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

2020年，加拿大乳制品市场价值接近159亿加元，奶酪是主要乳制品。2010年，仅魁北克就生产了近200万吨奶酪乳清（CW）。CW主要是水（0.93 g/g）和乳糖（0.05 g/g），以及一些蛋白质，脂质和矿物质。 由于其高含水量和低价值，化学武器被出口（或作为废物丢弃）。然而，其有机负荷代表了生产生物燃料和高价值特种化学品（包括生物单体）的机会。随着国际条约改变了各国之间的交流方式，开发利用化学武器的技术将成为乳品业经济健康的一个促进因素。已经实施了几种分离技术，例如纳米过滤和反渗透，以生产浓缩蛋白粉。然而，乳清中的主要成分乳糖尚未被经济地利用。乳糖，像其他糖一样，可以通过酸催化剂水解和羟基化，以产生乳酸。该项目将探索几种催化剂和反应器技术，以生产90%的乳酸水溶液。这个目标是理想的生产聚乳酸-一种生物聚合物，售价为3000 $/t。 结合开发该工艺的实验目标，我们将确定生产20 000吨/年的经济激励：-从CW中分离乳糖和蛋白质，以生产50重量%的浓缩乳糖。使用锡和锌基多相催化剂的催化水解，浓缩溶液中存在的约96%的乳糖将转化为葡萄糖和半乳糖。在刘易斯酸催化剂（如Sn-β沸石）上将糖脱羟基为乳酸。通过纳米过滤分离糖和真空蒸发纯化最终产品。

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.