Faculty of Chemistry, Brno University of Technology, Purkynova 118, 612 00, Brno, Czech Republic.
University for Natural Resources and Life Sciences, IFA-Tulln, Konrad Lorenz Str. 20, 3430, Tulln, Austria.
Appl Microbiol Biotechnol. 2020 Jun;104(11):4795-4810. doi: 10.1007/s00253-020-10568-1. Epub 2020 Apr 17.
Polyhydroxyalkanoates (PHA), polyesters accumulated by numerous prokaryotes in the form of intracellular granules, have been for decades considered being predominantly storage molecules. However, numerous recent discoveries revealed and emphasized their complex biological role for microbial cells. Most of all, it was repeatedly reported and confirmed that the presence of PHA granules in prokaryotic cells enhances stress resistance and robustness of microbes against various environmental stress factors such as high or low temperature, freezing, oxidative, and osmotic pressure. It seems that protective mechanisms of PHA granules are associated with their extraordinary architecture and biophysical properties as well as with the complex and deeply interconnected nature of PHA metabolism. Therefore, this review aims at describing novel and unexpected properties of PHA granules with respect to their contribution to stress tolerance of various prokaryotes including common mesophilic heterotrophic bacteria, but also extremophiles or photo-autotrophic cyanobacteria. KEY POINTS: • PHA granules present in bacterial cells reveal unique properties and functions. • PHA enhances stress robustness of bacterial cells.
聚羟基烷酸酯（PHA）是许多原核生物以细胞内颗粒的形式积累的聚酯，几十年来一直被认为主要是储存分子。然而，最近的许多发现揭示并强调了它们对微生物细胞的复杂生物学作用。最重要的是，人们反复报道并证实，原核细胞中 PHA 颗粒的存在增强了微生物对各种环境胁迫因素的抗逆性和鲁棒性，如高温或低温、冷冻、氧化和渗透压。PHA 颗粒的保护机制似乎与其特殊的结构和生物物理特性以及 PHA 代谢的复杂和深度相互关联的性质有关。因此，本综述旨在描述 PHA 颗粒在各种原核生物（包括常见的嗜中性异养细菌）的耐受力方面的新的和意外的特性，以及极端微生物或光自养蓝细菌。关键点：
存在于细菌细胞中的 PHA 颗粒具有独特的性质和功能。
PHA 增强了细菌细胞的抗应激能力。
