Biochar: An effective measure to strengthen phosphorus solubilizing microorganisms for remediation of heavy metal pollution in soil

Abstract

Introduction: Phosphorus solubilizing microbial remediation is a sustainable technology for soil heavy metal remediation 1.1 Microbial remediation is an effective measure to achieve sustainable remediation of heavy metals in soil Heavy metals (HMs) pollution of soil caused by human activities is a serious threat to human health and sustainable social development. The insidious, lagging, long-term, inhomogeneous and irreversible nature of heavy metal pollution has led to serious degradation of soil ecological structure and function. Most importantly, heavy metals in soil can be enriched into animals or humans through the food chain (food crops), threatening human health and life (Jan et al., 2015). Therefore, remediation of heavy metals for soils has been one of the key issues in the field of environmental remediation. Compared with physical or chemical remediation technologies, microbial remediation technology is gradually recognized for its green, low cost, easy operation and long sustainability (Maity et al., 2019). Although most HMs are difficult to degrade and remove by microorganisms in soil, microorganisms (microbial uptake, transformation, mineralization or immobilization) can convert HMs to less toxic forms or reduce their mobility (Kotrba and Ruml, 2000;Lin et al., 2023). Among them, biomineralization is a common and effective method for remediation of HMs pollution in soil, which is mainly through the interaction between microorganisms and HMs to form mineral crystals (such as, phosphate, carbonate, sulfate, arsenate, fluoride, oxide, hydroxide, and manganese oxide, etc.) outside, between or within the cells of microorganisms (Tayang and Songachan, 2021;Lin et al., 2023). Not only that, among up to 60 kinds of biomineralization products, metal phosphates have been of concern due to their high stability.

Phosphate solubilizing microorganisms: a sustainability strategy to improve urban ecosystems

“…Studies have shown that PSMs have a good fixation effect on heavy metal ions, such as Cr 6+ , Co 2+ , Cd 2+ , Zn 2+ , Cu 2+ , and Pb 2+ in soil (Qian et al, 2019;Hu and Chen, 2023). PSMs can first dissolve insoluble phosphorus sources by releasing organic acids and enzymes and converting them to PO 4 3− which binds to heavy metals to form phosphate precipitates and can greatly reduce the amount of free heavy metal ions in the soil (Chen et al, 2023). Second, PSM can secrete organic acids, indoleacetic acids, iron carriers, and other substances with oxidizing or reducing properties, thereby altering the metal valence state and diminishing the toxicity of toxic metals (Lai et al, 2022;Yu et al, 2022).…”

Phosphate solubilizing microorganism: a green measure to effectively control and regulate heavy metal pollution in agricultural soils

“…PSM plays a vital role in all three main processes that affect the soil phosphorus content [dissolution-precipitation, adsorption-desorption, and mineralization-immobilization (Sharma et al, 2013 )]. It is worth noting that PSMs with high heavy metal resistance can alleviate HMs toxicity and the accumulation of HMs in plants through a range of mechanisms (Ahemad, 2015 ; Chen et al, 2023 ; Figure 1 ). In general, the tolerance of PSM to HMs is related to the isolation environment of the strain.…”

“…PSM mainly remediates heavy metal contaminated soil through bioadsorption and enrichment, biotransformation, and bioprecipitation (Chen et al, 2023 ). Firstly, PSM can reduce the bioavailability of HMs by synthesizing metal-binding proteins (such as metallothionein) and releasing siderophores to chelate HMs and accumulate them in the cells (Gupta and Kumar, 2017 ).…”

Machine learning: An effective technical method for future use in assessing the effectiveness of phosphorus-dissolving microbial agroremediation

“…6) The use of phosphate solubilizing microorganisms can also reduce the use of chemical fertilizers and pesticides, reducing the negative impact on the environment (Ahemad, 2015). In addition, the good affinity of PSM allows it to be used together with other materials to improve soil properties and remediate environmental pollution (Chen et al, 2019;Feng et al, 2022;Lai et al, 2022;Chen et al, 2023a).…”