We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Estimation of kinetic constants in high-density polyethylene bead degradation using hydrolytic enzymes
AI summary Read the abstract
Researchers measured the degradation of high-density polyethylene microplastic beads by hydrolytic enzymes under varying temperatures and concentrations, finding that protease at thermophilic conditions removed up to 23% of bead mass in seven days, and developed a kinetic model predicting 70–95% removal under typical anaerobic digestion conditions.
Microplastic beads are an emerging contaminant that can cause serious environmental and public health problems. Potential bypass of microplastic beads from wastewater to sludge treatment systems is a key challenge in the conventional wastewater treatment process. Moreover, there are no systematic studies on microplastic bead degradation by hydrolytic enzymes that are rich in concentration within wastewater and sludge treatment processes (e.g., anaerobic digestion (AD)). In this study, lab-scale experiments were conducted to investigate the degradation of high-density polyethylene beads by hydrolytic enzymes (e.g., lipase) under various experimental conditions (e.g., temperature). In a 3-day batch experiment, protease was most effective in polyethylene bead degradation as 4.0% of the initial bead mass was removed at an enzyme concentration of 88 mg/L under thermophilic temperature (55 °C). It was also found that the increasing enzyme concentration and high temperature enhanced the polyethylene bead degradation. In a separate 7-day experiment with repeated doses of protease, 23.3% of the initial mass of beads was removed at thermophilic temperature, indicating that AD with a long retention time (e.g., 20 days) and heated temperature has a significant potential for polyethylene bead degradation. A mathematical model was developed and calibrated using the experimental results to estimate the kinetic constant of the high-density polyethylene bead reduction by an enzyme (k) and enzyme self-decay constant (k). The calibrated k ranged from 5.0 to 8.1× 10 L/mg/hr while k was 0.44-1.10 L/mg/hr. Using the calibrated model, degradation of polyethylene beads using a mixture of cellulase and protease was simulated, considering an interactive-decay reaction between the two enzymes. The calibrated model was used to simulate the polyethylene bead degradation in AD where 70-95% of the initial bead mass was removed at typical retention time under mesophilic digestion (37.5 °C). Based on the experimental and simulation results, it can be concluded that hydrolytic enzymes can be an efficient technology for large-scale high-density polyethylene bead removal applications.
More Papers Like This
Insights into the degradation of high-density polyethylene microplastics using microbial strains: Effect of process parameters, degradation kinetics and modeling
AI summary Read the abstract
Researchers tested several microbial strains for their ability to break down high-density polyethylene microplastics and developed models to predict degradation rates. Certain bacteria and fungi showed measurable ability to deteriorate the plastic surface over weeks of exposure. The study contributes to the development of biological approaches for remediating microplastic pollution in the environment.
Characterization of HDPE microparticles in sludge aerobic digestion and their influence on the process
AI summary Read the abstract
Researchers characterized high-density polyethylene microparticles in sludge from aerobic digesters, examining their size distribution, shape, and surface properties before and after treatment. The study provides data on how microplastics behave in biological sludge treatment and what fraction persists through the process.
Biodegradation of macro- and micro-plastics in environment: A review on mechanism, toxicity, and future perspectives.
AI summary Read the abstract
This review examined mechanisms, toxicology, and future perspectives for biodegradation of macro- and micro-plastics, cataloguing microbial species capable of polymer degradation, discussing enzymatic pathways, and identifying key limitations including slow degradation rates and the need for pretreatment to accelerate breakdown in environmental settings.
Biotechnological Aspects and Mathematical Modeling of the Biodegradation of Plastics under Controlled Conditions
AI summary Read the abstract
Mathematical models of plastic biodegradation kinetics under controlled conditions were reviewed and evaluated for their ability to capture the complex interplay of biological, physical, and chemical processes involved in plastic breakdown. The review identifies key modeling challenges and argues that better kinetic frameworks are needed to predict real-world plastic degradation rates and inform waste management strategies.
Microbial degradation of microplastics by enzymatic processes: a review
AI summary Read the abstract
Microorganisms including bacteria, fungi, and algae produce enzymes capable of degrading microplastics, offering a biologically safe remediation pathway that avoids secondary toxic byproducts. Advancing our understanding of specific enzymes and their degradation mechanisms could unlock scalable solutions for eliminating persistent microplastic contamination from marine and terrestrial environments.
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.