Graduate School of Advanced Science and Technology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa, 923-1292, Japan.
Chem Rec. 2018 Jul;18(7-8):1167-1177. doi: 10.1002/tcr.201700074. Epub 2018 Mar 15.
Cyanobacteria are regarded as very eco-friendly microreactors for the production of various biomolecules such as polysaccharides by fixing not only carbon but also nitrogen in water. Cyanobacterial polysaccharides having various functional groups such as hydroxyls, carboxyls, sulfates, etc. have the ability to interact with metals or inorganics, to create bionanocomposites. Sacran, a supergiant cyanobacterial anionic polysaccharide extracted from the extracellular matrix of Aphanothece sacrum which is mass-cultivated in freshwater, is mainly used to create functional bionanocomposites. Gel-type bionanocomposites of sacran with various metal cations are formed and showed photoresponsive functions. Metal recovery is performed from the sacran bionanocomposite gels. Sacran chains are complexed with multi-wall carbon nanotubes (MWCNT) to give viscose dispersion from which MWCNT bionanocomposites can be collected by electrophoresis. The MWCNT/sacran dispersion retains the capability of adsorbing various metal ions to form hardened hydrogel beads. Finally, natural inorganic sepiolite can be used for sacran bionanocomposites which show an efficient neodymium ion adsorption ability. Thus, cyanobacterial polysaccharides are useful for preparing eco-friendly and functional bionanocomposites with various hard materials.
蓝藻被认为是非常环保的微反应器，可通过固定水中的碳和氮来生产各种生物分子，如多糖。蓝藻多糖具有各种官能团，如羟基、羧基、硫酸根等，具有与金属或无机物相互作用的能力，从而创造出生物纳米复合材料。从淡水大规模培养的 Aphanothece sacrum 细胞外基质中提取的超大蓝藻阴离子多糖 sacran 主要用于制造功能性生物纳米复合材料。形成了 sacran 与各种金属阳离子的凝胶型生物纳米复合材料，并表现出光响应功能。从 sacran 生物纳米复合材料凝胶中回收金属。将 sacran 链与多壁碳纳米管 (MWCNT) 络合，从其中通过电泳收集 MWCNT 生物纳米复合材料。MWCNT/sacran 分散体保留了吸附各种金属离子形成硬化水凝胶珠的能力。最后，可以使用天然无机海泡石来制备 sacran 生物纳米复合材料，其具有高效的钕离子吸附能力。因此，蓝藻多糖可用于制备具有各种硬材料的环保型和功能性生物纳米复合材料。
