LAHB: A bioplastic that may solve marine plastic pollution problem
An environment-friendly plastic lost over 80% of its mass after 13 months underwater real-time deep-sea conditions
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Researchers submerged LAHB films at a depth of 855 m near Hatsushima Island to test real-world deep-sea biodegradation. After 13 months, the LAHB plastic lost over 80% of its mass, showing its potential as a safer alternative to conventional plastics that persist in marine ecosystems.
view moreCredit: Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
Researchers have demonstrated a new eco-friendly plastic that decomposes in deep ocean conditions. In a deep-sea experiment, the microbially synthesized poly(d-lactate-co-3-hydroxybutyrate) (LAHB) biodegraded, while conventional plastics such as a representative bio-based polylactide (PLA) persisted. Submerged 855 meters underwater, LAHB films lost over 80% of their mass after 13 months as microbial biofilms actively broke down the material. This real-world test establishes LAHB as a safer biodegradable plastic, supporting global efforts to reduce marine plastic waste.
Despite the growing popularity of bio-based plastics, plastic pollution remains one of the world’s most pressing environmental issues. According to the OECD’s Global Plastics Outlook (2022), about 353 million metric tons of plastic waste were produced globally in 2019, with nearly 1.7 million metric tons flowing directly into aquatic ecosystems. Much of this waste becomes trapped in large rotating ocean currents, known as gyres, forming the infamous “garbage patches” found in the Pacific, Atlantic, and Indian Oceans.
To tackle this, researchers have been searching for plastics that can be degraded more reliably in deep-sea environments. One promising candidate is poly(d-lactate-co-3-hydroxybutyrate) or LAHB, a lactate-based polyester biosynthesized using engineered Escherichia coli. So far, LAHB has shown strong potential as a biodegradable polymer that breaks down in river water and shallow seawater.
Now, in a study made available online on July 1, 2025, and published in Volume 240 of the journal Polymer Degradation and Stability on October 1, 2025, researchers from Japan have shown for the first time that LAHB can also get biodegraded under deep-sea conditions, where low temperatures, high pressure, and too limited nutrients make breakdown of plastic extremely difficult. The study was led by Professor Seiichi Taguchi at the Institute for Aqua Regeneration, Shinshu University, Japan, together with Dr. Shun'ichi Ishii from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan and Professor Ken-ichi Kasuya from Gunma University Center for Food Science and Wellness, Japan.
“Our study demonstrates for the first time that LAHB, a microbial lactate-based polyester, undergoes active biodegradation and complete mineralization even on the deep-sea floor, where conventional PLA remains completely non-degradable,” explains Prof. Taguchi.
The research team submerged two types of LAHB films—one containing about 6% lactic acid (P6LAHB) and another with 13% lactic acid (P13LAHB)—alongside a conventional PLA film for comparison. The samples were submerged at a depth of 855 meters near Hatsushima Island, where deep-sea conditions, cold temperatures (3.6 °C), high salinity, and low dissolved oxygen levels make it hard for microbes to degrade plastic.
After 7 and 13 months of immersion, the LAHB films revealed clear signs of biodegradation under deep-sea conditions. The P13LAHB film lost 30.9% of its weight after 7 months and over 82% after 13 months. The P6LAHB film showed similar trends. By contrast, the PLA film showed no measurable weight loss or visible degradation during the same period, underscoring its resistance to microbial degradation. The surfaces of the LAHB films had developed cracks and were covered by biofilms made up of oval- and rod-shaped microbes, indicating that deep-sea microorganisms were colonizing and decomposing the LAHB plastic. The PLA film, however, remained completely free of biofilm.
To understand how the plastic decomposes, the researchers analyzed the plastisphere, the microbial community that formed on the plastic’s surface. They found that different microbial groups played distinct roles. Dominant Gammaproteobacterial genera, including Colwellia, Pseudoteredinibacter, Agarilytica, and UBA7957, produced specialized enzymes known as extracellular poly[3-hydroxybutyrate (3HB)] depolymerases. These enzymes break down long polymer chains into smaller fragments like dimers and trimers. Certain species, such as UBA7959, also produce oligomer hydrolases (like PhaZ2) that further cleave these fragments, splitting 3HB–3HB or 3HB–LA dimers into their monomers.
Once the polymers are broken down into these simpler building blocks, other microbes, including various Alpha-proteobacteria and Desulfobacterota, continue the process by consuming the monomers like 3HB and lactate. Working together, these microbial communities ultimately convert the plastic into carbon dioxide, water, and other harmless compounds that ideally return to the marine ecosystem.
The findings of this study fill a critical gap in our understanding of how bio-based plastics degrade in remote marine environments. Its proven biodegradability makes it a promising option for creating safer, more biodegradable materials.
“This research addresses one of the most critical limitations of current bioplastics—their lack of biodegradability in marine environments. By showing that LAHB can decompose and mineralize even in deep-sea conditions, the study provides a pathway for safer alternatives to conventional plastics and supports the transition to a circular bioeconomy,” says Prof. Taguchi.
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About Shinshu University
Shinshu University is a national university founded in 1949 and located nestling under the Japanese Alps in Nagano known for its stunning natural landscapes.
Shinshu University was selected for the Forming Japan’s Peak Research Universities (J-PEAKS) Program by the Japanese government. This initiative seeks to promote the formation of university consortia that will enhance research capabilities across Japan.
