Polyhydroxyalkanoates (PHAs) are microbial polyesters attracting great attention while further functionalisation could widen their applicability. Various Escherichia coli based production systems using the PHA biosynthetic operon from Bacillus cereus 6E/2 were designed to enhance the accumulation of PHAs with high medium chain length moieties. Media optimization and system engineering were applied, yielding the production of PHAs up to 260 mg L⁻¹. Polymer characterization revealed a low grade of crystallinity and remarkable hydrophobic features. For further functionalization, a novel enzyme based strategy was developed. Lipase B from Candida antarctica (CaLB) was used to catalyze the terminal coupling of PHAs with: (i) dimethyl itaconate (DMI) in order to introduce reactive side chain vinyl moieties for the easy coupling of functional molecules and/or (ii) biocompatible polyethylene glycol (PEG) to tune polymer hydrophilicity. The functionalized DMI–PHA, PEG–PHA and PEG–DMI–PHA polymers obtained and characterised by NMR, GPC, FT-IR, and WCA in this study open new perspectives on the use of PHAs as biodegradable and biocompatible materials of choice for biomedical applications.

中文翻译：

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酶促生产可点击的和聚乙二醇化的重组聚羟基链烷酸酯

聚羟基链烷酸酯（PHA）是引起人们极大关注的微生物聚酯，而进一步的功能化可以扩大其适用性。设计了使用来自蜡状芽胞杆菌6E / 2的PHA生物合成操纵子的各种基于大肠杆菌的生产系统，以增强具有高中链长度部分的PHAs的积累。应用了媒体优化和系统工程设计，产生了高达260 mg L ^-1的PHA 。聚合物表征显示出较低的结晶度和显着的疏水性。为了进一步的功能化，开发了一种新颖的基于酶的策略。南极假丝酵母的脂肪酶B（CaLB）用于催化PHA与以下物质的末端偶联：（i）衣康酸二甲酯（DMI），以引入反应性侧链乙烯基部分，以易于偶联功能分子和/或（ii）生物相容性聚乙二醇（PEG）调节聚合物的亲水性。通过NMR，GPC，FT-IR和WCA表征并获得的功能化DMI–PHA，PEG–PHA和PEG–DMI–PHA聚合物在本研究中开辟了新的前景，将PHA用作生物医学的可生物降解和生物相容性材料的选择应用程序。