Grantee Research Project Results
Final Report: Beetle larvae as biodegraders of styrofoam and organic waste
EPA Grant Number: SU839283Title: Beetle larvae as biodegraders of styrofoam and organic waste
Investigators: Nansen, Christian , Fowles, Trevor , Cheng, Brian , Favilla, Amanda
Institution: University of California - Davis
EPA Project Officer: Page, Angela
Phase: I
Project Period: September 1, 2017 through September 30, 2018
Project Amount: $14,998
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2017) RFA Text | Recipients Lists
Research Category: P3 Awards , P3 Challenge Area - Chemical Safety , Sustainable and Healthy Communities
Objective:
Styrofoam (polystyrene) is one of the leading contributors to landfill waste. Darkling beetle larvae (Tenebrio molitor) have the ability to consume styrofoam due to identified gut-symbionts. This project sought to implement and optimize darkling beetle biodegradation to address challenges presented from disposing styrofoam. After providing biodegradation services, the beetles may be pelletized for animal feed, and their excrements can may be used as high-value amendment to compost mixtures. While styrofoam by itself is a poor nutrient source for the beetle larvae, this waste material can be mixed with organic waste materials, such as, pulp from wine and tomato industries, to optimize beetle development. In this project, we sought to optimize each of these aspects in implementing beetles for styrofoam biodegradation. We sought to 1) increase biodegradation service via artificial selection (i.e. breeding) to develop high-performance beetle strains; 2) optimize rearing parameters, including development of optimal mixtures of styrofoam and organic waste. The overall outcome of Phase I was to have specialized strains and rearing procedures for a pilot system using insects to break down large quantities of styrofoam. Which would be developed further under Phase II.
Summary/Accomplishments (Outputs/Outcomes):
Styrofoam degradation is enhanced with the addition of other diets. That is, both the consumption of styrofoam and consumption of additive is higher in mixed diets. In this case, tomato and wine pomace from nearby agricultural producers. However, styrofoam alone is not sufficient for survivability, weight gain, and biodegradation. Further, mealworms display marked plasticity in biodegradation capabilities, suggesting high breeding potential. However, the duration for development to adults is comparatively high on non-conventual diets, thereby leading to the development of more than two full generations difficult within the time frame. Though the evidence suggests this can still be done. Finally, experiments using the biodegraded mealworm frass is not suitable for a soil amendment in concentrations higher than 25%. Though germination of seeds was lower in all treatments other than the control.
Conclusions:
The results suggest that styrofoam added to the diet mix of these insects increases weight gain and the total amount consumed overall. This results in more styrofoam being bioconverted into feces. However, the byproduct of the bioconversion does not seem to confer added benefits to plants when used as a soil amendment, rather, it appears to inhibit germination of some plant seeds. In addition, over the course of this project, undergradates have notices some of the feces still contain styrofoam in very small particulate. Which may be an irritant for workers. Furthermore, it akes much longer to develop styrofoam consuming beetles into adults. This leads us to conclude that in order to make a breeding program to take advantage of the phenomena of styrofoam reduction in these beetles, one would require a significant amount of time and resources compared to other insect species. For these reasons, we are of the opinion that while styrofoam biodegredation is an attractive research persuit, further work should be at investigating the microbial components for use of bioreactor biodegredation instead of biodegredation in sutu.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
Cradle to cradle, life cycle analysis, recycling technologies, closed loop recycling, renewable feedstocks, model for sustainability, feed stocks, recycling, waste to value, agricultural byproducts, animal feedRelevant Websites:
UC Davis Graduate Student Scores EPA Grant Involving Mealworms and Styrofoam Exit
Why These Mealworms Don't Miss a Meal Exit
EPA awards grant to UCD for innovative technology project Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.