Progress 10/01/17 to 09/30/18
Outputs
Target Audience:The main target audience for this project is represented by dairy processors in NYS, particularly Greek yogurt manufacturers, dairy farmers, animal feed companies, as well as wastewater treatment consulting firms that might benefit from the conversion of acid whey waste into a green antimicrobial that can be used as a growth promoter for animals at NYS farms. A good understanding of the composition and value added utilization of Greek yogurt acid whey, particularly its conversion into caproic acid oil, will help the economic bottom line of Geek yogurt companies and wastewater treatment consulting firms, by converting a waste stream into a resource. Target audiences are also dairy and food scientists and scientists who develop new bacterial cultures (open cultures or reactor microbiomes) for resource recovery. Changes/Problems:As a bonus to the originally proposed plan of work, we have developed a processing approach to concentrate acid whey using a combination of reverse osmosis and forward osmosis, which allowed us to increase the solids in whey from ~6% to ~ 45%, without any detrimental changes to the product quality. This allows a longer term storage of acid whey and also the volume of acid whey that needs to be stored and transported before conversion into MCCAs or other compounds. What opportunities for training and professional development has the project provided?A postdoctoral associate and a Phd student were trained as part of the project. They also participated in professional development activities, such as symposia and conferences. How have the results been disseminated to communities of interest?Information was provided to the scientific community and industry representatives both during conferences and in direct conversations. We have also informed NYS Greek yogurt industry and regulatory agencies about acid whey processing technologies and approaches as part of an Acid whey symposium organized at Cornell in August 2018, which had over 50 participants from academia, industry and regulatory agencies. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
As part of this project we have: 1. Determined the composition and concentration of iacid whey from several NYS Greek yogurt plants. 2. Performed month-long anaerobic bottle tests with a microbiome inoculum to produce dissolved n-caproate. 3. a) Conducted a long-term bioreactor study with product extraction and separation that produced n-caproic acid oil. Specifically, we demonstrated that a temperature-phased anaerobic bioprocess can convert acid whey from Greek-yogurt production into medium-chain carboxylic acids (MCCAs). Thermophilic and mildly acidic conditions in the first phase promoted aLactobacillus spp.-dominated microbiome that converted sugars from acid whey into lactic acid. The lactic acid-rich effluent was then fed to a mesophilic second phase in which a more diverse microbiome performed chain elongation to produce MCCAs. The overall SCOD conversion efficiency for acid-wheyconversion into MCCAs was 53.5%. b) We have also explored a processing approach to concentrate acid whey, thus allowing its longer term storage followed by later conversion into MCCAs. This processing approach consisted in a combination of membrane processes (reverse osmosis and forward osmosis), which allowed us to increase the solids in whey from ~6% to ~ 45%, without any detrimental changes to the product quality. 4. Informed NYS Greek yogurt industry and regulatory agencies about whey processing technologies as part of an Acid whey symposium organized at Cornell.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Menchik P. and Moraru C.I. 2018. Concentration of acid whey from Greek-style yogurt using a combination of reverse osmosis and forward osmosis. ADSA Annual Meeting, Nashville, TN. June 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Angenent L. 2018. Conversion of acid whey into medium-chain carboxylic acid bio-oil with reactor microbiomes. Whey and Dairy Co-Products Symposium. Cornell University, Ithaca, NY, USA. August 13, 2018
- Type:
Other
Status:
Published
Year Published:
2018
Citation:
Menchik P., Zuber T., Zuber A. and Moraru C.I. 2018. The acid whey conundrum. Dairy Foods Magazine April, 2018, p. 41-43
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:The Greek yogurt companies in NYS, farmers, veterinarians, and animal feed companies; and wastewater treatment consulting firms are target audiences for the outcome of the conversion of acid whey waste into a green antimicrobial that can be used as a growth promoter for animals at NYS farms. Since acid whey can be converted with a mixed bacterial culture into caproic acid oil, this would help the Geek yogurt companies together with wastewater treatment consulting firms to change and fund their wastewater treatment systems into a resource recovery system. Target audiences are also scientists, who work with undefined mixed cultures (open cultures or reactor microbiomes) for resource recovery. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A postdoctoral associate was trained as part of the project. The postdoc also participated in professional development activities, such as conferences. How have the results been disseminated to communities of interest?Information was provided to the scientific community and industry representatives both during conferences and in direct communications. What do you plan to do during the next reporting period to accomplish the goals?Evaluate methods to concentrate acid whey, which may improve the yield of converting acid whey into valuable compounds.
Impacts
What was accomplished under these goals?
We demonstrated that a temperature-phased anaerobic bioprocess can convert acid whey from Greek-yogurt production into valuable medium-chain carboxylic acids (MCCAs). Thermophilic and mildly acidic conditions in the first phase promoted a Lactobacillus spp.-dominated microbiome that converted sugars from acid whey into lactic acid. The lactic acid-rich effluent was then fed to a mesophilic second phase in which a more diverse microbiome performed chain elongation to produce MCCAs. The overall SCOD conversion efficiency for acid-whey conversion into MCCAs was 53.5%.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Jiajie Xu, Jiuxiao Hao, Juan J.L.
Guzman, Catherine M. Spirito, Lauren A. Harroff, Largus T.
