El-Sharkawy Reyad M, Khairy Mohamed, Zaki Magdi E A, Al-Tabbakh Al-Shaimaa M
Botany and Microbiology Department, Faculty of Science, Benha University, Benha, 13511, Egypt.
Chemistry Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), 11623, Riyadh, Saudi Arabia.
Microb Cell Fact. 2025 Feb 21;24(1):44. doi: 10.1186/s12934-025-02648-6.
Sustainable biosynthesis of metal oxide nanoparticles using an eco-friendly approach is a growing research area owing to their promising environmental and biomedical applications. This work aims to biosynthesize and characterize magnesium oxide nanoparticles (MgONPS@Aj) for possible application in dye biosorption and antibacterial activity. For the first time, MgONPS@Aj was successfully synthesized by harnessing exometabolites of Aspergillus japonicus. Various parameters were statistically optimized to maximize the production of MgONPS@Aj using Plackett Burman's design and central composite design. The analysis of variance (ANOVA) revealed that pH was the most significant variable, affecting the bioproduction process followed by biomass quantity and Mg precursor concentration. The suggested model (quadratic) was greatly significant and acceptable due to the nonsignificant lack of fit (15.10), and P-value (0.001). The optimized nanoparticles were characterized using X-ray powder diffraction, Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscope (TEM), and Scanning electron microscopy. A high biosorption capacity (204.08 mg/g) of reactive black 5 dye was achieved within 40 min using a 5 mg biosorbent dose (MgONPS@Aj), 100 mg/l initial dye concentration, and pH 6.0. The biosorption process followed a pseudo-second-order (R of 0.9842) and Langmuir isotherm (R of 0.9422) models with a dimensionless separation factor (R) of 8 × 10, hinting favorable and effective biosorption of dye molecules. A biosorption capacity of 81.97 mg/g after five successive cycles hints that the nanomaterial is suitable for several time utilization. Biogenic MgONPS@Aj displayed dramatic concentration-dependent antibacterial activity with the largest inhibition zones for P. aeruginosa (24.1 ± 0.8 mm, MIC: 3.125 µg/ml), followed by E. coli (22.3 ± 0.7 mm, MIC 6.25), B. subtilis (14.7 ± 0.4 mm, MIC: 12.5 µg/ml) and S. aureus (19.2 ± 0.6 mm, MIC: 6.25 µg/ml). The antibacterial activity was further interpreted using molecular simulation analysis. The lowest binding affinity was determined between MgONPS@Aj and target bacterial proteins (chloramphenicol acetyltransferase E. coli, and S. aureus MurE). The ligand (MgONPS@Aj) can bind to the active site's residues (Tyr and SER), indicating a possible antibacterial mechanism. This study recommends MgONPS@Aj as an eco-friendly, and reusable alternative to traditional anionic dye sorbents and a uniquely promising candidate for antimicrobial applications.
使用环保方法可持续生物合成金属氧化物纳米颗粒是一个不断发展的研究领域，因为它们在环境和生物医学应用方面颇具前景。这项工作旨在生物合成和表征氧化镁纳米颗粒（MgONPS@Aj），以探讨其在染料生物吸附和抗菌活性方面的潜在应用。首次利用日本曲霉的胞外代谢产物成功合成了MgONPS@Aj。采用Plackett Burman设计和中心复合设计对各种参数进行了统计优化，以最大限度地提高MgONPS@Aj的产量。方差分析（ANOVA）表明，pH是影响生物生产过程的最显著变量，其次是生物量和镁前体浓度。所建议的模型（二次模型）非常显著且可接受，因为失拟项不显著（15.10）且P值为0.001。使用X射线粉末衍射、傅里叶变换红外（FTIR）光谱、透射电子显微镜（TEM）和扫描电子显微镜对优化后的纳米颗粒进行了表征。使用5毫克生物吸附剂剂量（MgONPS@Aj）、100毫克/升初始染料浓度和pH 6.0，在40分钟内实现了活性黑5染料的高生物吸附容量（204.08毫克/克）。生物吸附过程遵循准二级动力学模型（R为0.9842）和Langmuir等温线模型（R为0.9422），无量纲分离因子（R）为8×10，表明染料分子的生物吸附是有利且有效的。连续五个循环后生物吸附容量为81.97毫克/克，这表明该纳米材料适合多次使用。生物合成的MgONPS@Aj表现出显著的浓度依赖性抗菌活性，对铜绿假单胞菌的抑菌圈最大（24.1±0.8毫米，MIC：3.125微克/毫升），其次是大肠杆菌（22.3±0.7毫米，MIC 6.25）、枯草芽孢杆菌（14.7±0.4毫米，MIC：12.5微克/毫升）和金黄色葡萄球菌（19.2±0.6毫米，MIC：6.25微克/毫升）。使用分子模拟分析进一步解释了抗菌活性。确定MgONPS@Aj与目标细菌蛋白（大肠杆菌的氯霉素乙酰转移酶和金黄色葡萄球菌的MurE）之间的结合亲和力最低。配体（MgONPS@Aj）可以与活性位点的残基（酪氨酸和丝氨酸）结合，表明可能存在抗菌机制。本研究推荐MgONPS@Aj作为一种环保且可重复使用的传统阴离子染料吸附剂替代品，以及一种极具前景的抗菌应用候选材料。
