The word "plastic" has become deeply ingrained in our daily lives. From the morning coffee cup to electronic devices used before bedtime, plastic is ubiquitous. With advantages like lightweight, durability, and low cost, it has significantly improved modern living standards and become an indispensable material of our era.

However, like two sides of a coin, widespread plastic use has brought unprecedented environmental challenges. While enjoying plastic's convenience, we also suffer from "white pollution." Imagine vast ocean garbage patches, once-beautiful beaches covered in plastic waste, and even microplastics potentially present in the air we breathe—these aren't dystopian sci-fi scenarios but our current reality.

Statistics show global waste generation reaches 1.1 gigatons annually (equivalent to 1.1 billion tons!), with plastics accounting for a staggering 10%. This means over 100 million tons of plastic waste enter the environment yearly, creating enormous ecological pressure. This pollution contaminates soil and water, endangers wildlife, and ultimately enters our bodies through the food chain.

Biodegradable plastics are defined as materials that microorganisms (like bacteria, fungi, algae) can break down into carbon dioxide, water, and biomass in natural environments. Unlike traditional plastics, this decomposition isn't mere physical fragmentation but actual chemical breakdown through microbial enzymes.

Common biodegradable plastics include:

• Polylactic Acid (PLA): Made from fermented plant starches (corn, sugarcane), used in food packaging and medical materials.
• Polyhydroxyalkanoates (PHA): Microbial-produced polyesters for packaging and agricultural films.
• Polybutylene Adipate Terephthalate (PBAT): Aliphatic-aromatic copolyester combining biodegradability with strong mechanical properties.
• Polybutylene Succinate (PBS): Aliphatic polyester for packaging and agricultural applications.
• Cellulose-based Plastics: Derived from plant cell walls, offering renewability and biodegradability.

Among biodegradable options, PBAT stands out as a hybrid aliphatic-aromatic copolyester that balances biodegradability with performance. Commercialized since 1998, its global production has expanded rapidly due to competitive costs and versatility in packaging, agriculture, and textiles.

PBAT production involves polymerizing 1,4-butanediol (BDO), adipic acid (AA), and terephthalic acid (PTA)—all petroleum-derived, making PBAT only partially bio-based. Its degradation reverses this process: ester bonds hydrolyze into water-soluble oligomers, which microbes further break down into CO₂, water, and biomass.

Emerging research suggests PBAT's degradation products may be more toxic than the original microplastics. Quantum chemical calculations (using Gaussian16 software at M06-2X/6–311+g(2d,p) level) reveal:

• Aromatic compounds (PBAT, TPA, TBT, TBTBT) act as strong electron acceptors, similar to reactive oxygen species, potentially oxidizing biomolecules like DNA.
• TBTBT—a key degradation intermediate—shows the highest electron-accepting capacity, indicating possible toxicity.
• Aliphatic degradation products (BDO, AA) are less concerning as electron donors.

Experimental studies corroborate these findings. PBAT byproducts inhibit plant photosynthesis and growth while increasing oxidative stress. Notably, research often overlooks cumulative effects of PBAT and its degradation intermediates like TBT/TBTBT, potentially underestimating risks.

While biodegradable plastics like PBAT offer partial solutions to plastic pollution, their degradation products' toxicity demands rigorous evaluation. Future priorities should include:

• Comprehensive degradation pathway studies across environmental conditions
• Multispecies toxicity assessments (microorganisms to humans)
• Systemic environmental risk modeling
• Development of safer biodegradable alternatives
• Policy frameworks ensuring responsible production and disposal

Biodegradable plastics aren't a panacea. Their adoption must complement—not replace—reduction, reuse, and recycling strategies. Only through balanced innovation and regulation can we truly address the complex legacy of plastic pollution.