背景:随着人口的迅速增加,城市化和工业化,环境暴露于充满广谱毒性的废水的不受控制的排放,持久性和远距离传播人为化合物,其中重金属。这使我们的生态系统处于生态急剧恶化的边缘或危险之中,最终对公众健康产生不利影响。因此,这项研究采用了海洋真菌菌株Rhodotorulasp。MZ312369使用有前途的碳酸钙(CaCO3)生物沉淀技术修复Zn2和Cr6,第一次。
结果:最初,采用Plackett-Burman设计,然后进行中央复合设计,以优化碳酸酐酶(CA)。与基础条件相比,它成功地将其活性提高到154U/mL,增加了1.8倍。我们的生物工厂在修复Zn2+(50ppm)和Cr6+(400ppm)的潜力通过几个参数,包括微生物计数的动态研究进行监测,CA活动,CaCO3重量,pH值波动,随着Zn2+和Cr6+改变Ca2+的可溶性浓度。结果表明,9.23×107±2.1×106CFU/mL和10.88×107±2.5×106CFU/mL的细胞在132h时表现出最大的CA活性,分别为124.84±1.24和140±2.5U/mLZn2和Cr6,分别。同时,随着pH值增加到9.5±0.2,在168小时时观察到两种金属的完全去除;Zn2+和Cr6+修复实验记录的Ca2+去除百分比为78.99%和85.06%,分别。Further,身份,元素组成,还通过矿物学分析检查了生物介导的沉淀物的功能结构和形态。EDX模式显示了C的典型信号,O和Ca伴随有Zn2+和Cr6+峰。SEM显微照片描绘了纺锤体,球形和立方体形状的生物材料,尺寸范围为1.3±0.5-23.7±3.1µm。同时,XRD示意图揭示了补救样品中球腾石相的普遍性。此外,FTIR谱图强调了球文石光谱峰和金属波数的存在。
结论:CA酶介导的Zn2+和Cr6+通过微生物生物矿化过程固定和包封在强力球aterite捕集器内,这被认为是减轻重金属毒性并限制其在土壤和废水中流动性的替代生态解决方案。
BACKGROUND: With rapid elevation in population, urbanization and industrialization, the environment is exposed to uncontrolled discharge of effluents filled with broad-spectrum toxicity, persistence and long-distance transmission anthropogenic compounds, among them heavy metals. That put our ecosystem on the verge or at a stake of drastic ecological deterioration, which eventually adversely influence on public health. Therefore, this study employed marine fungal strain Rhodotorula sp. MZ312369 for Zn2+ and Cr6+ remediation using the promising calcium carbonate (CaCO3) bioprecipitation technique, for the first time.
RESULTS: Initially, Plackett-Burman design followed by central composite design were applied to optimize carbonic anhydrase enzyme (CA), which succeeded in enhancing its activity to 154 U/mL with 1.8-fold increase comparing to the basal conditions. The potentiality of our biofactory in remediating Zn2+ (50 ppm) and Cr6+ (400 ppm) was monitored through dynamic study of several parameters including microbial count, CA activity, CaCO3 weight, pH fluctuation, changing the soluble concentrations of Ca2+ along with Zn2+ and Cr6+. The results revealed that 9.23 × 107 ± 2.1 × 106 CFU/mL and 10.88 × 107 ± 2.5 × 106 CFU/mL of cells exhibited their maximum CA activity by 124.84 ± 1.24 and 140 ± 2.5 U/mL at 132 h for Zn2+ and Cr6+, respectively. Simultaneously, with pH increase to 9.5 ± 0.2, a complete removal for both metals was observed at 168 h; Ca2+ removal percentages recorded 78.99% and 85.06% for Zn2+ and Cr6+ remediating experiments, respectively. Further, the identity, elemental composition, functional structure and morphology of bioremediated precipitates were also examined via mineralogical analysis. EDX pattern showed the typical signals of C, O and Ca accompanying with Zn2+ and Cr6+ peaks. SEM micrographs depicted spindle, spherical and cubic shape bioliths with size range of 1.3 ± 0.5-23.7 ± 3.1 µm. Meanwhile, XRD difractigrams unveiled the prevalence of vaterite phase in remediated samples. Besides, FTIR profiles emphasized the presence of vaterite spectral peaks along with metals wavenumbers.
CONCLUSIONS: CA enzyme mediated Zn2+ and Cr6+ immobilization and encapsulation inside potent vaterite trap through microbial biomineralization process, which deemed as surrogate ecofriendly solution to mitigate heavy metals toxicity and restrict their mobility in soil and wastewater.