3D printing has grown into a multi-billion dollar industry in part because of the consumer 3D printing market, which has grown to the point that most schools, libraries, and a surprising number of homes sport a 3D printer. This explosion was driven in a large part by economics – you can normally 3D print products for less money than you can purchase them . Many databases sport millions of free and open source designs you can download and print at home . 3D printing products for yourself is actually good for the environment , but as anyone who has owned one of these printers knows, they do not always print perfectly. When that happens you end up with plastic waste that can be recycled using a distributed recycling and additive manufacturing method (e.g. build a recyclebot to turn the plastic waste back into filament). This can only happen about 5 times before the plastic starts to lose mechanical integrity. In a new study , scientists proposed a new solution for this – turn it into food and eat it.

3D Printing Waste to Protein Food

Polylactic acid (PLA) is the most common extrusion-based distributed 3-D printing material. It is the material you see being made into toys for Christmas . Unfortunately, large amounts of PLA are wasted from failed prints, support materials, material changes for multi-color printing, and poorly designed iterative prototypes.

To overcome these challenges at the end-of-life of PLA 3-D printing material, this preliminary study explores a new approach that uses hydrolysis of PLA to create a candidate single-cell protein (SCP) feedstock that can be converted to human-edible food after required safety validation. Protein is of particular interest now with huge amounts being eaten by a new health-conscious public and GLP-1 drug users.

In the study , three concentrations of sodium hydroxide were tested for their ability to perform hydrolysis on PLA at room temperature using readily accessible equipment and chemicals. The solution is then neutralized, and yeast you can buy at the grocery store was grown in an open-source bioreactor, dried, and quantified to determine the preliminary yield of single-cell protein.

Results: Getting Protein from 3D Printing Waste is Possible But More Studies Needed

The results show a clear positive correlation between PLA degradation efficiency with higher sodium hydroxide concentration and yeast biomass production. The average performance of 1/3rd sodium hydroxide to PLA treatment resulted in an 8.5-fold yeast biomass increase.

In summary, the current bench-scale process has proven technically viable and may be an economically justified method of yeast production on the household scale using PLA waste as a starting material. More experiments are needed to nail down the chemistry and ensure it is safe to eat. The dominant cost is energy, not reagents, which also lends the positive early results to future safety investigation using a scaled-up open source bioreactor.

Just because we can make something like 3D printing plastic into food, does not mean that we should. In an emergency this provides another pathway to human edible food, but outside of disasters even if we can turn plastic into food at a low cost people may choose more traditional food. The last remaining question would be – would you eat it?