Institute of Science and Technology (ICT), Federal University of São Paulo (UNIFESP), São José dos Campos, SP, 12231-280, Brazil.
Department of Chemical and Food Engineering (EQA), Federal University of Santa Catarina (UFSC), Florianópolis, SC, 88040-900, Brazil.
Appl Microbiol Biotechnol. 2019 Sep;103(17):7231-7240. doi: 10.1007/s00253-019-10001-2. Epub 2019 Jul 10.
Sulfur minerals originating from coal mining represent an important environmental problem. Turning these wastes into value-added by-products can be an interesting alternative. Biotransformation of coal tailings into iron-containing nanoparticles using Rhodococcus erythropolis ATCC 4277 free cells was studied. The influence of culture conditions (stirring rate, biomass concentration, and coal tailings ratio) in the particle size was investigated using a 2 full factorial design. Statistical analysis revealed that higher concentrations of biomass produced larger sized particles. Conversely, a more intense stirring rate of the culture medium and a higher coal tailings ratio (% w/w) led to the synthesis of smaller particles. Thus, the culture conditions that produced smaller particles (< 50 nm) were 0.5 abs of normalized biomass concentration, 150 rpm of stirring rate, and 2.5% w/w of coal tailings ratio. Composition analyses showed that the biosynthesized nanoparticles are formed by iron sulfate. Conversion ratio of the coal tailings into iron-containing nanoparticles reached 19%. The proposed biosynthesis process, using R. erythropolis ATCC 4277 free cells, seems to be a new and environmentally friendly alternative for sulfur minerals reuse.
源自煤矿开采的硫矿是一个重要的环境问题。将这些废物转化为增值的副产品是一个有趣的选择。使用红球菌（Rhodococcus erythropolis）ATCC 4277 游离细胞将煤矸石生物转化为含铁纳米颗粒进行了研究。使用 2 全因子设计研究了培养条件（搅拌速度、生物量浓度和煤矸石比例）对粒径的影响。统计分析表明，较高的生物质浓度会产生较大粒径的颗粒。相反，培养基更剧烈的搅拌速度和更高的煤矸石比例（%w/w）会导致较小颗粒的合成。因此，产生较小颗粒（<50nm）的培养条件为归一化生物量浓度为 0.5abs、搅拌速度为 150rpm 和煤矸石比例为 2.5%w/w。组成分析表明，生物合成的纳米颗粒由硫酸铁组成。煤矸石转化为含铁纳米颗粒的转化率达到 19%。使用红球菌（Rhodococcus erythropolis）ATCC 4277 游离细胞的这种生物合成方法似乎是一种新的、环保的硫矿再利用替代方法。
