Performing Department
(N/A)
Non Technical Summary
With growing populations around the world, our global food systems must grow to support a projected 9.7 billion people by 2050, increasing current food production by 70%. As if this problem wasn't hard enough, growers must achieve this feat using practices that are productive in the short-term, providing healthy and nutritious food, and sustainable in the long-term, reducing pollution and waste into the environment. One practice that has helped growers increase crop yields is fertilizer. In 2019, global fertilizer use was estimated at 215 million tons and is expected to grow by 2.5 million tons per year to accommodate increasing food production demands. One segment of this market is controlled-release fertilizers (CRF's), which combat some of the environmental challenges that traditional fertilizers face, like eutrophication and greenhouse gas emissions. But there are several barriers preventing the widespread adoption of CRF's: high cost of materials, complex manufacturing processes, lack of standardization, lack of information for growers, and emerging concerns and regulations regarding microplastic pollution resulting from the various polymer materials used as coatings and binders.There is an opportunity to develop a low-cost, biodegradable controlled release fertilizer platform that is easily manufacturable using high-throughput continuous processing equipment, helping the agriculture industry meet its production goals and sustainability goals. Our goals for this Phase II project are to: develop formulations of biodegradable lignin-polymers for controlled release fertilizer applications, demonstrate continuous production of these materials, evaluate nutrient release efficiency & performance in laboratory and greenhouse trials, and develop a comprehensive IP & commercialization strategy through the TABA program. At the end of this project, we aim to have at least 1 formulation of lignin polymers with Nitrogen, Phosphorus, or Potassium content that show tunable release rates between 2 and 6 months, demonstrating above- and below-ground plant growth, plant quality, and soil quality equivalent to or better than commercially available CRF's on the market today.
Animal Health Component
60%
Research Effort Categories
Basic
(N/A)
Applied
60%
Developmental
40%
Goals / Objectives
Our team at mobius has developed a proprietary technology to incorporate technical lignin as a primary feedstock for low-cost, biodegradable polymers. The primary byproduct of the paper & biofuel industry, lignin is generated at a rate of 200 million tons per year and is a low-cost feedstock, estimated at $0.05/lb. Our technology can tune the mechanical & end-of-life properties by altering the formulation. We can also incorporate organic and inorganic nutrients, undergo continuous production via twin-screw extrusion (standard production method for thermoplastics) for customizable, low-cost CRFs, all without the need for any specialized processing equipment used to manufacture conventional CRF's.Our goals for this Phase II project are to: develop formulations of lignin-polymers for controlled-release fertilizer applications, demonstrate continuous production of these materials, and evaluate nutrient release efficiency & performance through laboratory validation experiments and greenhouse trials. We propose a 4-stage work plan to achieve these goals (see below), which includes Formulation Development, Laboratory Validation Testing, and Greenhouse and Field Trials (Stages 1-3). These Aims will complement our proposed TABA Commercialization Activities we will be working on in parallel (Stage 4). At the end of this project, we aim to have 1+ lignin-polymer formulations with added nitrogen, phosphorus, or potassium nutrients with controllable release profiles and rates between 2 and 6 months. This time window correlates to commercially available CRFs presently on the market. As stretch goals, we are proposing to blend lignin-based formulations with multiple nutrients targeting release rates for specific commercial crops, and we would also like to explore the application of aqueous or green-solvent based lignin-polymer coatings. This work plan will iterate between stages and incorporate continuous input from customers, partners, and other stakeholders in the fertilizer industry.Our Phase II work will focus on the following hypotheses:Hypothesis 1: Lignin-based biodegradable polymer formulations can be tuned to control the release rates of nitrogen, phosphorus, potassium, and other nutrient mineral salts or small organic molecules using a combination of osmosis and hydrolysis of polyester copolymers driven by microbial enzymes at ambient temperatures.Hypothesis 2: Lignin-based biodegradable polymer formulations can be tuned to have non-linear release rates of plant nutrient ions and small molecules, matching the nutrient needs of targeted plants.Hypothesis 3: Lignin-based polymers, when used as a biodegradable binder and/or coating for controlled-release fertilizer applications, can achieve equivalent or better growth performance as current market CRFs.Hypothesis 4: Biodegradable polymer binders and/or coatings for fertilizers can release >95% of their nutrients, compared to the average 80% released by current market CRFs.Hypothesis 5: Lignin-based biodegradable polymers, with or without fertilizer, will improve soil health as measured by an increase in humic matter and beneficial microbial populations.To evaluate these hypotheses, we propose the following Specific Aims for this projectSpecific Aim 1: Demonstrate that formulation changes in biodegradable lignin-polymer materials facilitate release of small organic molecules and ions out of or through the polymer matrix with controlled release of 80% of said molecules and ions between 2 and 6 months.Specific Aim 2: Identify (2) formulations for each nutrient that meet baseline specifications under laboratory conditions.Specific Aim 3: Conduct greenhouse trials with commercially relevant plants to evaluate usability and effects of lignin-polymer fertilizers on plant & soil healthSpecific Aim 4: Identify IP & commercialization strategies (TABA)Stretch Aim 1: Identify blends of N, P, and K formulations for marketable productsStretch Aim 2: Investigate processes to create water- or solvent-based polymer coatings
Project Methods
