The Affiliated High School of Peking University, Beijing, 100080, China.
Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
Biochem Biophys Res Commun. 2023 Sep 10;672:113-119. doi: 10.1016/j.bbrc.2023.06.051. Epub 2023 Jun 15.
Photosynthetic microorganisms such as cyanobacteria can convert photons into electrons, providing ideal eco-friendly materials for converting solar energy into electricity. However, the electrons are hardly transported outside the cyanobacterial cells due to the insulation feature of the cell wall/membrane. Various nanomaterials have been reported to enhance extracellular electron transfer of heterotrophic electroactive microorganisms, but its effect on intact photosynthetic microorganisms remains unclear. In this study, we investigated the effect of six different nanomaterials on the photocurrent generation of cyanobacterium Synechocystis sp. PCC 6803. Among the nanomaterials tested, titanium dioxide (TiO) nanoparticles increased the photocurrent generation of Synechocystis sp. PCC 6803 up to four-fold at the optimum concentration of 2 mg/mL. Transmission electron microscopy and scanning electron microscopy showed that TiO bound to cyanobacterial cells and likely penetrated inside of cell membrane. Photochemical analyses for photosystems showed that TiO blocked the electrons transfer downstream in PS I, implying a possible extracellular electron pathway mediated by TiO. This study provides an alternative approach for enhancing the photocurrent generation of cyanobacteria, showing the potential of photosynthetic-nanomaterial hybrids.
光合微生物，如蓝细菌，可以将光子转化为电子，为将太阳能转化为电能提供理想的环保材料。然而，由于细胞壁/膜的绝缘特性，电子很难在蓝细菌细胞外传输。已经有各种纳米材料被报道可以增强异养电活性微生物的细胞外电子转移，但它对完整光合微生物的影响尚不清楚。在这项研究中，我们研究了六种不同纳米材料对集胞藻 PCC 6803 光合作用电流产生的影响。在所测试的纳米材料中，二氧化钛（TiO）纳米颗粒在最佳浓度 2mg/mL 时将集胞藻 PCC 6803 的光合作用电流增加了四倍。透射电子显微镜和扫描电子显微镜显示，TiO 与蓝细菌细胞结合，并可能穿透细胞膜内部。对光系统的光化学分析表明，TiO 阻止了 PS I 下游的电子转移，这意味着可能存在由 TiO 介导的细胞外电子途径。这项研究为增强蓝细菌的光合作用电流提供了一种替代方法，展示了光合-纳米材料杂种的潜力。
