Department of Civil Engineering, School of Engineering, Kyushu University, 744 Motooka, Nishi-Ku, Fukuoka 819-0395, Japan.
Environ Geochem Health. 2013 Aug;35(4):431-8. doi: 10.1007/s10653-012-9505-8. Epub 2012 Dec 5.
Boron is an essential micronutrient for plants, but can above certain concentrations be toxic to living organisms. A major environmental concern is the removal of boron from contaminated water and fly ash. For this purpose, the samples were collected from a fly ash dumping site, Nagasaki prefecture, Japan. The chemical characteristics and heavy metal concentration of the samples were performed by X-ray fluorescent analysis and leaching test. For bacterial analysis, samples were collected in sterile plastic sheets and isolation was carried out by serial dilution method. The boron tolerant isolates that showed values of maximum inhibitory concentration toward boron ranging from 100 to 260 mM level were screened. Based on 16S rRNA sequencing and phylogenetic analysis, the isolates were most closely related to the genera Bacillus, Lysinibacillus, Microbacterium and Ralstonia. The boron tolerance of these strains was also associated with resistant to several heavy metals, such as As (III), Cr (VI), Cd, Cu, Pb, Ni, Se (III) and Zn. Indeed, these strains were arsenic oxidizing bacteria confirmed by silver nitrate test. These strains exhibited their salt resistances ranging from 4 to 15 % were determined in Trypticase soy agar medium. The boron tolerant strains were capable of removing 0.1-2.0 and 2.7-3.7 mg l(-1) boron from the medium and fly ash at 168 h. Thus, we have successfully identified the boron tolerant and removal bacteria from a fly ash dumping site for boron remediation.
硼是植物必需的微量元素，但在一定浓度以上对生物体可能有毒。一个主要的环境问题是从受污染的水中和飞灰中去除硼。为此，从日本长崎县的一个飞灰倾倒场收集了样品。通过 X 射线荧光分析和浸出试验对样品的化学特性和重金属浓度进行了分析。为了进行细菌分析，在无菌塑料片上采集了样品，并通过连续稀释法进行了分离。筛选出对硼的最大抑制浓度值在 100 至 260 mM 之间的硼耐受分离株。基于 16S rRNA 测序和系统发育分析，分离株与芽孢杆菌属、赖氨酸芽孢杆菌属、微杆菌属和罗尔斯顿氏菌属最为密切相关。这些菌株的硼耐受性也与对几种重金属的抗性有关，如砷（III）、铬（VI）、镉、铜、铅、镍、硒（III）和锌。事实上，这些菌株是通过硝酸银试验确认的砷氧化菌。这些菌株在胰蛋白酶大豆琼脂培养基中表现出 4%至 15%的盐度抗性。在 168 小时内，耐硼菌株能够从培养基和飞灰中去除 0.1-2.0 和 2.7-3.7mg·l（-1）的硼。因此，我们已经成功地从飞灰倾倒场中鉴定出了耐硼和去除硼的细菌，用于硼的修复。
