Levi’s, Method and Berkeley students on a safer chemical crusade

The Right Chemistry

Levi’s, Method and Berkeley students on a safer chemical crusade

green chemistry students
Mallory Pickett
A classroom session during the "Greener Solutions" course offered at the Berkeley Center for Green Chemistry.

How could the laccase enzyme found in plants and fungi help Levi Straus & Co. keep a sharp crease in their brand of wrinkle-free khakis?

It’s one replacement for formaldehyde in permanent press fabrics investigated by an interdisciplinary group of University of California, Berkeley graduate students taking the Greener Solutions course offered by the Berkeley Center for Green Chemistry.

After some additional bench research, the enzyme proved more promising as an alternative fabric dye. Still, the semester-long process of searching for greener solutions to hazardous chemicals, entering its sixth year, is bending the efforts of talented young researchers toward sustainability challenges relevant to companies making everything from electronics to personal care products, building materials, furnishings, polymers and textiles.

Every fall semester, teams of graduate students tackle a challenge posed by a company in search of a safer way of making its products. Partner companies are at the leading edge of sustainability — usually those looking for a safer chemical or material in a particular application, in advance of new regulation.

Over the summer, faculty work with corporate partners to scope the challenge, designing a project that students can accomplish in a semester. Next come interdisciplinary teams of three-five graduate students. Teams typically include at least one chemist, an environmental health scientist and an engineer, plus the occasional microbiologist or architect.

Students start by identifying the core function served by the chemical of concern, such as preservatives, surfactants, mosquito repellants or colorants. Participating companies then help students understand the technical constraints of the system they’re working in. What is the production process a product undergoes? How must it perform? What are its highest priority design attributes?

Teams research the materials used, how their constituent chemicals interact and the industrial processes relevant to the challenge.

Seeking solutions

Once technical and performance criteria are clear, students begin their search for alternatives. They might identify promising replacements that already exist, but they also look farther afield, often turning to biology and asking, "How is this function achieved in nature?"

Although nature includes plenty of toxic substances, from the urushiol found in poison oak to arsenic and snake venom, biology has also made the brilliant color in paprika and the stunningly strong composite that is spider silk. In all, biology offers a few billion years of innovation to plumb for design inspiration.

When student teams identify a promising biological material or process, a series of translational steps remain in which they zoom in to understand the constituent chemistry and then abstract from there, working from the principles they identify in biology to design a solution that is bio-inspired (rather than one that uses the biological material directly, which would qualify as bio-utilization).

For example, one team identified possible approaches to designing a safer biopolymer resin for additive manufacturing (3-D printing) by investigating how lobsters and shrimp build their shells from chitosan. Another team, investigating safer alternatives to the diisocyanates that serve as cross-linkers in spray polyurethane foam insulation, researched adhesives that model the process used by mussels to adhere to rocks in intertidal zones.

Faculty encourage teams to spend a few weeks in a creative design space, not narrowing the field too quickly. There, they might identify readily available alternatives that a partner company could adopt fairly easily. Students often come up with several intriguing possibilities that could take years to develop before they are ready for large-scale production.

Once they’ve identified a handful of promising alternatives, the student teams perform a hazard assessment, comparing hazards associated with the existing product with hazards that might be associated with their alternatives.

We teach students to use criteria in the publicly available GreenScreen for Safer Chemicals. While a full GreenScreen assessment is beyond the scope of the course, students learn a systematic approach for finding as much hazard information as possible, extending their analysis across the full lifecycle of the chemicals and materials in their solutions.

In general, we ask students to identify inherently safer solutions, incorporating exposure information where relevant, with an aim to reduce the overall hazards associated with a product or manufacturing process.

Ahead of the competition

Individual companies offer up new challenges, but as an academic course in a public university, all projects are conducted without the need for non-disclosure agreements.

From the beginning, the goal is to identify pre-competitive issues and scope challenges to address a problem commonly encountered by an industry sector. How, for example, could we design safer surfactants to remove oily soil at the low temperatures that would confer vast energy savings?

Students are then free to discuss and publish their work, and partner companies generally work with others in their sector to amplify impact by sharing solutions across their industries.

Some projects have produced results that soon could show up in consumer products.

In 2014, one student team investigated safer preservatives for use in personal care products. With Seventh Generation, Beautycounter and Method Home, they looked for safer antimicrobials for products such as laundry detergent, shampoo and face creams. They identified several classes of natural compounds with antimicrobial activity, including terpenes found in pine trees, peptides in milk, fatty acids in fish oils and flavonoids found in tea leaves.

In addition to identifying promising classes of compounds to investigate further as preservatives, they also suggested several creative formulation approaches. Students summarized their analyses of the technical feasibility, health and environmental performance of each proposed solution, then presented their findings in reference to priorities at each partner company.

This is typically where the semester ends, with a road map that describes a range of interesting possibilities partner companies can pursue. There may be suggestions for bench-top research, but that doesn’t take place during the course.

In this case, however, inspired by some molecules and antimicrobial mechanisms identified in the course, several members of this group went on to perform laboratory work alongside scientists at the U.S. Department of Agriculture in Richmond, California. There, they identified octyl gallate as a potentially safer and more effective preservative for use in personal care products, building materials and food packaging. And they proposed a framework for iteratively evaluating both the function and safety of alternative preservatives.

Students will take on a new set of challenges in the fall, and we’re always looking for new challenges inside companies. Who knows? We might just find the right use for that fungal enzyme yet.