AsianScientist (Sep. 7, 2017) – Scientists in Singapore have invented a process to turn spent brewery grains into a valuable product that can grow beer yeast. The published their findings in the journal AMB Express.
In beer making, yeast is the key ingredient for fermentation, a process where sugars from the grains are converted into alcohol. The beer brewing process thus requires large amounts of yeast. When grains such as barley or hops are fermented by yeast, the grain’s sugars, protein and nutrients will be stripped, leaving behind plant fibres known as lignin.
While lignin is tough and generally unusable in food production, certain types of microorganisms are able to break lignin down into smaller, nutritious pieces. These nutritious pieces can then be mashed and turned into a liquid, which are easily digestible by yeast.
Spent grain amounts to as much as 85 percent of a brewery’s waste and is often used as compost or for animal feed. Innovative approaches to extract value and re-use these discards are thus actively sought by the beer industry.
In this study, scientists from Nanyang Technological University, have found a way to recycle spent brewery grains. Professor William Chen, Director of NTU’s Food Science and Technology Program, who led the research, said the new conversion process turns brewer’s waste into a valuable liquid nutrient. Similar commercial liquid nutrients are sold for US$30 per liter, whereas the team’s upcycled liquid nutrient is produced at only a fraction of the cost.
“We have developed a way to use food-grade microorganisms to convert the spent grains into basic nutrients that can be easily consumed by yeast,” explained Chen. “About 85 percent of the waste in brewing beer can now be turned into a valuable resource, helping breweries to reduce waste and production cost while becoming more self-sustainable.”
This waste-to-nutrient technology took Chen and Ms. Sachindra Cooray, a PhD student in his lab, two years to develop. The innovation has drawn the interest of several international beverage companies, including Asia Pacific Breweries in Singapore, and Chen is in talks with several companies to license or commercialize the proprietary technology.
Associate Professor Xu Rong, Interim Chair of the School of Chemical and Biomedical Engineering, said the burgeoning global population increasingly strains conventional food sources, so there is a need to innovate new foods and processes to alleviate the increasing demand.
“Discovering new uses for different types of natural food grade microbes in waste-to-nutrient technology is the latest breakthrough by NTU chemical and bioengineers, which can help to address the food security issues currently faced by the world,” said Xu.
“By upcycling waste to usable nutrients, conventional resources used to grow yeast can now be diverted into the production of wholesome foods,” she added.
The article can be found at: Cooray et al. (2017) Evaluation of Brewers’ Spent Grain as a Novel Media for Yeast Growth.
Source: Nanyang Technological University.
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