{"title":"非质子聚醚诱导的聚羟基烷酸酯分子量的降低为链转移剂的作用机制提供了新的见解","authors":"Seiya Tanaka , Hiroshi Kikukawa , Hirotsugu Nakai , Shuzo Arai , Ayaka Kajikawa , Shin-ichi Hachisuka , Ken’ichiro Matsumoto","doi":"10.1016/j.polymdegradstab.2025.111656","DOIUrl":null,"url":null,"abstract":"<div><div>Some alcohols, such as diethylene glycol (DEG), bound to the polymer chain ends during polyhydroxyalkanoate (PHA) biosynthesis, are called chain-transfer (CT) agents. Moreover, the presence of CT agents in PHA biosynthesis decreases molecular weight of PHA. This study investigated whether the aprotic polyethers, diethylene glycol dimethyl ether (DGDM) and triethylene glycol dimethyl ether (TGDM), which are structurally similar to DEG, can decrease the molecular weight of PHA. Poly(3-hydroxybutyrate) [P(3HB)] was synthesized using engineered <em>Escherichia coli</em> expressing PHA synthase PhaC<sub>AR</sub> (class I) or PhaC1<sub>Ps</sub>STQK (class II) and a monomer-supplying enzyme grown on medium containing 3HB, and DEG, DGDM, or TGDM. DGDM and TGDM decreased the molecular weight of P(3HB) synthesized using PhaC<sub>AR</sub>. The aprotic polyethers were not detected from the polymers, indicating that they did not act as CT agents. Immunoblotting analysis revealed that the addition of the aprotic polyethers and DEG did not alter PhaC<sub>AR</sub> expression. Moreover, the <em>in vitro</em> assay exhibited no apparent effect of PhaC<sub>AR</sub> on polymerization activity. However, the decrease in the molecular weight by aprotic polyethers was not observed for PhaC1<sub>Ps</sub>STQK, indicating that the effect of aprotic polyethers depends on PhaC class. In conclusion, although the aprotic polyethers decrease the molecular weight of PHA, further studies are necessary to understand the underlying mechanisms different from typical CT reaction.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"242 ","pages":"Article 111656"},"PeriodicalIF":7.4000,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Aprotic polyether-induced decrease in the molecular weight of polyhydroxyalkanoate provides insights into the mechanism of action of chain-transfer agents\",\"authors\":\"Seiya Tanaka , Hiroshi Kikukawa , Hirotsugu Nakai , Shuzo Arai , Ayaka Kajikawa , Shin-ichi Hachisuka , Ken’ichiro Matsumoto\",\"doi\":\"10.1016/j.polymdegradstab.2025.111656\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Some alcohols, such as diethylene glycol (DEG), bound to the polymer chain ends during polyhydroxyalkanoate (PHA) biosynthesis, are called chain-transfer (CT) agents. Moreover, the presence of CT agents in PHA biosynthesis decreases molecular weight of PHA. This study investigated whether the aprotic polyethers, diethylene glycol dimethyl ether (DGDM) and triethylene glycol dimethyl ether (TGDM), which are structurally similar to DEG, can decrease the molecular weight of PHA. Poly(3-hydroxybutyrate) [P(3HB)] was synthesized using engineered <em>Escherichia coli</em> expressing PHA synthase PhaC<sub>AR</sub> (class I) or PhaC1<sub>Ps</sub>STQK (class II) and a monomer-supplying enzyme grown on medium containing 3HB, and DEG, DGDM, or TGDM. DGDM and TGDM decreased the molecular weight of P(3HB) synthesized using PhaC<sub>AR</sub>. The aprotic polyethers were not detected from the polymers, indicating that they did not act as CT agents. Immunoblotting analysis revealed that the addition of the aprotic polyethers and DEG did not alter PhaC<sub>AR</sub> expression. Moreover, the <em>in vitro</em> assay exhibited no apparent effect of PhaC<sub>AR</sub> on polymerization activity. However, the decrease in the molecular weight by aprotic polyethers was not observed for PhaC1<sub>Ps</sub>STQK, indicating that the effect of aprotic polyethers depends on PhaC class. In conclusion, although the aprotic polyethers decrease the molecular weight of PHA, further studies are necessary to understand the underlying mechanisms different from typical CT reaction.</div></div>\",\"PeriodicalId\":406,\"journal\":{\"name\":\"Polymer Degradation and Stability\",\"volume\":\"242 \",\"pages\":\"Article 111656\"},\"PeriodicalIF\":7.4000,\"publicationDate\":\"2025-09-06\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Polymer Degradation and Stability\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0141391025004859\",\"RegionNum\":2,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"POLYMER SCIENCE\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Polymer Degradation and Stability","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0141391025004859","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"POLYMER SCIENCE","Score":null,"Total":0}
Aprotic polyether-induced decrease in the molecular weight of polyhydroxyalkanoate provides insights into the mechanism of action of chain-transfer agents
Some alcohols, such as diethylene glycol (DEG), bound to the polymer chain ends during polyhydroxyalkanoate (PHA) biosynthesis, are called chain-transfer (CT) agents. Moreover, the presence of CT agents in PHA biosynthesis decreases molecular weight of PHA. This study investigated whether the aprotic polyethers, diethylene glycol dimethyl ether (DGDM) and triethylene glycol dimethyl ether (TGDM), which are structurally similar to DEG, can decrease the molecular weight of PHA. Poly(3-hydroxybutyrate) [P(3HB)] was synthesized using engineered Escherichia coli expressing PHA synthase PhaCAR (class I) or PhaC1PsSTQK (class II) and a monomer-supplying enzyme grown on medium containing 3HB, and DEG, DGDM, or TGDM. DGDM and TGDM decreased the molecular weight of P(3HB) synthesized using PhaCAR. The aprotic polyethers were not detected from the polymers, indicating that they did not act as CT agents. Immunoblotting analysis revealed that the addition of the aprotic polyethers and DEG did not alter PhaCAR expression. Moreover, the in vitro assay exhibited no apparent effect of PhaCAR on polymerization activity. However, the decrease in the molecular weight by aprotic polyethers was not observed for PhaC1PsSTQK, indicating that the effect of aprotic polyethers depends on PhaC class. In conclusion, although the aprotic polyethers decrease the molecular weight of PHA, further studies are necessary to understand the underlying mechanisms different from typical CT reaction.
期刊介绍:
Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology.
Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal.
However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.