Ramanathan Thulasya, Ting Yen-Peng
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585, Singapore.
Chemosphere. 2016 Oct;160:54-61. doi: 10.1016/j.chemosphere.2016.06.055. Epub 2016 Jun 27.
The increasing demand for energy and the generation of solid waste have caused an alarming rise in fly ash production globally. Since heavy metals continue to be in demand for the production of materials, resource recovery from the recycling of these wastes has the potential to delay the depletion of natural ores. The use of microorganisms for the leaching of metals, in a process called bioleaching, is an eco-friendly and economical way to treat the metal-laden wastes. Bioleaching of fly ash is challenging due largely to the alkaline nature and toxic levels of heavy metals which are detrimental to microbial growth and bioleaching activity. The present work reports the isolation of indigenous bacteria from a local landfill site and their bioleaching performance [corrected]. 38 autochthonous strains of bacteria were isolated from eight samples collected and plated on five different media. 18 of the isolates showed bioleaching potential, with significant alkaline pH or fly ash tolerance. Genetic characterization of the strains revealed a dominance of Firmicutes, with Alkalibacterium sp. TRTYP6 showing highest fly ash tolerance of up to 20% w/v fly ash, and growth over a pH range 8-12.5. The organism selectively recovered about 52% Cu from the waste. To the best of our knowledge, this is the first time a study on bioleaching with extreme alkaliphiles is reported.
全球对能源需求的不断增加以及固体废物的产生导致粉煤灰产量惊人地上升。由于材料生产对重金属的需求持续存在，从这些废物的回收中进行资源回收有可能延缓天然矿石的枯竭。在一种称为生物浸出的过程中，利用微生物浸出金属是一种处理含金属废物的环保且经济的方法。粉煤灰的生物浸出具有挑战性，主要是因为其碱性性质和重金属的毒性水平，这些对微生物生长和生物浸出活性有害。目前的工作报道了从当地垃圾填埋场分离本土细菌及其生物浸出性能[已修正]。从收集的八个样品中分离出38株本地细菌菌株，并接种在五种不同的培养基上。其中18株分离物显示出生物浸出潜力，具有显著的碱性pH耐受性或粉煤灰耐受性。对这些菌株的基因表征显示厚壁菌门占主导地位，其中碱杆菌属TRTYP6对粉煤灰的耐受性最高，可达20%（w/v）粉煤灰，并且在pH值8 - 12.5的范围内生长。该微生物从废物中选择性回收了约52%的铜。据我们所知，这是首次报道关于极端嗜碱菌生物浸出的研究。
