst.- Dehydroxylate sugar to lactic acid over Lewis acid catalysts like Sn-beta zeolite.- Purify the final product by nanofiltration to separate sugars and vacuum evaporation.