1
|
Shao W, Qian Y, Zhai X, Xu L, Guo H, Zhang M, Qiao W. Mechanisms of nanoscale zero-valent iron mediating aerobic denitrification in Pseudomonas stutzeri by promoting electron transfer and gene expression. BIORESOURCE TECHNOLOGY 2024; 394:130202. [PMID: 38092073 DOI: 10.1016/j.biortech.2023.130202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 12/09/2023] [Accepted: 12/11/2023] [Indexed: 12/17/2023]
Abstract
Aerobic denitrification and its mechanism by P. stutzeri was investigated in the presence of nanoscale zero-valent iron (nZVI). The removal of nitrate and ammonia was accelerated and the nitrite nitrogen accumulation was reduced by nZVI. The particle size and dosage of nZVI were key factors for enhancing aerobic denitrification. nZVI reduced the negative effects of low carbon/nitrogen, heavy metals, surfactants and salts to aerobic denitrification. nZVI and its dissolved irons were adsorbed into the bacteria cells, enhancing the transfer of electrons from nicotinamide adenine dinucleotide (NADH) to nitrate reductase. Moreover, the activities of NADH-ubiquinone reductase involved in the respiratory system, and the denitrifying enzymes were increased. The expression of denitrifying enzyme genes napA and nirS, as well as the iron metabolism gene fur, were promoted in the presence of nZVI. This work provides a strategy for enhancing the biological denitrification of wastewater using the bio-stimulation of nanomaterials.
Collapse
Affiliation(s)
- Weizhen Shao
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Yi Qian
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Xiaopeng Zhai
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Lijie Xu
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - He Guo
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Ming Zhang
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Weichuan Qiao
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China.
| |
Collapse
|
2
|
Cao S, Lan Y, Du R, Peng Y. Robustness and stability of acetate-driven partial denitrification (PD) in response to high COD/NO 3--N. CHEMOSPHERE 2023; 322:138213. [PMID: 36822519 DOI: 10.1016/j.chemosphere.2023.138213] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/12/2023] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Partial Denitrification (PD) producing nitrite for anammox may face the issue of relatively high chemical oxygen demand (COD) loading (i.e., COD/NO3--N) due to real wastewater being changed in substrate concentration and flowrate. In this study, three PD systems (R1, R2, R3) with sodium acetate providing electrons were developed to investigate the influence of the relatively high COD/NO3--N ratios (4.0, 6.0, and 8.0) on NO2--N production and the subsequent recoverability. It was found that a relatively high NO2--N production with nitrate-to-nitrite transformation ratio (NTR) of 74.0% could be still obtained despite COD/NO3--N even improving to 8.0 under limited reaction time (10 min) with small nitrate remaining. However, a deteriorated nitrite production was observed with sufficient reaction time (15 min) with NTR being lowered to 19.2%. Delightedly, when reducing influent COD/NO3--N to a normal level of 3.0, PD with high nitrite production was rapidly achieved after suffering from a relatively high COD/NO3--N (4.0-8.0) for 130 cycles. Besides, it was found the relatively high COD/NO3--N had a minor influence on the recoverability of PD, as evidenced by the close NTRs. Microbial analysis revealed the relative abundance of PD functional bacteria, Thauera, decreased under high COD/NO3--N, while it is still highly dominated in the systems, varying from 75.1% in R1 to 62.8% in R3 after around 110-cycles recovery. Furthermore, it appeared that the high pH (9.1-9.2) induced by sodium acetate also likely played a role in maintaining the excellent PD. Overall, this study demonstrated the robustness and stability of acetate-driven PD in response to high COD/NO3--N, further informing the technological superiority of PD in supplying stable and efficient nitrite, which provided solid technical support to apply it with anammox for high-efficient N removal.
Collapse
Affiliation(s)
- Shenbin Cao
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing, 100124, China; College of Architecture and Civil Engineering, Faculty of Architecture, Civil and Transportation Engineering (FACTE), Beijing University of Technology, Beijing, 100124, China
| | - Yu Lan
- College of Architecture and Civil Engineering, Faculty of Architecture, Civil and Transportation Engineering (FACTE), Beijing University of Technology, Beijing, 100124, China
| | - Rui Du
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing, 100124, China.
| | - Yongzhen Peng
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing, 100124, China
| |
Collapse
|
3
|
C-, N-, S-, and P-Substrate Spectra in and the Impact of Abiotic Factors on Assessing the Biotechnological Potential of Paracoccus pantotrophus. Appl Microbiol 2023. [DOI: 10.3390/applmicrobiol3010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Modern biotechnology benefits from the introduction of novel chassis organisms in remedying the limitations of already-established strains. For this, Paracoccus pantotrophus was chosen for in-depth assessment. Its unique broad metabolism and robustness against abiotic stressors make this strain a well-suited chassis candidate. This study set out to comprehensively overview abiotic influences on the growth performance of five P. pantotrophus strains. These data can aid in assessing the suitability of this genus for chassis development by using the type strain as a preliminary model organism. The five P. pantotrophus strains DSM 2944T, DSM 11072, DSM 11073, DSM 11104, and DSM 65 were investigated regarding their growth on various carbon sources and other nutrients. Our data show a high tolerance against osmotic pressure for the type strain with both salts and organic osmolytes. It was further observed that P. pantotrophus prefers organic acids over sugars. All of the tested strains were able to grow on short-chain alkanes, which would make P. pantotrophus a candidate for bioremediation and the upcycling of plastics. In conclusion, we were able to gain insights into several P. pantotrophus strains, which will aid in further introducing this species, or even another species from this genus, as a candidate for future biotechnological processes.
Collapse
|
4
|
Wang Z, Su J, Ali A, Sun Y, Li Y, Yang W, Zhang R. Enhanced removal of fluoride, nitrate, and calcium using self-assembled fungus-flexible fiber composite microspheres combined with microbially induced calcium precipitation. CHEMOSPHERE 2022; 302:134848. [PMID: 35526689 DOI: 10.1016/j.chemosphere.2022.134848] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/26/2022] [Accepted: 05/02/2022] [Indexed: 06/14/2023]
Abstract
Self-assembled fungus-flexible fiber composite microspheres (SFFMs) were firstly combined with microbially induced calcium precipitation (MICP) in a continuous-flow bioreactor and achieved the efficient removal of fluoride (F-), nitrate (NO3-), and calcium (Ca2+). Under the influent F- of 3.0 mg L-1, pH of 7.0, and HRT of 8 h, the average removal efficiencies reached 77.54%, 99.39%, and 67.25% (0.29, 2.03, and 8.34 mg L-1 h-1), respectively. Fluorescence spectrum and flow cytometry analyses indicated that F- content significantly affected the metabolism and viability of bacteria. SEM images showed that flexible fibers and intertwined hyphae provided effective locations for bacterial colonization in SFFMs. The precipitated products were characterized by XRD and FTIR, which revealed that F- was mainly removed in the form of calcium fluoride and calcium fluorophosphate (CaF2 and Ca5(PO4)3F). High-throughput analysis at different levels demonstrated that Pseudomonas sp. WZ39 acted as the core strain, which played a crucial role in the bioreactor. The mechanism of enhanced denitrification was attributed to minor F- stress and bioaugmentation technology. This study highlighted the superiorities of SFFMs and MICP combined remediation and documented a promising option for F-, NO3-, and Ca2+ removal.
Collapse
Affiliation(s)
- Zhao Wang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Amjad Ali
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Yi Sun
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Yifei Li
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Wenshuo Yang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Ruijie Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| |
Collapse
|