Source: AUBURN UNIVERSITY submitted to NRP
CIRCULAR AQUACULTURE THROUGH A NEXT-GENERATION WASTE-TO-FEED BIOTECHNOLOGY
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
Reporting Frequency
Annual
Accession No.
1030611
Grant No.
2023-67021-39643
Cumulative Award Amt.
$650,000.00
Proposal No.
2022-10751
Multistate No.
(N/A)
Project Start Date
Jun 1, 2023
Project End Date
May 31, 2027
Grant Year
2023
Program Code
[A1531]- Biorefining and Biomanufacturing
Recipient Organization
AUBURN UNIVERSITY
108 M. WHITE SMITH HALL
AUBURN,AL 36849
Performing Department
Chemical Engineering
Non Technical Summary
In response to the fast-growing global population and increasing demand for animal protein, aquaculture is the fastest-growing animal food production sector worldwide. With growing competition for natural resources (land, water, etc.) among all production sectors, the intensification of aquaculture systems has emerged as a promising pathway for increasing aquaculture production. Accompanying the aquaculture intensification is the increased demand for feed and increased waste production. On the one hand, aquafeed is recognized as the critical factor limiting the aquaculture industry's growth. On the other hand, aquatic waste is often discharged into the environment, causing eutrophication and threatening the sustainability of local ecosystems. Therefore, sustained intensification of aquaculture production must be coupled with a sufficient supply of sustainable nutrients (feed) and efficient waste management.This project aims to develop and validate a novel, sustainable and profitable waste-to-feed (W2F) biotechnology, which solves the two problems mentioned above (i.e., limited aquafeed and increasing waste) with a single solution. The proposed W2F biotechnology integrates the commercially proven anaerobic digestion (AD) with a recently patented circulating coculture biofilm photobioreactor (CCBP) to convert aquaculture waste into single cell protein (SCP) as aquafeed supplements while producing treated clean water and fertilizer. The waste-derived SCP's efficacy as a nutrient source will be evaluated on Pacific white shrimp. The treated clean water will be tested to satisfy the EPA standards on total nitrogen (TN) and total phosphorus (TP) concentrations.
Animal Health Component
0%
Research Effort Categories
Basic
100%
Applied
0%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
40340992020100%
Goals / Objectives
Through the development and validation of a novel, sustainable and profitable waste-to-feed (W2F) biotechnology, we aim to help develop a circular aquaculture industry that not only helps feed the increasing global population but also significantly improves the industry's sustainability. The proposed W2F biotechnology integrates the commercially proven anaerobic digestion (AD) with a recently patented circulating coculture biofilm photobioreactor (CCBP) to convert aquaculture waste into single cell protein (SCP) as aquafeed supplements, treated clean water, and fertilizer. To develop and validate this W2F technology, we propose the following five specific objectives: (1) AD of fish sludge and food waste to produce biogas and nutrient-rich AD effluent; (2) develop a bench prototypeof the patented CCBP that converts biogas and AD effluent into SCP; (3) demonstration of continuous and stable SCP production using CCBP; (4) assessment of the efficacy of SCP as a nutrient source for shrimp; (5) assessing the technical and economic feasibility and sustainability of the proposed W2F biotechnology.
Project Methods
This trans-disciplinaryproject requires a broad range of scientific research activities that coverdifferent fields. As a result, we describe the involvedmethods corresponding to each objective.Objective 1: Anaerobic digestion of fish sludge and food waste to produce biogas and nutrient-rich AD effluentThe elemental analysis (C, H, N, and C/N ratio) and PSC of the waste samples will be performed at the AU Center for Bioenergy and Bioproducts following established protocols. For both analyses, 10 - 12 samples will be analyzed to determine the mean and standard deviations of all metrics for FS and FW samples. Mixtures of different FS/FW ratios will be prepared to obtain three levels of C/N ratio (15, 20, 25) and three levels of PCS (8%, 10%, 12%). Fishery wastewater will be used for feed mixtures dilution to control the C/N ratio and PSC independently. A full factorial design of FS/FW ratio and PSC results in 9 conditions to be examined. These comparative experiments will be conducted in one-gallon glass jars (covered with aluminum foil to block lights) with triplicates. AD process will be initiated by adding the activated sludge provided by CWW in Georgia, which has a commercial mesophilic AD installed. Biogas production volume will be measured by gas syringe (adjusted by pressure) till jar pressure lowers to 1 atmospheric pressure. The experiment will last up to 4 weeks or until vessel pressure no longer