Department of Environmental Science and Engineering, College of Environment and Resources, Xiangtan University, Xiangtan 411105, PR China.
Department of Environmental Science and Engineering, College of Environment and Resources, Xiangtan University, Xiangtan 411105, PR China.
J Hazard Mater. 2022 Oct 5;439:129675. doi: 10.1016/j.jhazmat.2022.129675. Epub 2022 Jul 23.
Microbial-induced phosphate (P) precipitation (MIPP) based on P-solubilizing microorganisms (PSM) is regarded as a promising approach to bioimmobilize environmental lead (Pb). Nevertheless, the underlying changes of Pb biotoxicity in PSM during MIPP process were rarely discussed. The current study explored the Pb immobilization and metabolic changes in PSM Penicillium oxalicum postexposure to Pb and/or tricalcium phosphate (TCP). TCP addition significantly increased soluble P concentrations, accelerated extracellular Pb mineralization, and improved antioxidative enzyme activities in P. oxalicum during MIPP process. Secondary Pb biomineralization products were measured as hydroxypyromorphite [Pb(PO)(OH)]. Using untargeted metabolomic and transcriptomics, we found that Pb exposure stimulated the membrane integrity deterioration and nucleotide metabolism obstruction of P. oxalicum. Correspondingly, P. oxalicum could produce higher levels of gamma-aminobutyric acid (GABA) to enhance the adaptive cellular machineries under Pb stress. While the MIPP process improved extracellular Pb mineralization, consequently alleviating the nucleotide metabolism inhibition and membrane deterioration. Multi-omics results suggested that GABA degradation pathway was stimulated for arginine biosynthesis and TCA cycle after Pb mineralization. These results provided new biomolecular information underlying the Pb exposure biotoxicities to microorganisms in MIPP before the application of this approach in environmental Pb remediation.
基于解磷微生物（PSM）的微生物诱导磷沉淀（MIPP）被认为是生物固定环境铅（Pb）的一种很有前途的方法。然而，在 MIPP 过程中，PSM 中 Pb 生物毒性的潜在变化很少被讨论。本研究探讨了 Pb 暴露后或暴露于磷酸三钙（TCP）后草酸青霉（Penicillium oxalicum）中 Pb 的固定和代谢变化。TCP 的添加显著增加了可溶性 P 浓度，加速了 MIPP 过程中外源 Pb 的矿化，并提高了草酸青霉中的抗氧化酶活性。次生 Pb 生物矿化产物被测量为羟磷灰石[Pb(PO)(OH)]。通过非靶向代谢组学和转录组学，我们发现 Pb 暴露刺激了草酸青霉的膜完整性恶化和核苷酸代谢受阻。相应地，草酸青霉可以产生更高水平的γ-氨基丁酸（GABA），以增强 Pb 胁迫下的适应性细胞机制。而 MIPP 过程则提高了细胞外 Pb 的矿化程度，从而减轻了核苷酸代谢抑制和膜恶化。多组学结果表明，GABA 降解途径被刺激，用于 Pb 矿化后的精氨酸生物合成和 TCA 循环。这些结果为在该方法应用于环境 Pb 修复之前，提供了微生物在 MIPP 中暴露于 Pb 时生物毒性的新生物分子信息。
