Systems Environmental Microbiology Group, The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs Lyngby, 2800, Denmark.
Microbial and Plant Biotechnology Department, Centro de Investigaciones Biológicas «Margarita Salas» (CIB-CSIC), Polymer Biotechnology Group, Madrid, 28040, Spain.
Biotechnol J. 2021 Mar;16(3):e2000165. doi: 10.1002/biot.202000165. Epub 2020 Nov 9.
Growing environmental concern sparks renewed interest in the sustainable production of (bio)materials that can replace oil-derived goods. Polyhydroxyalkanoates (PHAs) are isotactic polymers that play a critical role in the central metabolism of producer bacteria, as they act as dynamic reservoirs of carbon and reducing equivalents. PHAs continue to attract industrial attention as a starting point toward renewable, biodegradable, biocompatible, and versatile thermoplastic and elastomeric materials. Pseudomonas species have been known for long as efficient biopolymer producers, especially for medium-chain-length PHAs. The surge of synthetic biology and metabolic engineering approaches in recent years offers the possibility of exploiting the untapped potential of Pseudomonas cell factories for the production of tailored PHAs. In this article, an overview of the metabolic and regulatory circuits that rule PHA accumulation in Pseudomonas putida is provided, and approaches leading to the biosynthesis of novel polymers (e.g., PHAs including nonbiological chemical elements in their structures) are discussed. The potential of novel PHAs to disrupt existing and future market segments is closer to realization than ever before. The review is concluded by pinpointing challenges that currently hinder the wide adoption of bio-based PHAs, and strategies toward programmable polymer biosynthesis from alternative substrates in engineered P. putida strains are proposed.
日益增长的环境问题引发了人们对可持续生产（生物）材料的浓厚兴趣，这些材料可以替代石油衍生产品。聚羟基烷酸酯（PHA）是立体聚合物，在产菌的中心代谢中起着关键作用，因为它们是碳和还原当量的动态储存库。PHA 继续吸引工业界的关注，因为它们是可再生、可生物降解、生物相容和多功能热塑性弹性体材料的起点。多年来，人们一直知道假单胞菌是高效的生物聚合物生产菌，尤其是生产中链长 PHA。近年来，合成生物学和代谢工程方法的涌现，为开发假单胞菌细胞工厂的未开发潜力，生产定制化 PHA 提供了可能。本文概述了调控假单胞菌属中 PHA 积累的代谢和调控回路，并讨论了导致新型聚合物（例如，其结构中包含非生物化学元素的 PHA）生物合成的方法。新型 PHA 颠覆现有和未来市场细分领域的潜力比以往任何时候都更加接近现实。本文最后指出了当前阻碍生物基 PHA 广泛应用的挑战，并提出了在工程假单胞菌菌株中，利用替代底物进行可编程聚合物生物合成的策略。