changes (i.e., no biogas generated from any jar). The AD performance metrics to be used are listed in Table 2 (of the submitted proposal). The primary metrics are biogas yield and productivity.The AD system will be monitored and recorded every three to five days based on the results obtained in Task 1.1, using the same set of metrics as listed in Table 2 (of the submitted proposal). All performance metrics will be determined batch-wise (cumulative for yield and average for the rest) for 3-4 batches to determine the metrics' mean and standard deviation. The robustness of the system will be evaluated in terms of the variability (e.g., minimum, maximum, standard deviation) of the performance metrics and the number of failures during the operation, if any.Objective 2. Construction of a scale-up CCBP with smart remote monitoringWe have developed a proof-of-concept 68 L lab-scale prototype of CCBP, and successfully validated its performance using artificial light and synthetic biogas. The development of the benchtop CCBP will follow the established process and methods that we have developed.In prior research, we have pioneered the applications of IoT devices for process monitoring, and developed protocols, hardware, and software for data acquisition, transmission, and storage systems for various IoT sensors.In this objective, following the established protocols we have published, we will deploy additional IoT devices and develop spectrum-based soft sensors to achieve real-time sensing/monitoring of the CCBP.Objective 3. Stable single-cell protein production using CCBPThe bentch-top CCBP will be activated following our proof-of-concept CCBP startup protocol. Once the CCBP operation reaches a stable condition, its performance will be assessed quantitatively. Gas and liquid samples will be taken twice daily (8 am and 8 pm) to determine the effect of diurnal changes, as there will not be photosynthesis during the dark period. Through gas phase composition and liquid phase (inorganic and organic N, P) measurements, we will quantify the baseline CCBP performance using metrics defined in Table 4 (of the submitted proposal). Following our established protocol, the harvested M-M coculture biomass will be subject to composition analysis to determine the protein, carbohydrate, lipid, and ash content.Objective4Assess the efficacy of the produced SCP as a nutrient source for shrimp.To assess the nutrient profiles and the variability of the CCBP-produced SCP, starting in year 2, coculture biomass samples will be collected intermittently (4-10 per year) and pooled together as needed to obtain quantities suitable for biochemical analysis. The collected samples will be dried and then analyzed for proximate composition as well as amino acid and fatty acid profiles, as well as heavy metal contents. The analysis will be conducted at the University of Missouri Agricultural Experiment Station Chemical Laboratories (Columbia, MO, USA) following standard practices. It will include analysis for proximate composition (protein, lipid, fat, fiber, and ash) for all samples and then for representative samples, amino acid, and fatty acid profiles, as well as pepsin digestibility.To assess the digestibility of the SCP, the test diets will be marked with 1% chromic oxide with the 70:30 replacement strategy following the established protocol. Dry matter, crude protein, and total energy will be determined for the fecal, diet, and ingredient samples according to established procedures.72 Finally, apparent digestibility coefficients (ADC) of the dry matter, protein, amino acids, and energy for each diet will be calculated.To evaluate nutrient availability, we will conduct a series of growth trials. The growth trials will be conducted at the E. W. Shell Fisheries Center following established protocols in the Davis lab73 and run under low salinity conditions (4-8 ppt). At the concluding growth trial, growth, survival, feed conversion, and nutrient retention will be determined.Objective 5: Comprehensive and integrated techno-economic analysis - life cycle assessmentThe proposed W2F technology will be evaluated for its technological and economic feasibility and sustainability through an integrated TEA-LCA. In this project, the following techno-sustainability metrics will be used to evaluate the proposed technology:Technical performance: (1) biomass surface area productivity; (2) biomass footprint area productivity; (3) energy consumption per unit biomass production; (4) nutrient recovery rate.Economic sustainability: (1) annualized capital and operating costs, investment, tax, revenue, and profit; (2) net present value (NPV); (3) minimum aquafeed selling price.Environmental sustainability: (1) net energy ratio (NER); (2) global warming potential (GWP); (3) water consumption; (4) waste and pollution generationSocial sustainability: (1) impact on local community FS management; (2) impact on local community water supply; (3) impact on local/regional economy

