Grantee Research Project Results
Final Report: Continuous Fermentation Bioprocess Resolving Food Waste Issues From Greek Yogurt Production
EPA Contract Number: 68HERC20C0040Title: Continuous Fermentation Bioprocess Resolving Food Waste Issues From Greek Yogurt Production
Investigators: Guzman, Juan J
Small Business: Capro-X Inc.
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2020 through August 31, 2020
Project Amount: $99,999
RFA: Small Business Innovation Research (SBIR) - Phase I (2020) RFA Text | Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR – Sustainable Materials Management
Description:
Capro-X is a sustainable biotechnology company focused on commercializing a patent-pending fermentation process, called the WheyAway system. The WheyAway introduces a solution for the dairy industry to upgrade processing waste streams from cheese and yogurt production into sustainable biochemicals, which we call bio-oil. Capro-X is currently focused on solving a key waste problem experienced by the entire Greek yogurt industry, where 3x more waste is produced than actual product. This waste, called acid whey, is expensively and unsustainably handled, and results in 300,000 gallons of fuel burned and 30,000 tons of GHGs being emitted annually in the US. The bio-oil produced by the WheyAway are direct replacements for fatty acids sourced from palm oil; the yielded bio-oil from 10% of the acid whey in NY state would eliminate the need for 5,000 acres of palm plantations. Today, Capro-X's bio-oils are traded as commodity specialty chemicals, largely utilized by the flavor and fragrance industry, and they are considered platform chemicals that are upgradeable to other specialty chemicals, as well as biofuel additives for diesel and jet fuel. In total, Capro-X will lower Greek yogurt customers expense and headache by providing WheyAways through treatment-as-a-service (TaaS) contracts. With TaaS contracts, Capro-X will handle acid whey from cradle-to-grave, and provide Greek yogurt customers with savings by returning earnings from bio-oil sales. The efforts undertaken in this project were focused on optimizing the biological conversion steps (fermentation) and the bio-oil extraction process to lower the operating and capital cost risks of scaling the WheyAway as the company proceeds with research and development to enter the market in 2022.
Capro-X proposed in this project to improve the commercialization potential for the WheyAway fermentation technology by:
- Lowering operating expense and increasing product yield by evaluating a novel bioreactor architecture.
- Lowering the capital expense of the costly bio-oil extraction system by optimizing operating conditions and chemistry selection.
- Attracting more bio-oil customers by employing food-grade oils in the bio-oil extraction system.
- Expanding addressable markets by evaluating whether both acid whey and cane sugar are amenable feedstocks.
In this project, Capro-X completed biotic and abiotic studies to optimize the WheyAway technology. We first compared the performance of the status quo bioreactor architecture (short and wide) to a novel bioreactor architecture (tall and narrow), which has been adapted to other waste treatment technologies, however, has never been evaluated for the WheyAway fermentation. The company evaluated different recirculation rates to identify optimal upflow velocities that could optimize the fermentation efficiency while lowering pumping energy costs. The company also operated a third bioreactor to evaluate upcycling acid whey with cane sugar into bio-oil. In total, the company attained about five months of continuous data from the three bioprocesses, including the key parameters of chemical oxygen demand (COD), acid/base consumption, bio-oil production/treatment (by gas chromatographer, GC), and sugar production/treatment (by high pressure liquid chromatographer, HPLC). Combining this data yielded a rich dataset providing a complete accounting of the efficiency of each step of the fermentation and bio-oil extraction process at the lab scale.
The abiotic study employed a new extraction system (pertraction) installed in a temperature-controlled enclosure. The company evaluated the impact of altering extractant chemicals by testing different concentrations of organic solvents and extractants. The company additionally performed preliminary evaluations of alternative organic solvents through batch bottle extraction tests with edible food-grade oils.
