Intelligent Technologies, Enzyme-Embedded and Microbial Degradation of Agricultural Plastics

Abstract

This review appraised current research on enzyme-embedded biodegradable agricultural plastics and microbial degradation, given that the increased use of fossil-fuel-based plastics in agriculture involved significant environmental tradeoffs. Over 370 million tons of plastics were produced in 2019, releasing over 400 million tons of greenhouse gases during production, transportation, consumption, burning, and exposure to sunlight biodegradation. Less than 10% of bags are recycled at the end of their life, leading to environmental pollution. Thus, it is imperative to summarize studies that have suggested solutions of this problem. The scoping review approach was preferred, given that it established current practices and uncovered international evidence on bio-based solutions and conflicting outcomes. Bioplastics with low greenhouse warming potential had a small market share (approximately 1%). The accumulation of fossil-fuel-based plastics and poor post-use management releases mercury, dioxins, furans, and polychlorinated biphenyls (PCBs). Enzyme-embedded polymers degrade fast in the environment but lack the desired mechanical properties. Even though polylactic acid (PLA) and other bioplastics are better alternatives to synthetic polymers, they persist in the environment for years. Fast degradation is only practical under special conditions (elevated temperatures and humidity), limiting bioplastics’ practical benefits. The research and development of plastics that could degrade under ambient conditions through enzyme-catalyzed reactions and soil-inoculated microbes are ongoing. However, there are no guarantees that the technology would be profitable in commercial agriculture. Other limiting factors include the geographical disparities in agricultural plastic waste management. Future perspectives on the waste management of agricultural plastics require smart technologies, such as artificial intelligence (AI), machine learning (ML), and enzyme-embedded plastics that degrade under ambient conditions. The replacement of synthetic plastics with polylactic acid and polycaprolactone/Amano lipase (PCL/AL) composite films would offset the negative ecological effects. A major drawback was the slow research and development and commercial adoption of bio-based plastics. The transition to bioplastics was resource- and time-intensive.

Enzymatic Degradation Behavior of Self-Degradable Lipase-Embedded Aliphatic and Aromatic Polyesters and Their Blends

“…Since the past decade, the novel approach of lipase-embedding into the polymer matrix has been developed as an alternative to externally added lipase degradation common tests . This embedded enzymatic degradation or self-degradation can have potential applications in agriculture, as many biopolyesters commonly exhibit limited environmental degradation . Enzyme embedding started with the preparation of CalB-embedded PCL films via the solvent-casting method from toluene, leading to complete degradation of the films in 24 h (for a CalB content of 6.5 wt %) and 17 days (1.6 wt %) .…”

Machine Learning Based Prediction of Enzymatic Degradation of Plastics Using Encoded Protein Sequence and Effective Feature Representation

“…5 Conventional mechanical and chemical recycling either lead to loss of plastic properties or require high energy input and expensive reagents. 6,7 In contrast, biological enzymes, with high efficiency under mild reaction conditions, degrade plastics into monomers which can then be recovered to synthesize new plastic products for achieving a circular economy. 8−10 Significant research progress has been made recently in discovering plastic-degrading enzymes, 11 and there is a growing interest in identifying new plastic-degrading enzymes with desirable functionalities by exploring the ever-increasing number of putative enzyme sequences.…”

“…Plastics are extensively used globally, but improper handling of plastic waste has caused severe environmental problems. − Treating and recycling postconsumer plastics is critically important for environmental protection and waste valorization . Conventional mechanical and chemical recycling either lead to loss of plastic properties or require high energy input and expensive reagents. , In contrast, biological enzymes, with high efficiency under mild reaction conditions, degrade plastics into monomers which can then be recovered to synthesize new plastic products for achieving a circular economy. − …”

UV Light Degradation of Polylactic Acid Kickstarts Enzymatic Hydrolysis

“…As the first step in total biodegradation of plastics, enzymatic hydrolysis results in the cleavage of polymers chains into monomers, dimers, and oligomers capable of being mineralized by microorganisms. , Given the importance of enzymatic hydrolysis for total biodegradation, it is the process that this study tracks to evaluate biotic degradation. Further, measuring enzymatic hydrolysis is the prevailing approach to evaluate biodegradability within the literature. ,,,− However, there exists a gap within current knowledge of environmental degradation that encapsulates both abiotic and biotic factors. Herein, this study demonstrates the relationship between photo- and biodegradation in PLA and reveals that rather than crystallinity hindering biodegradation, decreases in polymer molecular weight boost biodegradation with photoaging.…”