Our motto, "Powered by Nature - strengthening our network with society and applying nature to create innovative solutions for a better tomorrow" reflects the mission of fostering promising creative professionals and deepening the collaborative relationship with local communities, which leads to our contribution to regional development by innovation in various fields. We’re working on providing solutions for building a sustainable society through interdisciplinary research fields: material science (carbon, fiber and composites), biomedical science (for intractable diseases and preventive medicine) and mountain science, and aiming to boost research and innovation capability through collaborative projects with distinguished researchers from the world. For more information visit https://www.shinshu-u.ac.jp/english/ or follow us on X (Twitter) @ShinshuUni for our latest news.
Journal
Polymer Degradation and Stability
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Unveiling deep-sea biodegradation of microbially produced lactate-based polyester (LAHB) via plastisphere metagenomics and metatranscriptomics
Article Publication Date
21-Jul-2025
Call for bold action at upcoming Global Plastics Treaty Talks (INC-5.2)
Cambridge University Press
You are invited to a briefing event hosted by the journal Cambridge Prisms: Plastics, which is published by Cambridge University Press.
Date: 24 July 2025
Time: 2 pm (BST) / 9 am (EDT)
Platform: Zoom
Access Link: https://cup.org/4kJTxWn
RSVP Contact: Rosalind Moran, press@cambridge.org
As the world prepares for the final round of negotiations on a legally binding global plastics treaty (INC-5.2), from 5-14 August 2025, over 60 academic experts have stepped forward to outline exactly what they believe the treaty must include, and why this moment is a potential turning point in environmental policy.
Cambridge Prisms: Plastics publishes leading research that directly explores the urgent and major societal challenges posed by plastics and examines possible solutions.
The journal has convened this event as a rare and urgent intervention, launching a collection of open letters from leading scientists across disciplines and continents into the debate over what could become the most significant global environmental agreement since the Paris Climate Accord.
The authors are not merely pointing to the problem. They are offering clear, evidence-based, and solutions-driven recommendations on everything from human health impacts and toxic chemical regulation to production caps and the structural inclusion of affected communities.
In Brief:
- Who? A panel of five plastics expert scientists, chaired by Professor Steve Fletcher, Editor-in-Chief of Cambridge Prisms: Plastics and Director of the Revolution Plastics Institute
- What? A major academic intervention in the Global Plastics Treaty process - solution-focused, justice-oriented, and backed by rigorous evidence.
- Why now? INC-5.2 in August represents the world’s final opportunity to secure a legally binding plastics treaty, or risk failure due to industry influence and political delay.
The confirmed speakers:
- Professor Maria Ivanova is Director of the School of Public Policy and Urban Affairs at Northeastern University in the US and a globally recognised expert in international environmental governance. She brings deep insight into the role of trade, diplomacy, and institutional design in building effective global treaties.
- Professor Max Liboiron is a leading thinker on Indigenous science and environmental justice. Based at Memorial University in Canada, their work challenges extractive approaches to research and policy, and champions governance models rooted in Indigenous rights and sovereignty.
- Professor Cressida Bowyer is Deputy Director of the Revolution Plastics Institute at the University of Portsmouth. Her research focuses on the intersections of plastic pollution, human health, and environmental justice, with an emphasis on arts-based engagement and inclusive policymaking.
- Professor Tony Walker is an environmental scientist at Dalhousie University in Canada, with deep expertise in microplastics, plastic pollution, and the circular economy. His work interrogates the structural drivers of the linear plastics system and identifies pathways for systemic transition.
- Professor Susanne Brander is an ecotoxicologist at Oregon State University. Her research explores the impacts of micro- and nanoplastics and plastic-associated chemicals on human and ecological health. She is a strong advocate for stronger global controls on hazardous chemicals in plastics.
What the briefing will cover:
- A shift in focus to human health: New evidence makes clear that plastic pollution is not just an environmental crisis, but a public health emergency - with microplastics and toxic chemicals linked to cancers, reproductive issues, and more.
- A just and inclusive treaty: The scientists call for meaningful inclusion of Indigenous Peoples, waste workers, and frontline communities.
- Safeguarding scientific integrity: Academics are calling for an independent science advisory body to ensure evidence-based decisions, free from corporate influence and greenwashing.
- High ambition vs delay: The letters call out the blocking tactics of low-ambition nations and propose flexible mechanisms so coalitions of ambitious countries can move forward, supported by proper finance and compliance tools.
- The urgency for binding action: Voluntary, fragmented approaches have failed. Scientists are demanding enforceable measures across the entire plastic lifecycle – from fossil fuel extraction to toxic additives and waste.
The authors will focus on:
- The role of Indigenous Peoples in the global plastics treaty
- How the global plastics treaty should address atmospheric microplastics
- The role of trade in managing plastic pollution and in the global plastics treaty
- The regulation of chemicals in the global plastic treaty
- How will the implementation of the global plastics treaty will be financed
- The implications of the global plastics treaty for agriculture and food safety
What’s new?
- INC-5.2 is the last scheduled meeting after a stalled process – and now, more than 100 countries are backing a strong, ambitious treaty.
- The academic community is united, vocal, and ready with concrete, science-backed proposals – not just warnings.
- This is a rare moment where academic voices are breaking through the noise to be heard at the centre of a global policymaking process.
These letters represent the scientific community’s clearest, boldest call yet for what the treaty must deliver. The future of plastics governance and our health, ecosystems, and climate, hangs in the balance.
To join the briefing
The briefing will be held on Zoom. Register via the following link: https://cup.org/4kJTxWn
You can pre-submit any questions on the registration form.
If you cannot attend, please register to receive a recording of the briefing.
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