In a review recently published in the open access journal Materials, researchers investigated the potential of polylactic acid as a replacement material for single-use laboratory components.
Study: A review of polylactic acid as a replacement material for single-use laboratory components. Image Credit: Elpisterra/Shutterstock.com
Polymers are organic compounds that are linked together in long sequences. Synthetic polymers (plastics) have become commonplace in clothing, packaging, and other products due to their durability, low cost, and ease of manufacture. Single-use plastic equipment can be delivered pre-sterilized and discarded once contaminated, reducing the number of facilities and processes required in research labs and manufacturing plants.
However, this increases dependence on fossil fuels and the amount of non-biodegradable waste produced. Producing biodegradable or recyclable polymers from biomass waste from industry can have a number of environmental benefits, including reusing materials that would otherwise be wasted, reducing dependence on fossil fuels, and reducing pollution. environmental impact of eliminating plastic.
Stereoisomers of lactic acid. Image Credit: Freeland, B et al., Materials
About the study
In this study, the authors discussed the production of CO2 from plastic manufacturing alone, with 99% of all plastics derived from fossil fuels and those derived from renewable sources using food as a raw material in Europe. The potential use of bioplastics as a viable replacement for single-use laboratory consumables such as pipette tips, petri dishes and other items was illustrated.
The researchers looked at some of the most common polymers used in labware, as well as the prospect of replacing them with bioplastics, including polylactic acid (PLA). The material qualities of PLA, as well as potential functional improvements, were discussed. Finally, the standards and references for the evaluation of bioplastics for components of laboratory equipment have been developed.
The team provided a list of commonly used polymers for common objects, along with their general qualities. The usefulness of polyethylene terephthalate g copolyester (PETG), polystyrene (PS), polycarbonate (PC) and polypropylene (PP) polymers for single-use laboratory equipment was illustrated.
Examples of molecular configurations of PLA obtained by combining the two lactic acids. Image Credit: Freeland, B et al., Materials
Bioplastics would typically be three to four times more expensive to produce than petroleum-based equivalents. According to technical-economic study reports, PLA production prices ranged from €3.56/kg for a small capacity plant generating 10,624 t/year to €0.91/kg for a larger production facility. with a manufacturing capacity of 100,000 t/year.
Polyhydroxyalkanoates (PHAs), as an alternative bioplastic, had comparable production costs ranging from €1.1 to €5.24 per kg. The minimum retail price of PLA was €3/kg, implying that large-scale manufacturing of 100,000 t/year was needed to develop economically viable biopolymers.
In Europe, 29 million tonnes of plastic waste was collected in 2019. It is estimated that 32% of the waste was recycled, 43% was burned and 25% was sent to landfill. Life sciences are estimated to generate approximately 5.5 Mt of plastic waste each year, the majority of which is disposed of through cremation.
1 kg of recycled PET trays used in mushroom packaging with 85% recycled content had a carbon footprint of 1.538 kg CO2e. Renewable feedstock pathways, such as corn-based biopolymers generated with conventional energy, were the most widely anticipated biopolymer option, with the potential to reduce GHG emissions globally. industry by 25%, or 16 Mt of CO2y/y. The reactor had a normal operating time of about 1 hour, a vacuum pressure of 4 mbar, a temperature of 210°C and a catalyst quantity of 0.05% by weight of tin(II) octoate in food.
Tuning PLA properties with a variety of additives. Image Credit: Freeland, B et al., Materials
In conclusion, this study elucidated the properties of typical labware polymers, including PLA, as well as the standards for plastic labware. The qualities of PLA were limited in terms of temperature, brittleness and resistance to solvents; however, the mix of polymerized isomers to produce the level of crystallinity, the plastic, and the inclusion of plasticizers and other additives could all be adjusted. Although some items of commercial labware have been made from PLA, research on additive manufacturing of labware from PLA has also been done, and bioplastics for labware were not widely used.
Plastics have been observed to have two major sustainability shortcomings, namely reliance on non-renewable and environmentally harmful fossil fuels as a source and generation of non-degradable waste. The accumulation of waste and its entry into terrestrial, river and marine ecosystems has been observed as a major environmental concern. The authors pointed out that this has sparked interest in the development of sustainable bioplastics. They also mentioned that these plastics could be made from bio-waste, reducing dependence on fossil fuels while being biodegradable.
They believe that further research is needed to determine which types of PLA composites or PLA derivatives are appropriate for labware, as well as which items of labware they are suitable for.
Freeland, B., McCarthy, E., Balakrishnan, R., et al. A review of polylactic acid as a replacement material for single-use laboratory components. Papers 15(9) 2989 (2022). https://www.mdpi.com/1996-1944/15/9/2989