IMPROVING SUSTAINABILITY AND EFFICIENCY IN HORTICULTURE WITH DEGRADABLE LIGNIN-POLYMER CONTAINERS

There is an opportunity for a new bio-based material platform to produce a family of low-cost and biodegradable containers with a range of mechanical performance, sustainability, and opportunities to improve plant health properties. The existing work to identify new bioplastic formulations for containers in horticulture has not found a material that can match the price, availability, and performance of petroleum-based plastics. The work to date has focused on using PLA, PHA, or starch as the primary polymer and adding fillers, colorants, and other additives to improve performance, cost, and aesthetics. The high price, low availability, and mechanical property limitations restrict their adoption. Even with increases in availability and decreases in price, the poor degradability of materials like PLA are difficult to overcome. In contrast, our technology uses lignin, a byproduct from the paper and biofuel industry. Lignin is generated at a rate of over 200 million tons per year, is low cost, and is a widely available biorenewable material feedstock. Lignin can provide a foundation for a new family of bio-based and biodegradable container materials.Our goals for Phase II are to continue development of lignin-polymers for horticulture applications by: (1) identifying lignin-polymer formulations that meet the manufacturing & technical specifications of our customers; (2) demonstrate equivalent or improved plant & soil health compared to petroleum-based containers; (3) develop a comprehensive IP & commercialization strategy through the TABA program. Here we propose a 4-stage work plan to achieve these goals with iterative loops between Formulation Optimization, Manufacturability Trials, and Greenhouse Trials (Stages 1-3 below). These Aims will complement the commercialization activities occurring in parallel (Stage 4). Lastly, our stretch goal is to demonstrate the production of container prototypes with added nutrient content. This work plan is designed to be iterative with input from customers, partners, and other stakeholders in the horticulture industry.To study the effects of bioplastic containers on plant health, we will grow greenhouse and tree crops in various containers in a professional hoop house or greenhouse. In order to gather sufficient data, we will carry out these tests using 3-4 different plant varieties in a standard soil mix based on recommendations from our partners at Agricenter International. We will also leverage feedback from our partners at Summit Plastic and McConkey & Co., who manufacture thermoformed and injection molded pots, respectively. Ideally, we will choose at least one flower, one vegetable, and one tree - each with tolerance to changes in pH and are in high commercial demand for retailers and consumers. With the time permitted by the grant, we will be able to perform two production trials, which will allow us to test these plants multiple times throughout the year and/or select new plants for the trials. To characterize plant health, we will measure plant shoot size, root health (evidence or absence of root circling), plant and flower color, presence or absence of chlorosis/necrosis, water nutrient content, and the dry weight of roots and plant biomass.Our Phase II will focus on the following hypotheses:Hypothesis 1: Lignin-based polymers can match or exceed the mechanical, aesthetic, plant health, and sustainability characteristics of petroleum-based plasticsHypothesis 2: Lignin-based polymers can be optimized for injection molding and thermoforming processes to create containersHypothesis 3: Mechanical and end-of-life properties for containers can be optimized based on formulations for specific plant types & greenhouse needsHypothesis 4: Lignin-based polymers can provide nutrients as they degrade and improve plant and soil health, compared to traditional containersTo evaluate these hypotheses, we propose the following Specific Aims for this project:Specific Aim 1: Optimize 2+ polymers that demonstrate good mechanical & processing properties for injection molding and are degradable in industrial composting conditions.Specific Aim 2: Determine manufacturability of polymer formulations with external partners to create container prototypesSpecific Aim 3: Conduct greenhouse trials to evaluate product usability and effects of lignin-polymer containers on plant & soil healthSpecific Aim 4: Identify IP & commercialization strategies (TABA)Stretch Aim 1: Demonstrate container prototype of 1+ formulation with added nutrients