What Are The Cons of Bioplastics?

Many of the benefits of bioplastics come with strings attached. Critics of bioplastics derived from food crops like corn or soybeans, for example, argue that their use in plastics diverts these crops from the food supply. They also point out that raising plants for bioplastics poses the same environmental hazards as large-scale agriculture, including pesticides and herbicides. To counter these criticisms, some bioplastic manufacturers use agricultural waste in their plastics. This approach not only puts waste to work but also provides an additional revenue stream for farmers. 

Like traditional plastics, the manufacture and shipping of bioplastic products use energy and fossil fuels, even if they themselves are not petroleum-based. And like conventional plastic, bioplastics designed as single-use products eventually end up in the waste stream. And that's where things can get complicated. 

What are Common Bioplastics Made of? 

The two most common bioplastics on the market are PLA (polylactic acid) and PHA (polyhydroxyalkanoate). PLA stems from plant sugars and starches, such as those found in corn or sugar cane. PHA comes from microorganisms that react with organic materials. Though both are more expensive than synthetic plastics, PLA is much cheaper than PHA and is used for disposable cutlery and packaging. PHA is also used for packaging, as a coating for the inside of paper cups, and in medical applications.