{"id":9415,"date":"2025-04-02T08:52:17","date_gmt":"2025-04-01T23:52:17","guid":{"rendered":"https:\/\/www.elsi.jp\/?post_type=news_events&p=9415"},"modified":"2025-10-11T11:37:42","modified_gmt":"2025-10-11T02:37:42","slug":"plastic_straw_waste_polyester_microdroplets","status":"publish","type":"news_events","link":"https:\/\/www.elsi.jp\/en\/news_events\/highlights\/2025\/plastic_straw_waste_polyester_microdroplets\/","title":{"rendered":"How to convert plastic straw waste into polyester microdroplets with enzyme engineering and prebiotic chemistry"},"content":{"rendered":"

A collaborative study led by researchers at ELSI and National Central University in Taiwan discovered a method to convert plastic straw waste into polyester microdroplets potentially useful for drug delivery methods. This novel biorecycling method combines enzyme engineering and prebiotic chemistry, first converting polylactic acid straws into lactic acid monomers through enzymatic activity, followed by addition of malic acid and subsequent polymerization into poly(malate-co-lactate) through dehydration synthesis.<\/strong><\/p>\n

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Image 1. A scheme of the novel biorecycling strategy discovered in this study. Credit: Ming-Jing He<\/div>\n

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Non-reusable plastics are a major source of waste around the world, and new methods to recycle this waste into useful materials are a major focus of current research in fields focusing on biorecycling and green chemistry. One type of plastic commonly used in society is polylactic acid, which is used mainly due to its biodegradability and synthetic facility. It also turns out that polylactic acid is also a plausible polymer on early Earth! In fact, polylactic acid is believed to have been formed on early Earth through simple heating and drying of lactic acid, a monomer commonly found in meteorites or other primitive reaction product mixtures. These prebiotically synthesised polylactic acid polymers have in fact been shown to assemble into membraneless droplets, proposed to be protocell models, upon rehydration; polyester droplets of certain composition have even been used in modern drug delivery applications! Thus, polylactic acid appears to be a key molecule connecting modern biology with prebiotic chemistry.<\/p>\n

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\u201cHow can we use the lessons that we learned from prebiotic chemistry to help with biorecycling?\u201d you may ask. Well, prebiotic chemistry is mostly aqueous, and since it\u2019s possible to produce polyester microdroplets from lactic acid monomers, if we can somehow convert polylactic acid in straw waste into lactic acid monomers, then it could be possible to then subsequently produce polyester microdroplets from straw waste! The labs of Assistant Professor Po-Hsiang Wang of National Central University (NCU), experts in biochemistry and bioengineering, and ELSI\u2019s Specially Appointed Associate Professor Tony Z. Jia, experts in prebiotic chemistry and biophysics, thus sought to demonstrate the plausibility of converting unusable plastic straw waste into droplets that could be relevant to biomedicine.<\/p>\n

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Thus, former Master\u2019s student Ming-Jing He (NCU) began work on this project as the main experimental lead through a support grant by the ELSI Research Exchange Programme for collaborative research. First, plastic straw waste was successfully hydrolyzed into lactic acid monomers through two different methods: high-temperature alkaline reactions and proteinase K enzymatic activity. Both techniques appeared to result in fairly good product yields, but the proteinase K strategy was chosen as the conditions required for the high-temperature alkaline reactions were considered too harsh and not \u201cgreen\u201d enough. Following acquisition of straw waste-origin lactic acid monomers, He then added malic acid, another prebiotically plausible monomer, and subjected the mixture to dehydration synthesis over a few days to acquire poly-lactate-co-malate (PMALA) gels; these gels could then be assembled into membraneless PMALA droplets upon rehydration. While the PMALA synthesis reaction itself did not require a catalyst to push the reaction forward, a minimal amount of tin chloride was added to speed up the reaction slightly.<\/p>\n

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\u201cThe entire process of converting polylactic acid straw waste to lactic acid monomers, and then to PMALA droplets (after addition of malic acid) could be scaled up, suggesting that with more optimization, the proof-of-concept demonstration shown in this study could be applied commercially,\u201d says Wang, who will moving to the Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency of Science, Technology, and Research (A*STAR) in April, 2025.<\/p>\n

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Jia adds, \u201cas prebiotic chemistry is inherently green, often utilising aqueous-based chemistries, more and more collaborations between green chemists and prebiotic chemists could lead to more interesting studies and development of novel biorecycling techniques!\u201d<\/p>\n

