Researchers produce more biodegradable plastic compostable at home and industrial settings

The team worked with polylactic acid (PLA). It has been used in packaging for over a decade, and is derived from plant sugars rather than petroleum.

When managed properly, PLA’s waste byproducts are all natural – water, carbon dioxide and lactic acid. Additionally, PLA can biodegrade in industrial composters. These composters create conditions, such as high temperatures, that are more conducive to breaking down bioplastics.

Developing home composting may sound unreasonable to some people as microbes cannot attack and consume PLA normally, it has to be broken down where microbes can utilize it as food.

The team’s experience showed that PLA can sit around for 20 days before microbes start digesting it in industrial composting conditions.

The picture shows Pooja Mayekar, a doctoral students of the team, explained how compostable polymers composted.

To get rid of that lag time, which also allows the possibility of home composting, the team integrated a carbohydrate-derived material called thermoplastic starch into PLA. The starch provides composting’s microbes something they can more easily chow down on while the PLA degrades.

Postdoctral researcher Anibal Bher had already been formulating different PLA-thermoplastic starch blends to observe how they preserved the strength, clarity and other desirable features of regular PLA films.

The picture shows a close-up of bioreactors which has been built to conduct biodegradation experiments. The bioreactors are essentially large glass jars with tubing to measure the gases produced during composting.

Doctoral student, Wanwarang Limsukon, Bher and Mayekar, observed how different films broke down throughout the composting process when carried out at different conditions.

“Different materials have different ways of undergoing hydrolysis at the beginning of the process and biodegrading at the end,” Limsukon explained.

The picture shows the conditioned chamber which researchers can regulate temperature, humidity and airflow, while measuring the carbon dioxide produced by microbes as they digest materials in the bioreactors.