Polylactic acid synthesis, biodegradability, conversion to microplastics and toxicity: a review

Abstract

Global pollution by plastics derived from petroleum has fostered the development of carbon–neutral, biodegradable bioplastics synthesized from renewable resources such as modern biomass, yet knowledge on the impact of bioplastics on ecosystems is limited. Here we review the polylactic acid plastic with focus on synthesis, biodegradability tuning, environmental conversion to microplastics, and impact on microbes, algae, phytoplankton, zooplankton, annelids, mollusk and fish. Polylactic acid is a low weight semi-crystalline bioplastic used in agriculture, medicine, packaging and textile. Polylactic acid is one of the most widely used biopolymers, accounting for 33% of all bioplastics produced in 2021. Although biodegradable in vivo, polylactic acid is not completely degradable under natural environmental conditions, notably under aquatic conditions. Polylactic acid disintegrates into microplastics faster than petroleum-based plastics and may pose severe threats to the exposed biota.

Towards a Sustainable Circular Economy: Algae‐Based Bioplastics and the Role of Internet‐of‐Things and Machine Learning

“…For instance, research has been undertaken to combine PLA with hydrophilic and hydrophobic polymers [89], aiming to enhance its mechanical properties and degradability, showing that multiple strategies can be employed to overcome the vulnerability of PLA to UV radiation. Researchers have investigated combining PLA with hydrophilic and hydrophobic polymers to address this issue in order to enhance its mechanical properties and degradability [89]. In addition, using compatibilizers improves the efficacy of PLA blends and composites, thereby increasing their application potential [89].…”

“…Researchers have investigated combining PLA with hydrophilic and hydrophobic polymers to address this issue in order to enhance its mechanical properties and degradability [89]. In addition, using compatibilizers improves the efficacy of PLA blends and composites, thereby increasing their application potential [89].…”

Aluminum-Containing Heterobimetallic Complexes as Versatile Platforms for Homogeneous Catalysis

“…Ring-opening polymerization (ROP) of lactides yields biodegradable and biocompatible poly­(lactic) acid (PLA). PLA is an important synthetic biodegradable polymer with broad utility in developing packaging materials and pharmaceutical and biological applications . The polymerization of lactides by alkoxide complexes, including those of aluminum, has been extensively studied. , The general mechanism for ROP of lactides initiates with the coordination of the electron-rich lactide carbonyl group to the metal center, activating it toward nucleophilic attack of the initiating group or polymeric moiety (Figure ).…”

“…Ring-opening polymerization (ROP) of lactides yields biodegradable and biocompatible poly(lactic) acid (PLA). PLA is an important synthetic biodegradable polymer with broad utility in developing packaging materials 29 and pharmaceutical and biological applications. 30 The polymerization of lactides by alkoxide complexes, including those of aluminum, has been extensively studied.…”

Protein fibrillation and hybridization with polysaccharides enhance strength, toughness, and gas selectivity of bioplastic packaging

“…10,11 Bioplastics, which are biobased or biodegradable materials, are emerging worldwide as more environmentally friendly candidates for the replacement of traditional petrochemicalbased plastics, 12,13 such as polyvinylchloride and polyethylene terephthalate, which are causing severe environmental pollution, particularly with accumulation in different ecosystems. 14 Recently, studies have found that even biodegradable plastics, such as polylactic acid (PLA) 15 and polyhydroxybutyrate (PHB), 16 cannot be completely degraded, and the resulting microplastics cause environmental pollution and biological hazards. When the bioplastic materials are biopolymers generated from food industry waste or underutilized sources of biomacromolecules (proteins, lipids, or polysaccharides), which are edible and biodegradable, they can be used as edible lms and/or coatings.…”