Summary/Accomplishments (Outputs/Outcomes):
Capro-X found that the novel tall bioreactor architecture outperformed the status quo short bioreactor (Figure 1). The tall reactor achieved a high carbon conversion efficiency (feed-to-product) of 65%, versus 45% from the short reactor. The tall reactor also achieved a carbon loss of only 14%, while the short reactor experienced 26% loss. To compound this impact, the tall bioreactor achieved its optimal performance at 25% of the recirculation rate of the short bioreactor, indicating further savings in operating expense by decreasing energy costs due to pumping. As a whole, tall bioreactor produced 37% more bio-oil than the short bioreactor.
The company successfully converted feedstock containing acid whey with cane sugar in a WheyAway bioprocess for the first time. In its optimal condition, a mixture of acid whey and cane sugar yielded a 68% carbon conversion efficiency, and a carbon loss of only 5%.
The extraction experiments demonstrated that the role of the extractant chemical was critical, and that there was a linear relationship between extraction rate and concentration in the organic solvent. Further, we observed that the current scale of the extraction system was nearly an order of magnitude oversized, which will lower capital costs significantly as the company scales. While using an organic solvent recycled from fryer oil led to record extraction rates, we have identified that the low selectivity would likely negatively affect the WheyAway bioprocess. Finally, batch bottle tests indicated that the current extractant chemicals outperformed all other candidates that we evaluated, however, some edible food-grade oils (like soy, grapeseed, sunflower, and rice bran) show great promise as alternatives for application in the pertraction system, but will require further evaluations.
Conclusions:
Capro-X successfully completed the aims of the proposed work by building and inoculating bioreactors, operating and implementing experimental changes, and performing abiotic extraction experiments. Below we outline the key outcomes from our work:
- The novel tall architecture considerably increased acid whey treatment and bio-oil production metrics.
- The tall architecture reactor obtained its highest performance at the ideal upflow velocity of 0.25x, minimizing the costs of pumping in the operating expense.
- Canee sugar is fully amenable to the WheyAway bioprocess alongside acid whey.
- Increased extractant concentration in organic solvent leads to increased extraction rates.
- The current extraction system is likely oversized by an order of magnitude, easing scaling requirements for future systems.
By factoring the results from this project into our existing technoeconomic model (Figure 1, accounting for all pumping, chemical addition, post-treatment, and heating costs combined into "Operating cost," as well as bio-oil revenues), the company found that a net increase of 148% could be envisions for future systems. This increasing the net income yields from the higher production of bio-oil from the tall bioreactor, and from a 13% decrease in pumping costs and 80% decrease in the cost of post-treatment of the effluent. Assuming Capro-X continues with the tall bioreactor architecture, we would expect a payback period of ~2 years; the short bioreactor, on the other hand, would have a payback period would be ~3 years.
Through the work accomplished in this EPA project, Capro-X is increasingly confident that the WheyAway bioprocess can be successfully commercialized to solve problematic waste streams experienced by dairy processors across the United States and the world. Key results that the tall bioreactor outperformed the current short architecture with higher bio-oil yield, lower pumping rates, and greater treatment extent indicate an operating expense savings of 20%, and an increase in bio-oil revenue of 59%, yielding a net income increase of 148%. Additionally, the finding that the extraction system can be downsized for future scale-up is highly valuable, as this system currently represents over a quarter of the capital cost. Finally, the discovery that the WheyAway is amenable to feedstocks containing both lactose and cane sugar expands the market opportunity by an order of magnitude. Previously, Capro-X was solely addressing the opportunity of commercializing to strained yogurt processors (Greek and skyr), with an estimated market size of $100MM. With the results from this EPA project, the company can address the waste treatment needs of any food production facilities that are manufacturing both dairy and sugary products at the same location (strained and unstrained yogurts, jams, shakes, syrups); yielding an estimated addressable market opportunity of up to $1,000MM.
SBIR Phase II:
Continuous Fermentation Bioprocess Resolving Food Waste Issues from Greek Yogurt Production | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.