Ethanol Production from Cheese Whey

A Sustainable Solution for Waste Management


The increasing demand for sustainable practices in industries across the globe has fueled interest in producing biofuels from renewable resources. Cheese whey, a by-product of cheese manufacturing, has emerged as a promising resource for bioethanol production. With over 55 million tons of cheese whey produced annually in the European Union, managing its waste presents significant environmental challenges. This paper, written by Mattia Colacicco, Claudia De Micco, Stefano Macrelli, Gennaro Agrimi, Matty Janssen, Maurizio Bettiga and Isabella Pisano explores a recent study on the techno-economic feasibility of ethanol fermentation from cheese whey, using industrial-scale simulation.


Cheese Whey: An Environmental Concern


Cheese whey is a lactose-rich by-product of the cheese-making process. In 2020, Italy alone produced over 10 million tons of cheese whey, mostly from its northern regions like Lombardy and Emilia-Romagna. Previously discarded or used as fertilizer, cheese whey now requires more responsible disposal methods under modern environmental regulations. Due to its high biochemical and chemical oxygen demand (BOD and COD), its disposal is closely regulated to mitigate environmental impacts.


Waste-to-Resource: Ethanol from Cheese Whey


With advances in biofuel technology, cheese whey can now be processed to extract value from its rich nutrient profile. Bioethanol, produced through fermentation of the lactose found in cheese whey, offers a sustainable alternative to petroleum-based fuels. The study explores methods for treating cheese whey as feedstock for ethanol production using Kluyveromyces marxianus, a yeast strain well-suited for lactose fermentation.


The Process: From Filtration to Fermentation


The study simulated an industrial plant located in Apulia, Italy, with the capacity to proces 539 m³ of cheese whey per day, corresponding to half of the daily availability of the region. The model included three main stages:


  1. 1. Pretreatment via Membrane Filtration: This stage recovers whey protein concentrate (WPC) and isolates lactose for fermentation.
  2. 2. Fermentation and Ethanol Production: The lactose-rich fraction is fermented using Kluyveromyces marxianus to produce ethanol.
  3. 3. Waste Treatment and Energy Recovery: Anaerobic digestion processes organic residue, producing biogas that is converted into electricity and heat.


Through this process, other than ethanol, valuable by-products such as WPC and soil conditioners are produced, reducing waste and generating additional revenue.


Techno-Economic Assessment: Evaluating Feasibility

The study conducted a comprehensive techno-economic assessment (TEA) to evaluate the feasibility of the ethanol production process. Three different scenarios were modeled, with varying ethanol yields and lactose concentrations. The key metric used to assess economic viability was the Minimum Ethanol Selling Price (MESP).


  • Scenario 1 (S1): Ethanol yield of 0.48 g/g lactose, resulting in a MESP of 2.57 €/kg.
  • Scenario 2 (S2): Higher lactose concentration and a slightly lower yield of 0.35 g/g, lowering MESP to 1.88 €/kg.
  • Scenario 3 (S3): Optimized for higher yield (0.45 g/g), resulting in the most competitive MESP of 1.43 €/kg.


Sensitivity Analysis: Impact of Economic Factors

One of the study’s crucial findings is the sensitivity of the ethanol price to external economic factors. Several key parameters were analyzed to understand their influence on the final MESP:


  • Cheese Whey Pricing: The treatment of cheese whey as either a credit (through gate fees) or a cost (as a raw material) had a significant impact on MESPs. Gate fees, which are region mandated fees that pay companies to handle waste, could bring ethanol prices below market values, especially in S2 and S3.

  • Equipment Purchase cost: The cost associated with the purchase, building and installation of the equipment, especially fermentors, had an important impact on MESPs. A slight lowering in purchase price could bring the MESPs to a competitive level.  

  • Energy and Utilities Costs: The energy required for processing cheese whey into ethanol is another critical factor. The model highlighted how a facility’s reliance on grid electricity or its ability to generate energy internally (via biogas) could affect overall production costs.

