Integrated Human Practices
The Human Practices aspect of iGEM pushes teams to be adaptable. Talking to experts and stakeholders uncovered information that changed the foundation of our project while ultimately moving our project beyond the lab. Through conversations with growers and experts in agriculture, we began to understand the logistics of making a bed mulch film and just how essential they are to the industry. Every interview we participated in helped shape our project into Komaplastics. Human Practices allowed us to strive for a product that growers would be comfortable using and one that experts would be happy to support.
Before conducting our interviews, it was necessary to recognize the gaps in our knowledge about the issue of agricultural plastic waste and the work required in the wet-lab to produce a solution. Our first step was determining what farmers thought about current biodegradable bed-mulch plastics. This was our push to interview growers and experts who are in frequent communication with growers, to get a better understanding of the push backs against using biodegradable bed-mulch plastics in the field.
The timeline of human practices came together through each interview we did. The steps were:
- Understanding the need for a biodegradable plastic mulch.
- Understanding what standards/tests current agricultural films need to pass.
- The viability of implementing a biodegradable alternative.
- Learning about the barriers in farming practices.
- Addressing concerns about the science and technology behind our film.
Interviews with Stakeholders
We were fortunate enough to talk with Dave Peck who is a strawberry farmer with Manzanita Berry Farms. He was eager to adopt a biodegradable bed mulch film noting how it could be tilled into the ground negating the need to remove the film by hand, potentially saving hundreds of dollars per acre in labor costs. Mr. Peck is dissatisfied with current biodegradable films explaining how they degrade prematurely and are incompatible with fumigation protocols. No biodegradable bed mulch film has passed fumigant permeability protocols, making them useless for strawberry farming. A film used during fumigation must be virtually impermeable to fumigants to prevent contamination of immediate areas while maximizing fumigant efficacy. Mr. Peck was insistent that our film pass fumigation permeability protocols and suggested speaking with Dr. Husein Ajwa, a foremost figure in fumigation protocols.
Dr. Husein Ajwa is a professor emeritus at UC Davis, a leading researcher in fumigation of agricultural films, and the owner of Ajwa Analytical Lab LLC. Dr. Ajwa generously gave us a tour of his fumigation lab in Gilroy, CA where he demonstrated fumigation protocols every film must pass to be used in the field. We learned which films are used commonly, their properties, and grower opinions. Growers love working with Raven™ bed mulch, a Totally Impermeable Film (TIF), because of its elasticity. Dr. Ajwa generously provided us with samples of different films he had been testing in the lab, including the popular options growers use. He also gave us biodegradable films to show us how many of them do not stretch, leaving growers unsatisfied. Dr. Ajwa considers elasticity to be the most important quality in a film and encouraged us to emulate it because growers might not buy it otherwise. The films he provided helped guide us in what qualities growers desire in a plastic bed mulch. We also used these films in our crystallinity standard testing. This helped us build a crystallinity index we would compare to our cellulose and how much decrystallization we need to reach to make a successful bed mulch film.
In addition, we learned that our film would have to be impermeable to fumigants for at least one month and last approximately 6 months before it begins to biodegrade. Dr. Ajwa also provided insight into achieving biodegradability and fumigant impermeability while suggesting we look into co-polymers as possibly plasticizers for our cellulose.
We contacted Dr. Steven Fennimore, Husein Ajwa’s colleague, who does work in the Plant Sciences Department at UC Davis. They worked together on TIF films and fumigation practices. Dr. Fennimore introduced us to the UC Davis Cost and Return Studies which contains a compilation of the total cost of production for many crops across the state of California. These studies proved how a biodegradable plastic could save farmers money from the elimination of labor costs in removal of mulch which wouldn’t be necessary if using a truly biodegradable film. The UC Davis Cost and Return Studies also helped us envision a potential price for our mulch.
We spoke with Dr. Lisa DeVetter, a small fruit horticulturist at Washington State University, to learn more about contemporary biodegradable films and her work with strawberries. She is currently part of a multi-university research initiative evaluating the effects of biodegradable mulches over a 5 year period. Dr. DeVetter presented us with relevant policies involving biodegradable film production and put us in contact with polymer scientists who could speak on what makes a good, environmentally friendly plasticizer. She also made us aware of the American Society for Testing and Materials (ASTM) standards. These are standardized testing methods used to comparatively evaluate different materials and systems. She encouraged us to consider how we will address current barriers to biodegradable film production outlined in ASTM standards and the National Organic Program regulations. She spoke on the pros and cons of current biodegradable plastics and noted how many smaller scale farmers are interested in biodegradable bed mulches. She also put us in contact with Dr. Doug Hayes and Mark Bolda who would help us with learning more about co-polymers and biodegradable mulches.
