"Gheorghe Asachi" Technical University of Iasi, Cristofor Simionescu Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 73 Prof. Dimitrie Mangeron Blvd., 700050, Iasi, Romania.
"Gheorghe Asachi" Technical University of Iasi, Cristofor Simionescu Faculty of Chemical Engineering and Environmental Protection, Department of Environmental Engineering and Management, 73 Prof. Dimitrie Mangeron Blvd., 700050, Iasi, Romania; "Gheorghe Asachi" Technical University of Iasi, Faculty of Hydrotechnical Engineering, Geodesy and Environmental Engineering, Department of Hydrology and Environmental Protection, 65 Prof. Dimitrie Mangeron Blvd., 700050, Iasi, Romania.
N Biotechnol. 2020 May 25;56:130-139. doi: 10.1016/j.nbt.2020.01.003. Epub 2020 Jan 13.
In situ bioremediation processes are important for control of pollution and clean-up of contaminated sites. The study and implementation of such processes can be designed through investigations on natural mechanisms of absorption, biotransformation, bioaccumulation and toxicity of pollutants in plants and microorganisms. Here, the phytotoxic effects of Cr(VI) and Cd(II) on seed germination and plant growth of Lepidium sativum have been examined at various concentrations (30-300 mg/L) in single ion solutions. The studies also addressed the ecotoxicity of metal ions on Azotobacter chroococcum and Pichia sp. isolated from soil. Microbial growth was estimated by weighing the dry biomass and determining the enzymatic activities of dehydrogenase and catalase. The results showed that Cr(VI) and Cd(II) can inhibit L. sativum seed germination and root development, depending on the metal ion and its concentration. The phytotoxic effect of heavy metals was also confirmed by the reduced amounts of dried biomass. Toxicity assays demonstrated the adverse effect of Cr(VI) and Cd(II) on growth of Azotobacter sp. and Pichia sp., manifested by a biomass decrease of more than 50 % at heavy metal concentrations of 150-300 mg/L. The results confirmed close links between phytotoxicity of metals and their bioavailability for phytoextraction. Studies on the bioremediation potential of soils contaminated with Cr(VI) and Cd(II) using microbial strains focusing on Azotobacter sp. and Pichia sp. showed that the microbes can only tolerate heavy metal stress at low concentrations. These investigations on plants and microorganisms revealed their ability to withstand metal toxicity and develop tolerance to heavy metals.
原位生物修复过程对于污染控制和污染场地的清理非常重要。通过研究植物和微生物中污染物的吸收、生物转化、生物积累和毒性的自然机制，可以设计此类过程的研究和实施。在这里，研究了 Cr(VI)和 Cd(II)在单一离子溶液中不同浓度（30-300mg/L）下对蕹菜种子萌发和生长的植物毒性效应。这些研究还探讨了金属离子对从土壤中分离的固氮菌和毕赤酵母的生态毒性。通过称重干生物量和测定脱氢酶和过氧化氢酶的酶活性来估计微生物的生长。结果表明，Cr(VI)和 Cd(II)可以抑制蕹菜种子的萌发和根的发育，这取决于金属离子及其浓度。重金属的植物毒性效应也通过减少的干生物量得到了证实。毒性试验表明，Cr(VI)和 Cd(II)对固氮菌和毕赤酵母的生长有不利影响，在重金属浓度为 150-300mg/L 时，生物量减少了 50%以上。结果证实了金属的植物毒性与其用于植物提取的生物可利用性之间的密切联系。使用固氮菌和毕赤酵母等微生物菌株对污染有 Cr(VI)和 Cd(II)的土壤进行生物修复潜力的研究表明，微生物只能在低浓度重金属胁迫下耐受。这些对植物和微生物的研究揭示了它们对金属毒性的承受能力和对重金属的耐受性。