Our goals for this Phase II project are to: develop lignin-polymer formulations for controlled release fertilizer applications, demonstrate continuous production of these materials, evaluate nutrient release efficiency & performance in laboratory and greenhouse trials, and develop a comprehensive IP & commercialization strategy through the TABA program. To achieve these goals, we are proposing a 4-stage work plan, which includes Formulation Development, Laboratory Validation Testing, and Greenhouse Trials (States 1-3). These Aims will complement the Commercialization Activities we will be working on in parallel (Stage 4).By the end of this project, we aim to develop at least (1) lignin-polymer formulations with Nitrogen, Phosphorus, or Potassium content with 2-3 month, 3-4 month, and 5-6 month nutrient release rates, corresponding to commercially available CRFs. As a stretch goal, we will propose blends of these lignin-based polymers with N, P, and K nutrients for targeted commercial crops.The following section describes our Phase II work plan, which is divided into 10 Tasks and 2 Stretch Tasks to support our aims and hypotheses mentioned above. Our product development strategy uses set-based concurrent engineering, a framework which creates a large number of potential "solutions" to be qualified against stringent specifications. We believe this strategy is highly applicable to polymer engineering as multiple polymer formulations can meet product specifications. The milestones listed in the figure below will serve as critical review points to identify viable candidates with partners and stakeholders. This work plan is designed to be iterative with feedback from customers, partners, and stakeholders. The methods for the project include:Material Formulation and Characterization - The mobius team will use a design of experiments (DOE) methodology to evaluate the impacts of various polymer formulation variables for controlled release fertilizer applications, focusing on identifying controls for a targeted 80% release of key nutrients (N,P,K) between 2 and 6 months (see Task 3). This variables we will investigate include (1) varying lignin and polymer types, blend ratios, and catalyst loadings based on our previous work in this space, (2) selection and pre-processing of nutrient salts and organics via drying, milling, and sieving to control domain size, (3) incorporation of compounds to control water resistance and permeability including natural fibers (wicking water and dissolved compounds across polymer bulk), lipids (increasing polymer hydrophobicity), and platelet nanoclays such as bentonite, montmorillonite, and talc (increasing mean free path for water or dissolved compounds across the polymer bulk), and (4) the evaluation of all material compatibility during batch and continuous compounding. We will examine the water vapor transmission rate of thin films pressed from various formulations (ASTM F1249) and water and ion transport across various formulations at different temperatures, as well as observe polymer morphology and compounded nutrient domain sizes using electron microscopy (UTIA). Formulations will be compounded using batch (torque rheometer) and continuous (twin-screw) methods. We will focus on formulations with high lignin content (>30 wt%), with bio-based and/or biodegradable copolymers (PBAT, PBS, PHA, PCL), and with known salt or organic nitrogen sources (urea, ammonium sulfate, ammonium chloride, etc.), phosphorus sources (phosphate salts), and potassium sources (potassium salts). This task may be repeated twice across the duration of the work plan to allow for feedforward adjustment.Small Scale Production of Materials & Prototypes - The mobius team will take a subset of formulations from Task 1's results and produce large quantities (50+ lbs.) of these materials on our 27 mm twin-screw extruder. We will use these materials in laboratory validation and plant growth trials (Task 3-8). This Task will include process optimization for continuous production by tuning extruder zone temperature, feed rates and zones, screw and barrel design, screw speed, and material offtake.Nutrient Release Tests (Lysimeters) - We will measure the nitrogen, phosphorus, and potassium release rates of materials from Task 1 & 2 in laboratory conditions using lysimeters. Lysimeters are columns filled with actual soil or an artificial soil media and a single fertilizer material. Time points are collected once per week, and temperatures can be controlled by housing the lysimeters in an isothermal oven or environmental chamber. Using this setup, we will calculate the cumulative release rate of nutrients in both microbially active soil and abiotic mock soil under consistent water flow, at least two temperature points (above and below 75-80F which is the "activation" temperature of most current market CRFs) and model how the materials will perform in real world conditions. We will also investigate how the materials compare to current market CRF products, and also measure additional features including water holding capacity, water contact angle, and material swelling. "Spent" samples of CRFs will be saved for Tasks 4 and 7.Humic Matter & Soil Analysis - mobius will work with Dr. Jennifer DeBruyn at the University of Tennessee Institute of Agriculture (UTIA) to measure the humic matter content released from fertilizer materials in the lysimeter experiments (Task 3). We will also conduct microbial and fungal population analyses (16S and ITS Sequencing) and soil quality analyses in an attempt to understand overall soil health benefits, if any, and to identify potential biotic mechanisms contributing to nutrient release and potential vectors for improved nutrient turnover or plant uptake. Insight on these mechanisms may inform on formulation for increased nutritional value and maximize plant & soil health.Material End-of-Life Analysis - mobius will send samples of the formulations identified in Task 1 to the Bioproducts Institute for End-of-Life analysis, which includes material disintegration and industrial compostability, following established ASTM methods and standards.Greenhouse & Field Trials -This task evaluates the performance of our materials in real-world, greenhouse & nursery conditions. We will conduct (2) 10-week plant growth trials over the course of this project (with room in between for formulation & production modifications if needed). We will conduct these trials with our greenhouse and field partners at Agricenter International and will include up to 4 commercially-relevant plant varieties, with at least one turf grass, one container-grown tree, and the others selected from flower or vegetable cultivars, with 8-10 replicates per formulation for statistically relevant results. These trials will compare against current market CRFs.Plant & Soil Health Analyses -We will evaluate plant & soil health at the end of each 10-week trial and conduct soil & microbial analysis to explore effects of fertilizers on microbial activity. We will work with our greenhouse partners at Agricenter International to evaluate plant health from a retail perspective and work with our partners at UTIA to conduct comprehensive analyses of the soil & microbial communities (similar to Task 4). We will also conduct these analyses for the commercial fertilizer controls.Usability Tests & Grower Scores -We will work with greenhouse partners and industry stakeholders to assess the performance of the various formulations, throughout and after the completion of Task 7. This assessment will compare performance of each fertilizer (lignin-based and controls) with a composite score, categories include manufacturability, nutrient release, biodegradability, plant health, soil health, and user score. The user score is a subjective evaluation based on the feedback from experts and industry partners.