Progress 07/01/24 to 06/30/25

Outputs
Target Audience:1. We have communicated withMaine Potato Industry for potential usage of our developed lobster shell derived soil amendments. 2. We have communicated with Maine Lobster Industry such as Ready Seafood Inc. for sustainable lobster shell supply and identified chemical company that can be a potential collaborator in large-scale lobster shell meal production. 3. We have discussed the possibility of establishing a field trial in Canada with local potato growers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Two M.S. graduate students, Alex Pierce and Georgia Hynes, have been trained through this funding. Alex, recruited through the Food Science and Human Nutrition Program at UMaine, is focused on developing green processing methods for lobster shells using subcritical water technology, as well as conducting techno-economic analysis to assess the feasibility of the developed process. Georgia, recruited through the Plant and Soil Science Program at UMaine, is investigating the effectiveness of organic amendments in suppressing soilborne pathogens and influencing the dynamics of soil microbial communities. Both students have received training in fundamental and essential laboratory skills, including experimental design, proper use of laboratory equipment, data analysis, and poster/oral presentation techniques. To foster interdisciplinary learning, we hold bi-weekly meetings between the two research groups, allowing the students to share research progress and gain insights from each other's fields. This structure promotes cross-disciplinary communication and enhances their ability to convey research findings to diverse audiences. Additionally, we support student participation in academic conferences, such as the UMaine Student Symposium and the AIChE Annual Meeting, to further develop their presentation skills and expand their professional networks. How have the results been disseminated to communities of interest?Although it is still early to widely disseminate the full results, we have shared preliminary findings at the UMaine Student Symposium, Maine Potato Board meetings, and the Maine Lobster Institute meetings. These presentations have generated interest from stakeholders across the state of Maine, including the potato industry, agricultural advisors, and potato growers, and some from as far as Canada. Several growers have already expressed interest in applying our final products to their potato production systems to enhance soil health and improve crop yield. What do you plan to do during the next reporting period to accomplish the goals?First, we will continue the field and greenhouse trials and complete data collection to evaluate the efficacy of lobster shell-derived organic soil amendments in enhancing potato production and suppressing soilborne diseases. Second, we will investigate the mechanisms by which Bacillus velezensis degrades chitin from the lobster shell amendments and how this interaction enhances potato defense against fungal pathogens. Third, we will advance the techno-economic analysis to assess the economic feasibility of the developed process and determine the minimum selling price of the lobster shell-derived soil amendments.

Impacts
What was accomplished under these goals? Soilborne diseases pose a significant threat to agricultural productivity, and the widespread use of synthetic pesticides to manage them raises serious sustainability concerns. This project seeks to develop effective and economically viable organic alternatives by transforming abundant, underutilized lobster shells into cost-effective organic soil amendments. Progress Summary Objective 1. Create a suite of organic amendments with distinct particle sizes (through sequential milling) and compositions (through CO2assisted subcritical water fractionation). During this reporting period, we completed Objective 1. We first produced three particle sizes of lobster shell meal using (1) a single pass through a disc mill, (2) a double pass through the disc mill, and (3) a disc mill followed by ultra-centrifugal milling. The ground samples were then subjected to pretreatment in a Parr reactor using either pressurized hot water or mild alkaline solutions to remove protein, yielding a high mineral and chitin fraction (HMCF). This was followed by a second step using pressurized carbonic acid to remove calcium carbonate (CaCO?), producing a high chitin fraction (HCF). In the protein removal step, we evaluated various temperatures (140-200°C), treatment times (30 and 60 minutes), and reagents (water, NaHCO?, and Na?CO?). Pressurized hot water alone achieved a maximum protein removal efficiency of 51% at 200°C for 30 minutes. The incorporation of mild alkaline reagents improved efficiency significantly, with optimal results of 75% removal efficiency obtained using 1 M NaHCO? at 160°C for 30 minutes, comparable to conventional NaOH-based method. The resulting solid residue, referred to as the high mineral and chitin fraction (HMCF), is being used in soil amendment testing. For the demineralization step, HMCF samples were mixed with water and treated with CO? in the Parr reactor at varying pressures (0, 15, 30, and 45 bar) and durations (60, 120, and 240 minutes). The best CaCO? removal efficiency (74%) was achieved at 30 bar for 240 minutes. The resulting solid, known as the high chitin fraction (HCF), serves as another organic soil amendment for subsequent soil testing. Objective 2. Investigate the efficacy of amendments to suppress soilborne disease of solanaceous plants (potato and tomato) and enhance soil microbiomes. We initiated our field trial this summer using potato (cv. Kennebec) as the model crop. Two application rates of lobster shell-derived soil amendments (500 and 1000 lbs/acre) are being tested. Key evaluation metrics include tuber yield and grade, disease incidence and severity, and microbial community structure. Soil samples are being collected at pre-planting, emergence, and harvest stages, along with plant emergence counts. In parallel, a greenhouse experiment is underway at the Roger Clapp Greenhouse to investigate plant defense responses triggered by chitin and chitinolytic organisms. Data collection is currently in progress. Objective 3. Conduct techno-economic analysis (TEA) to evaluate the economic feasibility of the shell-derived amendment production. We have initiated the process modeling component using SuperPro Designer. A detailed process flow diagram has been completed, and we are currently working on material and energy balances, operating cost and total capital investment calculations. These calculations are being sourced from literature values and vendor quotes. Additionally, in the first year of this project, we have generated strong interest from both potato growers and the seafood processing industry in Maine, indicating promising potential for industry engagement and application.

Publications