Paving the whey - transforming dairy waste
Whey is the main by-product of the dairy processing sector. Teagasc researchers are collaborating with Munster Technological University (MTU), Ireland and Lund University, Sweden, to transform dairy waste into value-added and environmentally sustainable products.
Whey is rich in lactose, proteins and micronutrients. Due to this nutrient-rich profile, whey and residues derived from whey have a very high biological oxygen demand (BOD) and chemical oxygen demand (COD).
Unfortunately, high BOD and COD levels are extremely hazardous to the environment if disposed of directly into waterways or on land. As such, dairy waste streams derived from whey need to be treated before they can be discharged, this can prove expensive.
Believing there is a better solution for this dairy waste problem, Teagasc researchers partnered up with researchers from Ireland’s Munster Technological University (MTU) and Sweden’s Lund University. They have established the EBSTAR project. Through this project, the researchers are investigating the use of microbial bioprocessing technology to transform dairy residues. The focus is on transforming the underutilised acid whey and salted whey into renewable and valuable products.
Understanding the different types of whey-based waste streams
The project team aims to generate high-value bio-based products such as food additives, bioplastics and biogas from low-cost whey waste residues. They are using a unique multi-bioreactor biorefinery process.
Depending on the technology utilised, various types of whey are generated from the separation of casein from milk to make cheese. The two most common types of whey are sweet whey and acid whey.
Sweet whey
Sweet whey is generated from the production of most cheeses or casein products. The protein component of sweet whey is very valuable. It is used to produce:
- protein powders for infant nutrition
- sport performance-enhancing formulas
- food additives.
After the protein is extracted from the sweet whey, however, the remaining lactose-rich component is underutilised.
Acid whey
Acid whey is generated from the production of Greek yoghurt, cottage cheese and acid casein, and it has a sour-like taste. It is complex to process in contrast to sweet whey because it has a low pH which affects protein stability. It is also difficult to remove water from acid whey.
Salty whey
There is a third significant dairy by-product that also needs mentioning – salted whey. Salted whey is generated during the production of semi-hard and hard cheeses such as Cheddar. It contains between 4% and 10% salt depending on cheese type. This affects its potential to be further processed into value-added products.
To improve the yield of bio-based products from these waste streams, the project team are carrying out their work with the aid of innovative bioprocessing techniques. They are using novel microbial groups and an adaptive laboratory evolution approach.
Taking a circular bioeconomy approach
It has been recognised that the food sector needs to move away from an unsustainable linear model of production – or a ‘take, make and waste’ approach – to a more sustainable circular model. The goal is to reduce waste, the carbon footprint and the reliance on fossil fuels, all while helping to feed the rising world population.
Following a circular bioeconomy model – continuously producing value-added products and focusing on zero waste and pollution generation – is a major challenge for the dairy industry. The EBSTAR project is offering a potential solution for the dairy sector.
The EBSTAR project is offering a potential solution for the dairy sector. By harnessing the use of microbial fermentation technology to sustainably and efficiently biotransform low-cost materials such as whey-based waste streams into high-value bio-based products.
A life cycle sustainability assessment will be conducted on this bioprocess system as part of the project, to assess its environmental impact and establish hotspots for cost and emission reductions. The hope is that this work will demonstrate the potential broad applicability of a multi-bioreactor waste valorisation system for dairy manufacturers and other industries. Thus helping them to develop an economical and sustainable solution to making dairy waste residues commercially viable and renewable.
Figure 1. The EBSTAR biorefinery concept for acid whey and salted whey
80 to 190 million tonnes of salted whey and acid whey are generated annually.
9L of whey is generated per 1kg of cheese.
Funding
The EBSTAR project is funded by the Science Foundation Ireland Frontiers for the Future programme (ref. 19/FFP/6560). Brenda Barry is supported by the Teagasc Walsh Scholarship scheme (ref. 2019235).
Acknowledgements
The contributors wish to thank EBSTAR project partners Ed van Niel, Lund University and Micheal Callanan, Munster Technological University.
Contributors
Brenda Barry
MSc Walsh Scholar