Soybean By-Products Bioplastic (Polylactic Acid)-Based Plant Containers: Sustainable Development and Performance Study

Abstract

In most cases, plant containers used in the horticulture industry are not reusable, have many negative impacts on the environment, and take a long time to degrade. To reduce the use of non-biodegradable plant containers, many bio-degradable plant containers have been developed for the horticulture industry. However, the full potential of the sustainability of plant containers is yet to be completely explored. Therefore, two novel biodegradable plant containers are developed in this research to effectively contribute to sustainability’s environmental, social, and economic dimensions. The two biocomposite formulations are developed by mixing soy hull and soy protein isolate (SPI) with polylactic acid (PLA) matrix for plant containers. In the first formulation, the proportion of PLA and soy hulls are 70 wt% and 30 wt%, respectively; in the second formulation, 65 wt% PLA is blended with 30 wt% soy hulls and 5 wt% SPI. The injection molding process is used to manufacture the plant containers from the two formulations. In a field trial, four plant species are grown in the novel plant containers along with polyethylene and commercial PLA/DDGS (dried distiller’s grains with solubles and PLA-based container) containers to investigate biodegradability and plant growth. The results show that the containers from the new formulations outperform existing biodegradable PLA/DDGS containers in terms of certain plant growth and biodegradability.