Through scenario analysis, the study showed that integrating cheese whey treatment into existing dairy processes could further reduce costs, especially when combined with favorable policies like gate fees for whey disposal.


Sustainability Benefits: Beyond Ethanol

The study also emphasized the environmental benefits of bioethanol production from cheese whey. By converting waste into valuable products, this process aligns with circular economy principles, reducing the environmental burden on water bodies and promoting renewable energy sources.


Energy Generation: The biogas generated during the process was used to produce electricity, reducing the plant’s dependence on external energy sources.


By-Products: Apart from ethanol, the process also produces whey protein concentrate (WPC) and soil conditioners, further contributing to sustainability and economic feasibility.


Challenges and Future Outlook

While the findings are promising, several challenges remain in scaling this technology for widespread adoption. High initial capital and maintenance costs for fermentation and treatment units significantly impact overall feasibility. The study also highlighted the critical role of policy support, particularly in regions where gate fees can make or break the economic viability of bioethanol production.


Additionally, further research aimed tooptimizing the fermentation process for higher ethanol yields along with exploring co-digestion strategies with other organic waste, could improve the economic returns of bioethanol production from cheese whey.


Conclusion: The Path Forward for Cheese Whey Ethanol Production

The production of ethanol from cheese whey provides a dual benefit: effective waste management and a viable pathway for renewable energy production. With techno-economic analyses indicating competitive ethanol pricing in optimized scenarios, the potential for scaling up this process is evident. However, economic feasibility remains closely tied to policy frameworks that support waste valorization through mechanisms like gate fees and energy credits. As industries and governments continue to prioritize sustainability, bioethanol from cheese whey could become a cornerstone of the biofuel industry.


This text is an excerpt from an article published under the following reference: “Colacicco, M., De Micco, C., Macrelli, S. et al. Process scale-up simulation and techno-economic assessment of ethanol fermentation from cheese whey. Biotechnol Biofuels 17, 124 (2024)”

The text can be read in full at this link. Want to learn more about the circular economy and its issues? Visit Tondo’s blog!

Isabella Pisano

Isabella Pisano holds a degree in Chemistry and Pharmaceutical Technology and a PhD in Cellular Biochemistry and Pharmacology from the University of Bari in 2004. After a period of study and research in Italy and abroad on model systems in yeast of mitochondrial diseases, she has been a researcher in Chemistry of Fermentations (CHIM/11) at the Department of Biosciences, Biotechnology and Enviro... Read more

Isabella Pisano holds a degree in Chemistry and Pharmaceutical Technology and a PhD in Cellular Biochemistry and Pharmacology from the University of Bari in 2004. After a period of study and research in Italy and abroad on model systems in yeast of mitochondrial diseases, she has been a researcher in Chemistry of Fermentations (CHIM/11) at the Department of Biosciences, Biotechnology and Environment of the University of Bari Aldo Moro since 2008. For the past 15 years she has been a lecturer at the three-year and master’s degree courses in Biotechnology at the University of Bari teaching “Industrial Microbiology,” “Biotechnology of Fermentations,” and for the past 2 years “Biorefineries.” Since 2022, he has held the course in “Chemistry of Industrial Fermentations” as part of the newly established master’s degree program in Industrial Chemistry.

Her research activities are based on the development of new models of biorefineries for the valorization of agro-industrial wastes through integrated approaches of microbial biotechnology, chemoenzymatic transformations and green chemical-physical methods. She holds 5 national and international patents and is Principal Investigator of several industrial research projects in collaboration with biotech or green chemistry companies. Isabella Pisano is a Tutor Lecturer of several industrial PhDs and is also a member of the scientific committee and mentor of several start-ups, companies and public-private partnerships. For the past 5 years, she has been the Third Mission Delegate for the Department of Biosciences, Biotechnology and Environment. Since 2023, she has been the President of the University Center of Excellence for Sustainability on behalf of the Rector of the University of Bari.

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