Milk to Milk Bottles: Milk bottles: Process for the Production of Durable Polymer Grade Lactic Acid from Residual Milk Lactose

In 2018, the value of dairy market approached 15 billion$ in Canada. However, every year the industry produces 1.76 billion liters of milk and whey permeate much of which is dried and sold as a low value animal feed. The close to ~40 kt/y of lactose in this stream represents an opportunity to produce biofuels and highvalue specialty chemicals including biomonomers. Developing technologies to utilize these solids will become a contributing factor to the economic health of the dairy industry as international treaties change the way it is exchanged among countries. Lactose, as other sugars, can be hydrolyzed and hydroxylated by an acid catalyst, to produce lactic acid. Lactic acid is an important chemical building-block in the food, cosmetics, chemicals, and pharmaceutical industries. It is a promising platform chemical for acrylic acid (2300 $/t), as monomer for polylactic acid, or for bulk biochemicals. The market of lactic acid is forecast to increase annually until 2026 by 11.5%. Lactic acid demand increases annually and is expected to reach around $13 billion by 2025. The price of lactic acid ranges between 1700 $/t to 3000 $/t. This project will explore catalytic and reactor technologies to produce polymer-grade lactic acid solution in water from whey permeate after proteins have been removed. This target is ideal to produce polylactic acid – a biopolymer that sells for 3000 $/t. Together with the experimental objectives of developing the process, wewill identify the economic incentive to produce 40 000 t/y lactic acid below 1800 $/t. The proposed process contains several steps:

• Around 96 % of the lactose present in the whey permeate after protein removal will be converted into glucose and galactose using catalytic hydrolysis with tin and zinc based heterogeneous catalyst.
• The concentrated sugar solution can be converted to lactic acid through dehydroxylation over a Lewis acid catalysts, such as Sn-beta zeolite, with sugar conversion of 99% and lactic acid yield of 66 % to 75 % at 150-200 °C.
• Several reactor technologies, such as fixed bed, fluidized bed, spinning disc, and ultrasonic reactors, will be applied to assess their potential for commercialization.

Together with dairy producers, biopolymer manufactures, and other stakeholders, technological pathways will be assessed during the development of the project to improve the feasibility of the process while meeting the expectations of the end users. There is an emerging societal desire that requires industry to develop technologies that are environmental, sustainable, and biosourced. The proposed process represents an efficient alternative to fermenation to convert lactose to lactic acid from dairy waste streams.