We spoke with Dr. Joji Muramoto who is part of the UCSC community. He is very involved in soil fumigation practice development and a verified organic specialist. We contacted him to understand how we could create a biodegradable bed mulch film that accommodates organic farming. Currently no biodegradable films are approved for organic food production. He talked to our team about the increase in organic food production due to social influence which led to more lenient regulations regarding what can be labeled as “organic” by larger corporations. He described to us that only PE plastics are available for organic farming. These mulches can leave behind harmful microplastics. He encouraged us to continue development of a bio-based film that could potentially be used in organic agriculture. This interview helped focus our attention towards finding regulations that explain why biodegradable plastics are not used in organic farming.
We talked with Dr. Carol Shennan, who is also a part of the UCSC community, to further our knowledge about organic farming and the possible use of biodegradable bed mulch film. Dr. Shennan encouraged us to push for a conversation with the United States Department of Agriculture (USDA) about Organic Regulation 7 CFR 205.206 which explicitly states that biodegradable films produced from recombinant DNA technologies are prohibited from use in organic farming. This led us to email Devon Patillo from the National Organic Standards Board (NOSB) who told us how we can submit a comment about our issue to support using our biodegradable plastic in organic farming.
Mark Bolda is the Strawberry and Caneberry Farm Advisor in Santa Cruz, Monterey and San Benito Counties who was mentioned by Lisa DeVetter. Mr. Bolda is heading a multi-state project to convince growers to convert to biodegradable plastic mulches by 2030 by traveling to those growers to show the benefits of biodegradable mulches. We contacted Mr. Bolda in the hopes that he could give more insight into how growers feel about biodegradable plastics and understand if this product is something of interest to them. He relayed how farmers do want to switch to biodegradable plastic mulches. They are even willing to pay a little more money for them, but growers are still hesitant to take on biodegradable plastics because they want to know it won’t harm their plants, how these plastics breakdown, and what residues are left behind. He also mentioned how the main bed mulch recycling facility in Salinas, California is no longer operating. Many people in northern california would send their mulches here before its closure. Now most bed mulches are sent directly to the landfill making the implementation of biodegradable plastic mulch more important than ever.
Mr. Bolda told us that once we have a product ready, he is more than happy to help us test it in the field, suggest improvements, and connect us with interested farmers. This interview showed us the importance of understanding what our breakdown products are from our desired biodegradable mulch. We knew cellulose breaks down to glucose monomers but wanted to understand the breakdown of prospective plasticizers and carbohydrate binding modules (CBMs). Thus, the conversation with Mr. Bolda directed us towards Oded Shoseyov who has worked extensively with CBMs.
We contacted Dr. Oded Shoseyov, a professor at the Hebrew University of Jerusalem and expert in CBM incorporation into cellulose based films. He wrote the first publication we read about CBMs which provided a foundation for our research . Dr. Shoseyov explained to us that CBM3a is highly characterized and would be a good CBM to begin experimenting with incorporation into our film. He also encouraged us to remove the mRFP from our gene block because inclusion of a fluorescent protein may hinder the attachment of a CBM to cellulose. This would help us design the framework to improve on the existing Toulouse 2018 Sirius-CBM3a part in the iGEM registry by understanding the affinity of a CBM without inhibition of a large protein such as the mRFP. He advised us on how we could perform a different selection process that wouldn’t involve the fluorescent protein. Dr. Shoseyov also recommended and discouraged use of specific plasticizers. He pushed for using glycerol and citric acid as plasticizers and told us to move away from glutaraldehyde, which we were testing, because it is toxic.
We interviewed Dr. Doug Hayes, an expert in biopolymer film production, specifically incorporation of PHA’s (Polyhydroxyalkanoate). He is also involved in the 5 year multi-university initiative to test the effects of biodegradable films on soil along with Lisa DeVetter. We reached out to Dr. Hayes to gain a better understanding of plasticizer choice and the potential effects of biodegradation of our film on the soil. He suggested we use a vacuum oven to cure our potential plastic to better remove water. He also encouraged us to continue exploration of glycerol as a chemical plasticizer and suggested a few other options such as epoxidized vegetable oils. He was able to provide extensive advice about the use of PHA’s as we began to explore the potential for copolymer inclusion to our cellulose-based film. This interview reaffirmed much of our plasticizer testing protocols and encouraged us to search for new machinery, a vacuum oven.
Each interview we did guided our project to become something we are proud to put our name on. We took advice the experts in the agricultural field provided us in order to make a product they are excited to see be implemented into fields all around the world.