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Wu M, Wang Q, Wang C, Zeng Q, Li J, Wu H, Wu B, Xu H, Qiu Z. Strategy for enhancing Cr(VI)-contaminated soil remediation and safe utilization by microbial-humic acid-vermiculite-alginate immobilized biocomposite. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 243:113956. [PMID: 35964397 DOI: 10.1016/j.ecoenv.2022.113956] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/21/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Bioreduction is an efficient approach to in-situ remediate Cr(VI)-contaminated soil, but further strengthening methods are still urgently needed. Herein, a novel immobilized biocomposite (B-HA-VE-SA) was successfully synthesized by embedding a efficient strain Bacillus sp. CRB-7 with humic acid (HA) combined vermiculite (VE) and sodium alginate (SA). The performance and enhancement mechanism of the immobilized biocomposite on remediating Cr(VI)-contaminated soil were also investigated by analyzing the whole-genome of CRB-7, Cr(VI) detoxification, soil microecological regulation, and subsequent crop growth response. Genomic annotation demonstrated that CRB-7 contains multiple genes contributed to Cr(VI) tolerance, Cr(VI) reduction and other metals resistance. Results showed that embedded CRB-7 biocomposites exhibited more effective reduction of Cr(VI) in soil compared with control and free CRB-7 treatment, especially B-HA-VE-SA achieved the highest Cr(VI) removal efficiency (96.18%) and the residual Cr proportion (49.04%) via multiple mechanisms including carrier effects, nutrient sustained-release, and electron-shuttle effect enhanced the bioremediation process. Furthermore, the synergies of CRB-7 and immobilizers (HA, VE and SA) significantly improved soil microecology (soil enzyme activities, microbial quantity and diversity), and engendered the evolution of microbial community composition and functional pathways. Consequently, pot experiments (Brassica napus L.) verified the plant-growth-promoting (12.00-18.00% and 43.82-69.00% higher in emergence rate and biomass) and Cr-accumulation-reducing effects (19.47-91.09% and 29.11-89.80% lower in root and aerial parts) of free and immobilized CRB-7. Taken together, these findings highlighted the superiority of B-HA-VE-SA in simultaneous remediation, microecological improvement and safe utilization of Cr(VI)-contaminated soil.
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Affiliation(s)
- Minghui Wu
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, PR China
| | - Qiqi Wang
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, PR China
| | - Can Wang
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, PR China
| | - Qilu Zeng
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, PR China
| | - Jianpeng Li
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, PR China
| | - Han Wu
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, PR China
| | - Bin Wu
- College of Ecology and Environment, Chengdu University of Technology, 1# Dongsanlu, Erxianqiao, Chengdu 610059, Sichuan, PR China
| | - Heng Xu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, Sichuan, PR China.
| | - Zhongping Qiu
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, PR China.
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