Whey Permeate As a Fuel and Energy Source
By virtue of its high carbohydrate content (approximately 75% of solids), whey permeate has been evaluated as a renewable energy source. Investigations have primarily focused on fermentations utilizing various phyla of yeast to produce bioethanol. However, other fuel sources including renewable diesel, biodiesel, hydrogen gas, and methane have been proposed and investigated. The gold standard for a wastewater stream such as whey permeate involves the mitigation of environmental impact, while adding value to the industry to make the process more cost-effective in all aspects. As evidenced by the cheese industry, each step in the process creates yet another waste stream. While cheese manufacturing produces whey and whey protein recovery produces whey permeate, the focus in the future must be on utilizing the total content of all by-product streams generated, with clean water as the ultimate effluent. Many technologies that propose to harvest the chemical energy from whey permeate as fuel advance this goal.