Synthesis of High-Molecular-Weight Polyhydroxyalkanoates by Marine Photosynthetic Purple Bacteria.
Synthesis of High-Molecular-Weight Polyhydroxyalkanoates by Marine Photosynthetic Purple Bacteria.
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DOI：
10.1371/journal.pone.0160981
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Numata K
中科院分区：
文献类型：
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作者：
Higuchi-Takeuchi M;Morisaki K;Toyooka K;Numata K
聚羟基链烷酸酯 (PHA) 是一种生物聚酯/生物塑料，由多种微生物产生，用于储存碳并增加还原氧化还原电位。光合细菌利用光能将二氧化碳转化为有机化合物，并积累 PHA。我们分析了 3 种紫色硫细菌和 9 种紫色非硫细菌菌株合成的 PHA。这12株紫色细菌在含有乙酸盐和/或碳酸氢钠作为碳源的限氮培养基中培养。紫硫细菌中 PHA 的产生是由氮限制条件诱导的。紫色非硫细菌即使在正常生长条件下也能积累PHA，并且3个菌株的PHA产量在限氮条件下得到增强。凝胶渗透色谱分析表明，5 种光合紫色细菌合成了高分子量 PHA，可用于工业应用。定量逆转录聚合酶链反应分析表明，在限氮条件下，phaC 和 PhaZ 基因的 mRNA 水平较低，从而产生高分子量的 PHA。我们的结论是，所有 12 种测试菌株都能够在一定程度上合成 PHA，并且我们鉴定出 5 种能够积累高分子量 PHA 分子的光合紫色细菌。此外，光合紫色细菌在补充有醋酸盐的海水中培养时合成PHA。本研究中表征的光合紫色细菌菌株应该可用作利用丰富的海洋资源和二氧化碳进行大规模 PHA 生产的宿主微生物。
Polyhydroxyalkanoate (PHA) is a biopolyester/bioplastic that is produced by a variety of microorganisms to store carbon and increase reducing redox potential. Photosynthetic bacteria convert carbon dioxide into organic compounds using light energy and are known to accumulate PHA. We analyzed PHAs synthesized by 3 purple sulfur bacteria and 9 purple non-sulfur bacteria strains. These 12 purple bacteria were cultured in nitrogen-limited medium containing acetate and/or sodium bicarbonate as carbon sources. PHA production in the purple sulfur bacteria was induced by nitrogen-limited conditions. Purple non-sulfur bacteria accumulated PHA even under normal growth conditions, and PHA production in 3 strains was enhanced by nitrogen-limited conditions. Gel permeation chromatography analysis revealed that 5 photosynthetic purple bacteria synthesized high-molecular-weight PHAs, which are useful for industrial applications. Quantitative reverse transcription polymerase chain reaction analysis revealed that mRNA levels of phaC and PhaZ genes were low under nitrogen-limited conditions, resulting in production of high-molecular-weight PHAs. We conclude that all 12 tested strains are able to synthesize PHA to some degree, and we identify 5 photosynthetic purple bacteria that accumulate high-molecular-weight PHA molecules. Furthermore, the photosynthetic purple bacteria synthesized PHA when they were cultured in seawater supplemented with acetate. The photosynthetic purple bacteria strains characterized in this study should be useful as host microorganisms for large-scale PHA production utilizing abundant marine resources and carbon dioxide.