# Enhanced Effect of Phytoextraction on Arsenic-Contaminated Soil by Microbial Reduction
###### Abstract  
The gradually increasing presence of arsenic, a highly toxic heavy metal, poses a significant threat to both soil environmental safety and human health. _Pteris vittata_ has long been recognized as an efficient hyperaccumulator plant for arsenic pollution. However, the pattern of arsenic accumulation in soil impacts its bioavailability and restricts the extraction efficiency of _Pteris vittata_. To address this issue, microorganisms have the potential to improve the arsenic accumulation efficiency of _Pteris vittata_. In this work, we employed anthropogenic enrichment methods to extract functional iron-sulfur-reducing bacteria from soil as a raw material. These bacteria were then utilized to assist _Pteris vittata_ in the phytoremediation of arsenic-contaminated soil. Furthermore, the utilization of organic fertilizer produced from fermented crop straw significantly boosted the remediation effect. This led to an increase in the accumulation efficiency of arsenic by _Pteris vittata_ by 87.56%, while simultaneously reducing the content of available arsenic in the soil by 98.36%. Finally, the experimental phenomena were studied through a soil-microbial batch leaching test and plant potting test. And the mechanism of the microorganism-catalyzed soil iron-sulfur geochemical cycle on arsenic release and transformation in soil as well as the extraction effect of _Pteris vittata_ were systematically investigated using ICP, BCR sequential extraction and XPS analysis. The results demonstrated that using iron-sulfur-reducing microorganisms to enhance the phytoremediation effect is an effective strategy in the field of ecological restoration. arsenic-contaminated soil; phytoremediation; microbial reduction; _Pteris vittata_; iron-sulfur-reducing bacteria +
Footnote †: journal: Applied sciences  
such as translocation, accumulation, transport, transformation and volatilization to remove arsenic from soil [11]. Since inorganic arsenic interferes with plant metabolic processes and inhibits plant growth, phytoremediation requires plants with high arsenic resistance [12]. Earlier, researchers used Carex rostrata, Eriophorum, angustifoilium, Phragmites, etc., for phytoremediation studies of arsenic-contaminated soils [13]; the results were unsatisfactory until _Pteris vittata_, an arsenic hyperaccumulator, was discovered. The roots of _Pteris vittata_ have a strong absorption capacity for arsenic, and its rhizomes, which have a unique set of protective mechanisms to guard against the toxic effects of high concentrations of arsenic, can efficiently translocate arsenic [14]. As a result, _Pteris vittata_ has become a reliable candidate for the phytoremediation of arsenic-contaminated soil [15]. The effectiveness of phytoremediation towards arsenic is influenced by various factors. Only soluble arsenic can be absorbed by the roots of _Pteris vittata_ during the remediation process, and thus the fractionation of arsenic in the soil plays a significant role. The mobility and bioavailability of arsenic in soil can be altered by microorganisms through a variety of reactions, including adsorption, oxidation and reduction, complexation, transformation and volatilization [16]. Therefore, many studies focus on the microorganisms which could assist _Pteris vittata_ in the remediation of arsenic-containing soil. And it has been found that the growth of Pteris vittate maintains a dynamic equilibrium relationship with the variety of microbial communities in the rhizosphere as well as the speciation and level of arsenic in the rhizospheric soil [17]. Therefore, introducing functional strains exogenously may trigger changes in the rhizosphere's microbial community structure, leading to alterations in arsenic release, speciation, _Pteris vittata_ biomass and arsenic accumulation. For instance, [PERSON] et al. [18] discovered that the arsenic accumulated by _Pteris vittata_ was increased by an Enterobacter sp. E1 strain, which enhanced the desorption and reduction of arsenic in the iron-hydroxide-bound state. [PERSON] et al.