Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, 21934, New Borg El-Arab City, Alexandria, Egypt.
Environ Sci Pollut Res Int. 2019 Aug;26(23):23661-23678. doi: 10.1007/s11356-019-05479-2. Epub 2019 Jun 15.
Disinfection of water and wastewater strongly contributes to solving the problem of water shortage in arid/semi-arid areas; cheap and ecofriendly approaches have to be used to meet water quality standards. In the present study, a green synthesis of iron nanoparticles (INPs) under aerobic and anaerobic conditions via nitrate reductases (NAP/NAR) enzymes produced by Proteus mirabilis strain 10B were employed for this target. The biosynthesized INPs were characterized; UV-Vis spectroscopy revealed surface plasmon resonance at 410 (aerobic) and 265 nm (anaerobic). XRD indicated crystalline magnetite ((MNPs) aerobically synthesized) and zerovalent INPs (ZVINPs anaerobically synthesized). EDX demonstrated strong iron signal with atomic percentages 73.3% (MNPs) and 61.7% (ZVINPs). TEM micrographs illustrated tiny, spherical, periplasmic MNPs (1.44-1.92 nm) and cytoplasmic ZVINPs with 11.7-60.8 nm. Zeta potential recorded - 31.8 mV (ZVINPs) and - 66.4 mV (MNPs) affirming colloidal stability. Moreover, the disinfection power of INPs was evaluated for standards organisms and real water (fresh, sea and salt mine) and wastewater (municipal, agricultural and industrial) samples. The results reported that INPs displayed higher antagonistic effect than iron precursor, 700 and 850 μg/mL of MNPs and ZVINPs, respectively, was sufficient to show a drastic algicidal effect on algal growth. Both types of INPs demonstrated obvious dose-dependent antibiofilm efficiency. Due to their smaller size, MNPs were more efficient than ZVINPs at the suppression of microbial growth in all examined water samples. Overall, MNPs showed superior antagonistic activity, which promotes their exploitation in enhancing water/wastewater quality.
水和废水的消毒对于解决干旱/半干旱地区的水资源短缺问题有很大的帮助；必须采用廉价且环保的方法来达到水质标准。在本研究中，采用通过奇异变形杆菌 10B 产生的硝酸盐还原酶（NAP/NAR）酶在有氧和厌氧条件下绿色合成的铁纳米颗粒（INPs）来实现这一目标。对生物合成的 INPs 进行了表征；紫外可见光谱显示表面等离子体共振在 410nm（有氧）和 265nm（厌氧）处。XRD 表明有氧合成的结晶磁铁矿（MNPs）和零价 INPs（ZVINPs）。EDX 证明了具有 73.3%（MNPs）和 61.7%（ZVINPs）原子百分比的强铁信号。TEM 显微照片说明了微小的、球形的、周质 MNPs（1.44-1.92nm）和细胞质 ZVINPs，直径为 11.7-60.8nm。记录的 Zeta 电位为-31.8mV（ZVINPs）和-66.4mV（MNPs），证实胶体稳定性。此外，还评估了 INPs 对标准生物和实际水（淡水、海水和盐矿水）和废水（城市、农业和工业）样品的消毒能力。结果表明，INPs 的拮抗作用高于铁前体，700 和 850μg/mL 的 MNPs 和 ZVINPs 分别足以对藻类生长产生剧烈的杀藻作用。两种类型的 INPs 都表现出明显的剂量依赖性抗生物膜效率。由于 MNPs 的尺寸较小，因此在所有检测水样中，MNPs 比 ZVINPs 更有效地抑制微生物生长。总的来说，MNPs 表现出优越的拮抗活性，这促进了它们在提高水质/废水质量方面的应用。