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We note that the ELSI Research Exchange Programme no longer supports visits by Master\u2019s course students to ELSI from fiscal year 2024. As He had graduated by the time the manuscript was submitted, Master\u2019s student Kun-Ti Liao (NCU) completed instrumental final experiments to push this manuscript over the finish line.<\/p>\n

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Image 2. The main contributors of the study. Ming-Jing He (co-first author) was the experimental lead, and performed many experiments at ELSI during a research visit for her Master\u2019s thesis sponsored by the ELSI Visitor (Brain Exchange) Program. Tony Z. Jia and Po-Hsiang Wang (co-corresponding authors) developed the idea for this collaborative study through various research exchanges and visits over the years. Credit: Ming-Jing He and Tony Z. Jia<\/div>\n

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Image 3. Polylactic acid straw fragments. Credit: Ming-Jing He and Kun-Ti Liao<\/div>\n

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<\/div>\n
\n\n\n\n\n\n\n\n\n
Journal<\/td>\nACS Applied Polymer Materials<\/td>\n<\/tr>\n
Title of the paper<\/td>\nLow-temperature green synthesis and assembly of poly(malate-co-lactate) gel-based microdroplets from polylactate plastic straw waste<\/td>\n<\/tr>\n
Authors<\/td>\nPo-Hsiang Wang1,2,3,\u2020,*,<\/sup> Ming-Jing He1,\u2020<\/sup>, Ruiqin Yi4<\/sup>, Rehana Afrin5<\/sup>, Kun-Ti Liao2,3<\/sup>, Wen-Chi Yu1<\/sup>, Shota Nishikawa5<\/sup>, Mahendran Sithamparam6<\/sup>, Chen Chen7<\/sup>, Kosuke Fujishima5,8,9<\/sup>, Kuhan Chandru6,10,11<\/sup>, and Tony Z. Jia3,5,*<\/sup><\/td>\n<\/tr>\n
Affiliations<\/td>\n\n
    \n
  1. Graduate Institute of Environmental Engineering, National Central University, No. 300, Zhongda Rd., Zhongli District, Taoyuan 32001, Taiwan (R.O.C.)<\/li>\n
  2. Department of Chemical Engineering and Materials Engineering, National Central University, No. 300, Zhongda Rd., Zhongli District, Taoyuan 32001, Taiwan (R.O.C.)<\/li>\n
  3. Blue Marble Space Institute of Science, 600 First Avenue, Floor 1, Seattle, Washington 98104, United States<\/li>\n
  4. State Key Laboratory of Deep Earth Processes and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China<\/li>\n
  5. Earth-Life Science Institute, Institute of Future Science, Institute of Science Tokyo, 2-12-1-IE-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan<\/li>\n
  6. Space Science Centre (ANGKASA), Institute of Climate Change, National University of Malaysia, UKM Bangi, Darul Ehsan, Selangor 43650, Malaysia<\/li>\n
  7. Biofunctional Catalyst Research Team, RIKEN Center for Sustainable Resource Science (CSRS), 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan<\/li>\n
  8. School of Life Science and Technology, Institute of Science Tokyo, Yokohama, Kanagawa 226-8501, Japan<\/li>\n
  9. Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa-shi, Yokohama, Kanagawa 252-0882, Japan<\/li>\n
  10. Polymer Research Center (P.O.RCE), Faculty of Science and Technology, National University of Malaysia, Wako-shi, Selangor 43600, Malaysia<\/li>\n
  11. Institute of Physical Chemistry, CENIDE, University of Duisburg-Essen, Essen 45141, Germany<\/li>\n<\/ol>\n

    \u2020These authors contributed equally<\/td>\n<\/tr>\n

DOI<\/td>\n10.1021\/acsapm.4c03955<\/a><\/td>\n<\/tr>\n
Online published date<\/td>\n1 April 2025<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n","protected":false},"featured_media":9267,"template":"","news_events_cat":[9],"acf":[],"_links":{"self":[{"href":"https:\/\/www.elsi.jp\/wp-json\/wp\/v2\/news_events\/9415"}],"collection":[{"href":"https:\/\/www.elsi.jp\/wp-json\/wp\/v2\/news_events"}],"about":[{"href":"https:\/\/www.elsi.jp\/wp-json\/wp\/v2\/types\/news_events"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.elsi.jp\/wp-json\/wp\/v2\/media\/9267"}],"wp:attachment":[{"href":"https:\/\/www.elsi.jp\/wp-json\/wp\/v2\/media?parent=9415"}],"wp:term":[{"taxonomy":"news_events_cat","embeddable":true,"href":"https:\/\/www.elsi.jp\/wp-json\/wp\/v2\/news_events_cat?post=9415"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}