DOI
https://doi.org/10.1021/acs.jchemed.9b00754

Summary
The paper presents issues about plastic pollution. Plastics that are oil-derived take thousands of years to biodegrade and therefore there is significant demand to produce green and sustainable alternatives. Such plastic substitution would contribute toward addressing the United Nations Sustainable Development Goals (UN SDGs), which seek to address global challenges such as those relating to poverty, inequity, climate and environmental degradation, prosperity, peace and justice. Bioplastics are plastics that are derived from renewable biomass sources and offer an alternative to their oil-derived counterparts. The paper also presents some examples in the literature of bioplastics being incorporated into curricula: (a) an activity to valorize waste lobster shells (in the form of chitin) to produce plastic objects, (b) an activity to insolubilize casein, one of two proteins (together with whey) from milk, by an acid such as vinegar to form a bioplastic.
Furthermore, the paper describes the development of a demonstration to introduce students to waste valorization in order to form bioplastics. Waste valorization is the process of reusing, recycling, or composting, from waste, useful products or sources of energy. In this demonstration, waste valorization is introduced by converting sour milk into a bioplastic via the addition of lemon juice upon heating. Utilizing lemon juice to perform the acidification offers a greener procedure than the traditional formaldehyde (used commercially to make galalith) and enhances the transferability in remote locations such as the Amazon Rainforest in comparison to vinegar. While this demonstration to valorize sour milk using green and available reagents and processes allows students to consider the life cycle of materials with specific emphasis on waste valorization, taking a whole system thinking approach to designing this resource uncovered potential issues and additional learning outcomes for students.
However, it is noteworthy that this process is also used to make cheese, so there is an ethical discussion to be undertaken as to whether such a process that is utilized to feed citizens should be used to make a decorative bioplastic. As such, instructors may consider carefully whether to utilize this resource, and, if so, to use this as an opportunity to teach the importance of ethics in science.

Relevance for Complex Systems Knowledge
The paper deals with interdisciplinarity, systems thinking, and sustainable development.
Authors point out that systems thinking uses cognitive frameworks, strategies, and tools to enable visualization of interconnections and relationships among components of systems together with an examination of the dynamic nature of systems and how systems-level phenomena emerge from interactions among the system parts. They argue that within education, this approach can help students to address complex, interdisciplinary, real-world problems that are aligned with the UN SDGs. Indeed, they report examples of the use of systems thinking to inform curricular change and resource development within green chemistry and sustainability.
Authors also claim that students can establish connections to relevant United Nations Sustainable Development Goals (UN SDGs) by adopting a systems thinking approach.

Point of Strength
The strength of the publication is the presentation of various version of an experiment that differ in respect to their contribution toward addressing systems thinking and sustainability.