Progress 06/01/23 to 05/31/24

Outputs
Target Audience:The target audience includes researchers in academia interested in sustainable aquaculture and sustainable agriculture in general, agriculture waste management, and animal feed production. It also includes people in industry and agriculture who want to promote circular aquaculture/agriculture through the biological conversion of wastes into feeds. Finally, it includespolicymakers and funding agencies that highlyvalue circular bioeconomy and environmental sustainabilityand the general public who appreciateenvironmental sustainability. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project has provided training and professional development for two PhD students and two undergraduate researchers. The PhD students learned how to design experiments, develop experimental protocols to measure the variables relevant to the research goal, troubleshoot, identify the root cause for problems encountered, and analyze data through kinetic modeling. The undergraduate students learned basic cell cultivation techniques and how to search relevant literature. The PhD students presented their research findings at international technical conferences (AIChE and SBFC), as well as Auburn University Graduate Engineering Research Showcase, an annual symposium where graduate students share their research findings and compete for research awards. How have the results been disseminated to communities of interest?We have published one book chapter and one peer-reviewed journal article, with an additional one under review. We have presented the relevant research results at multiple conferences. In addition, the PD students have also disseminated the relevant results through internal symposiums and their teaching activities. What do you plan to do during the next reporting period to accomplish the goals?We will continue to execute the research plan presented in the proposal and disseminate our findings at external and internal conferences.

Impacts
What was accomplished under these goals? Further development of aquaculture intensification is limited by the supply of aquafeed and large amounts of waste production. Currently, aquaculture waste streams are often discharged into the environment, causing eutrophication of surrounding areas and threatening the sustainability of local ecosystems. To address these challenges, we propose to convert aquaculture waste into single-cell protein (SCP) as aquafeed supplements via a two-step process: 1) utilizing commercially proven anaerobic digestion (AD) to produce biogas from fish sludge (FS); 2) cultivating microbial biomass as feedstock for SCP production using a novel biofilm photobioreactor. For the first step, we expect the co-digestion of fish sludge (FS, rich in nitrogen) and food waste (FW, rich in carbon) to benefit biogas production and nutrient conversion. During the past year, using FS collected from Auburn University Fishery Center and FW collected from Auburn University Dinning, we performed comprehensive experimental studies to determine the optimal FS/FW feed ratio and solid content to optimize AD performance. Our experiments showed that adding FW enabledadditional biogas production that couldn't be fully explained by the added FW, confirming that adding FW can improve organic substrate breakdown and biogas production. In addition, there exists an optimal FS/FW ratio, as too much FW could result in a drastic pH drop and inhibit biogas production. These findings were presented at two leading technical conferences: the AIChE annual meeting and the Symposium on Biomaterials, Fuels, and Chemicals. For the second step, we have made major modifications to a lab prototype of the patented coculture circulating biofilm photobioreactor (CCBP), which is the key enabler for the biological conversion of biogas into aquafeed. We implemented a new driving system that rotates the substratum where microalgae-methanotroph coculture biofilm grows, added IoT sensors to monitor gas concentrations in the photobioreactor, and added an IoT infrared camera, which allows remote monitoring of the reactor.

Publications

  • Type: Book Chapters Status: Published Year Published: 2023 Citation: Wang J. & He Q.P., Microalgae-methanotroph cocultures for carbon & nutrient recovery from wastewater, in Lens P. and Khandelwal A. (Ed.), Algal systems for resource recovery from waste and wastewater, (pp 103-125), IWA Publishing. https://doi.org/10.2166/9781789063547
  • Type: Journal Articles Status: Published Year Published: 2024 Citation: Badr K., He Q.P. & Wang J., Probing interspecies metabolic interactions within a synthetic binary microbiome using genome-scale modeling. Microbiome Research Reports, 3(3): 31, invited paper. http://dx.doi.org/10.20517/mrr.2023.70
  • Type: Journal Articles Status: Submitted Year Published: 2024 Citation: Murphy L., He Q.P. and Wang J., Identifying synergistic methanotroph-photoautotroph cocultures for wastewater remediation through an expeditious in-house screening system, Journal of Environmental Management, submitted.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Wang J. and He Q.P. (2024), Biogas conversion using methanotroph-photoautotroph cocultures: recent developments in coculture characterization, modeling and bioreactor design, Gas Fermentation Conference, Feb. 21-25, Heron Island, Australia (invited).
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Khorasani R., Wang J. & He Q.P. (2023), A Systematic Study of Co-Digestion of Fishery Sludge and Food Waste for Biogas Production, AIChE annual meeting, Nov. 5-10, Orlando, FL.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Khorasani R., Wang J. & He Q.P. (2024), Quantification and optimization of biogas production from mixed fish sludge and food waste, 46th Symposium on Biomaterials, Fuels and Chemicals, Apr. 28  May 1, Alexandria, VA
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Wang J., He Q.P. & Khorasani R., Enabling circular aquaculture with a biofilm-based waste-to-feed biotechnology, AIChE annual meeting, Oct. 27-31, San Diego, CA