Professors in the Faculty of Science continue to distinguish themselves by developing new and innovative technologies, often in partnership with local companies and with the excellent assistance of graduate and undergraduate students. An ongoing collaboration between Professors Allyson MacLean and Alexandre Poulain, and Almonte-based Dairy Distillery, has led to major innovation in both alcohol and fertilizer production and while being conscious of the environment by recycling dairy waste.
The dairy industry uses ultrafiltration to filter milk and create the beverage that we drink. This filtration technique employs pressure or concentration gradients to separate a solution through a semipermeable membrane. During the filtration process, lactose, vitamins, and minerals (collectively called permeate) are separated from the milk protein and fat. Unused in the milk we drink, the sugar-rich milk permeate is considered as waste to the dairy industry and is consequently discarded. Yet, one person’s trash is another’s treasure.
Dairy Distillery, founded in 2018, is an innovative company based in Almonte, Ontario, that focuses on producing low carbon ethanol from dairy waste. In collaboration with Dairy Distillery, Prof. Poulain identified a microorganism that could ferment milk permeate to create ethanol. After purifying that ethanol, Dairy Distillery uses it to make alcoholic beverages such as vodka and cream liqueur, and even hand sanitizer that was distributed to Ottawa hospitals during the pandemic. Building on this success, they envisage getting into bioethanol (biofuels); i.e., making ethanol for use as gasoline.
Fermenting milk permeate to produce ethanol creates yet another waste product called distillery stillage. This stillage contains secondary yeast metabolites, yeast cells, and is typically rich in nutrients and major ions. With the growth of Dairy Distillery comes the production and accumulation of increased amounts of this waste product.
To turn this distillery stillage into a fertilizer that can help plants grow more efficiently, Prof. Poulain and Dairy Distillery invited Prof. MacLean, a plant biologist, to their collaborative endeavour. Fertilizer contains nitrogen, potassium and phosphorus, essential minerals for plants’ growth. The distillery stillage, which is rich in phosphorus and potassium, appeared as an ideal fertilizer candidate. Funded by the joint National Sciences and Engineering Research Council of Canada (NSERC) Alliance - Ontario Centre of Innovation (OCI)- Collaborate 2 Commercialize program, this ambitious project consisted of reformulating the stillage waste to transform it into an efficient fertilizer, thus diverting it from the waste stream into a useful resource.
As the project progressed, Prof. MacLean and her students trialed the fertilizer on different edible crops such as cucumbers, tomatoes, and peppers. Using control groups (water only), conventional fertilizer (miracle grow) and Dairy Distillery stillage, they confirmed that stillage is excellent at promoting the growth of plants. During the summer 2022, Prof. MacLean’s team even applied stillage on uOttawa’s main campus to demonstrate the success of their fertilizer, using a cleared area on the STEM complex lawn that they seeded with grass. While one patch was watered only with water, the other was nourished with the stillage-based fertilizer. By mid-summer, the grass receiving the experimental fertilizer showed significant growth compared to the grass receiving water only.
Many questions remain about the potential advantages of applying stillage fertilizer to enhance plant growth. One of the most important questions that remains to be addressed is whether the stillage-based fertilizer acts directly to stimulate plant growth or whether it fosters a beneficial proliferation of the plant microbiome by supplementing the soil with much-needed nutrients, which subsequently benefits plant growth. Quite possibly, both mechanisms might apply!
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