Angenent. 2018. Temperature-Phased Conversion of Acid Whey Waste Into Medium-Chain Carboxylic Acids via Lactic Acid: No External e-Donor. Joule 2, 116
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Progress 10/08/15 to 09/30/16
Outputs
Target Audience:The Greek yogurt companies in NYS, such as Fage, Chobani, Byrne Dairy, and many others; farmers, veterinarians, and animal feed companies; and wastewater treatment consulting firms are target audiences for the outcome of the conversion of acid whey waste into a green antimicrobial that can be used as a growth promoter for animals at NYS farms. One of our conclusions already is that acid whey can be converted with a mixed bacterial culture into caproic acid oil. This would help the Geek yogurt companies together with wastewater treatment consulting firms to change and fund their wastewater treatment systems into a resource recovery system with a valuable product proposition. For farmers an opportunity exists to mix in the caproic acid oil as an alternative for antibiotic growth promoters. The use of antibiotics in animal feeds is being criticized for the emergence of antibiotic resistance in the US population. Of course, the animal feed companies would need to be involved in developing the animal feed rations with our oil to be sold to the NYS farmers. Finally, target audiences are also scientists, who work with undefined mixed cultures (open cultures or reactor microbiomes) for resource recovery. In the coming year, we will publish a research paper with the results to help the field move forward and to unravel knowledge on the open cultures of microbial consortia (in addition to presenting at conferences). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Post-doc training Dr. Jiajie Xu (funded through the DEC grant, not yet by Hatch) Scientific staff training: Dr. Hanno Richter (he spend 4.5 month out of 12 month on this project studying the pathways and advising Jiajie). How have the results been disseminated to communities of interest?We have not yet shared results with researchers and others because work is in progress. What do you plan to do during the next reporting period to accomplish the goals?In addition to the performance results that we are currently generating, we will focus on the microbial ecology tools to further understand the microbial community dynamics during the conversion in both bioreactors. We plan to submit our manuscript this year and will disseminate information to players in the Northeast. We will also share our results at the international resource recovery conference in New York City on August 5-9, 2017.
Impacts
What was accomplished under these goals?
We propose to convert acid whey into the valuable product caproic acid oil and methane gas at the waste processing plant of Greek yogurt plants. Caproic acid oil is added to animal feed as a green antimicrobial and as a replacement for growth-promoting antibiotics, which are already banned in Europe. Methane is utilized as a biofuel carrier in industry boilers. Our proposed research would, therefore, ensure not only an economic incentive for Greek yogurt plants in NYS and will make them more competitive, but also: (1) generate an important new green product for agriculture; and (2) reduce the need for nonrenewable fuels at the yogurt plant and for trucking. We have organized the outputs of this report based on the four objectives with which we started this project: Objective 1. Determine the composition and concentration of individual organic compounds in acid whey and process waste streams from three different NYS Greek yogurt plants. We have completed this objective for three acid whey samples from two different Greek yogurt plants and found the acid whey streams to be similar in composition, making a third plant sampling event not necessary because this would not further change the knowledge base. We measured the concentrations of the carbon-based compounds, such as lactose, fructose, lactic acid, carboxylic acids, total and soluble chemical oxygen demand (COD), because these will be converted into caproic acid oil. Here, we report only lactose, fructose, and lactic acid, respectively: Fage 02/17/2015: 95, 31, and 130 mM; Fage 10/21/2015: 98, 32, 135 mM; and Byrne Dairy 05/09/2016: 110, 37, and 152 mM. We did not know that the differences would be relatively small and also did not know the sugar contents. Objective 2. Perform month-long anaerobic bottle tests with a microbiome inoculum to produce dissolved n-caproate. We prepared small serum bottle with acid whey with an acclimated biomass that had been producing n-caproic acid from a different substrate and found n-caproic acid production from acid whey. The production was obviously limited by the accumulation of this acid since it is inhibiting at higher concentrations, but the bottle studies showed us that bioreactor studies with product extraction could be successful and that we should move forward with Objective 3. This is the first time that acid whey was used to produce n-caproic acid (to our knowledge). Objective 3. Operate a long-term bioreactor study with product extraction and separation to produce n-caproic acid oil from the most promising acid whey and/or process waste stream. Objective 1 showed us that is did not matter which acid whey we would use and we have been feeding different acid whey batches to the bioreactors. Objective 2 showed us that acid whey could be converted into caproic acid within one anaerobic microbiome system. Therefore, we started with a single bioreactor of about 1 L and fed acid whey continuously. Indeed, we found some caproic acid, but the selectivities were low due the production of other carboxylic acids that are formed by a competing microbial pathway in the mixed community. Between the writing of the proposal and the start of the work we published a study (not funded through this grant) in which we found that we could produce n-caproic acid via lactic acid as the main electron donor for the microbiome. This opened the door to a two-stage bioreactor system for which lactose and fructose is first converted into lactic acid, and then the lactic acid is converted into n-caproic acid in a second stage. The environmental conditions in both stages are different in which we were able to control the microbial constraints in such a way that we eventually only produce caproic acid. This acid is being extracted from the second-stage bioreactor while it is being produced. This is new knowledge, since we now know that the conversion is possible, but we also now how to control the system in a manner not to activate the competing microbial pathways. Objective 4. Inform NYS Greek yogurt plant operators and owners about our technology (if promising in the laboratory). Since, we only recently have become successful and not have calculated the selectivities and efficiencies at steady-state conditions, we have not yet contacted the industry. Specific accomplishments: Acid whey fed at an organic loading rate of 56.7 g COD/L/d resulted in a net production of 34.9 g COD/L/d lactate in a first-stage bioreactor when it was operated at pH 5 and 50°C for long operating periods (months). When the second-stage bioreactor was fed with the effluent of the first-stage bioreactor at an organic loading rate of 7.1 g COD/L/d, a high production rate (4.85 g COD/L/day) of medium chain carboxylates (caproic acid and caprylic acid) was observed. The reactor was operated at pH 5.0, a temperature of 30°C, and with membrane-based liquid-liquid extraction (pertraction). This production rate shows the excellent potential of the conversion of acid whey to caproic acid oil.
Publications
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