Mexican researchers have found a way to turn cactus leaves into non-toxic and biodegradable material with properties similar to plastic. This innovation offers a promising solution to one of the world’s biggest pollution conundrums caused by toxic and non-biodegradable plastic.

The pulp of the prickly pear cactus is strained to obtain a juice. It is then mixed with non-toxic additives and stretched to produce sheets that are coloured with pigments and folded to form different types of packaging material. This material obtained is non-toxic, environment-friendly and biodegradable.

Biodegradable plastic

* Biodegradable plastics are those that can be decomposed by the action of living organisms, usually bacteria.

* There are two basic classes of biodegradable plastics - bioplastics, whose components are derived from renewable raw materials, and plastics made from petrochemicals containing biodegradable additives that enhance biodegradation.

Applications

* Biodegradable plastics are commonly used for disposable items such as packaging, crockery, cutlery and food service containers. In principle, they could replace many applications for petroleum-derived plastics, but cost and performance remain problematic.

* Their usage is financially favorable only if supported by specific regulations limiting the usage of conventional plastics. Typical is the example of Italy, where biodegradable plastic bags have been compulsory since 2011 with the introduction of a specific law.

Regular vs biodegradable plastic

* After formation, regular plastics hold carbon. When they are disposed of and begin to decompose or when they are melted, that carbon is then released into the atmosphere. Biodegradable plastics do not release carbon, because no carbon is involved in the manufacturing process. Methane and other forms of pollutants could also be released from traditional plastic when they are recycled and burned. This is not the case with biodegradable plastics, which do not contain those polluting materials.

* One of the positive aspects of biodegradable plastics is that they are able to be broken down by naturally occurring bacteria, which again will be beneficial to the environment.

* Aside from a slightly higher cost to produce, biodegradable plastics hold many advantages over standard plastics, with a lesser impact on the environment being one of its greatest advantages.

Pros and cons

* Biodegradable plastics do have some drawbacks. For example, they do not decompose unless they are disposed of properly, meaning that biodegradable plastics must be treated similarly to compost.

* The natural breakdown of plastic will not occur if it is simply tossed in a landfill with other trash. This is something that concerned citizens will need to be mindful of. Some scientists also suggest that greenhouse gases are locked within the plastic and are released into the atmosphere when composted. However, everything used in the production of biodegradable plastic is natural. As such, these plastics do not contain harmful chemicals and materials that traditional plastics do.

* Some biodegradable materials do contain small pieces of metal. There is concern that when biodegradable plastics break down, those metals will be released into the environment. However, to date there is no evidence of that causing any significant issues.

* The benefits would seem to outweigh any potential drawbacks, but the question of whether or not biodegradable plastics will someday replace traditional plastic is still a matter of debate.