Towards sustainability by integrated microbial degradation and closed-loop biological recycling of the copolymer poly (3-hydroxybutyrate-co-3-hydroxyvalerate) by Azohydromonas australica DSM 1124

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability Pub Date : 2025-05-08 DOI:10.1016/j.polymdegradstab.2025.111420

Sirirach Nanthachai , Beom Soo Kim , Kohsuke Honda , Suchada Chanprateep Napathorn

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引用次数: 0

Abstract

Achieving a fully closed-loop waste management system for polyhydroxyalkanoates (PHA) is a key focus for sustainable solutions. Among the one hundred forty-two PHA-producing strains tested, Azohydromonas australica DSM 1124 showed a remarkable ability to degrade poly (3-hydroxybutyrate-co-3-hydroxyvalerate, PHBV) on PHBV-suspended agar media. The effects of different carbon‒nitrogen (C/N) ratios (mol/mol) were investigated in mineral salt media (MSM) and compared with those in yeast extract peptone (YP) media. The C/N ratio of 770 yielded the greatest PHBV degradation, with 79.4 ± 4.8 % film weight loss, and subsequently resulted in 27.6 ± 2.2 % PHA content and a Y_P/S of 0.245 g-PHBV produced/g-PHBV film in a one pot process. Various techniques were employed, including differential scanning calorimetry (DSC), scanning electron microscopy (SEM), gel permeation chromatography (GPC) and X-ray diffraction (XRD). X-ray diffraction confirmed that orthorhombic α-form crystals with helical chain conformations and β-form crystals with planar zigzag conformations were significantly degraded. Biological recycling in a 10-L fermenter resulted in 70.3 ± 0.1 % PHBV film weight loss by the action of PHA depolymerase enzymes, leading to the formation of oligomers and monomers. Subsequently, A. australica DSM 1124 has assimilated and internalized these monomers as substrates for the biosynthesis of renewed PHBV, achieving a PHA content of 12.9 ± 0.1 %. This study demonstrates the potential of A. australica DSM 1124 for integrated microbial degradation and closed-loop recycling, offering a one-pot sustainable approach to mitigate PHA waste accumulation in ecosystems.

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澳大利亚偶氮单胞菌对共聚物聚（3-羟基丁酸酯-co-3-羟基戊酸酯）的综合微生物降解和闭环生物循环的可持续性研究

实现聚羟基烷酸酯（PHA）的全闭环废物管理系统是可持续解决方案的重点。在142株产生pha的菌株中，澳大利亚偶氮单胞菌DSM 1124在PHBV悬浮琼脂培养基上表现出显著的降解聚3-羟基丁酸-co-3-羟戊酸（PHBV）的能力。研究了不同碳氮比（C/N）对无机盐（MSM）培养基的影响，并与酵母膏蛋白胨（YP）培养基进行了比较。当C/N比为770时，PHBV的降解效果最好，膜重损失79.4±4.8%，PHA含量为27.6±2.2%，一锅法制备的PHBV膜YP/S为0.245 g-PHBV。采用了多种技术，包括差示扫描量热法（DSC）、扫描电镜（SEM）、凝胶渗透色谱法（GPC）和x射线衍射法（XRD）。x射线衍射证实，具有螺旋链构象的正交α-型晶体和具有平面之字形构象的β-型晶体明显退化。在10-L的发酵罐中进行生物回收，通过PHA解聚酶的作用，PHBV膜重量减少70.3±0.1%，形成低聚物和单体。随后，a . australica DSM 1124吸收并内化这些单体作为生物合成更新PHBV的底物，PHA含量达到12.9±0.1%。本研究证明了a . austrica DSM 1124在综合微生物降解和闭环回收方面的潜力，为减少PHA废物在生态系统中的积累提供了一种可持续的方法。

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来源期刊

Polymer Degradation and Stability 化学-高分子科学

CiteScore

10.10

自引率

10.20%

发文量

325

审稿时长

23 days

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.