Microbial induced phosphate precipitation accelerate lead mineralization to alleviate nucleotide metabolism inhibition and alter Penicillium oxalicum's adaptive cellular machinery.

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.