1
|
Li Q, Xu Y, Chen S, Liang C, Guo W, Ngo HH, Peng L. Inorganic carbon limitation decreases ammonium removal and N 2O production in the algae-nitrifying bacteria symbiosis system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 928:172440. [PMID: 38614328 DOI: 10.1016/j.scitotenv.2024.172440] [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: 02/05/2024] [Revised: 04/08/2024] [Accepted: 04/10/2024] [Indexed: 04/15/2024]
Abstract
Ammonium removal by a symbiosis system of algae (Chlorella vulgaris) and nitrifying bacteria was evaluated in a long-term photo-sequencing batch reactor under varying influent inorganic carbon (IC) concentrations (15, 10, 5 and 2.5 mmol L-1) and different nitrogen loading rate (NLR) conditions (270 and 540 mg-N L-1 d-1). The IC/N ratios provided were 2.33, 1.56, 0.78 and 0.39, respectively, for an influent NH4+-N concentration of 90 mg-N L-1 (6.43 mmol L-1). The results confirmed that both ammonium removal and N2O production were positively related with IC concentration. Satisfactory ammonium removal efficiencies (>98 %) and rates (29-34 mg-N gVSS-1 h-1) were achieved regardless of NLR levels under sufficient IC of 10 and 15 mmol L-1, while insufficient IC at 2.5 mmol L-1 led to the lowest ammonium removal rates of 0 mg-N gVSS-1 h-1. The ammonia oxidation process by ammonia oxidizing bacteria (AOB) played a predominant role over the algae assimilation process in ammonium removal. Long-time IC deficiency also resulted in the decrease in biomass and pigments of algae and nitrifying bacteria. IC limitation led to the decreasing N2O production, probably due to its negative effect on ammonia oxidation by AOB. The optimal IC concentration was determined to be 10 mmol L-1 (i.e., IC/N of 1.56, alkalinity of 500 mg CaCO3 L-1) in the algae-bacteria symbiosis reactor, corresponding to higher ammonia oxidation rate of ∼41 mg-N gVSS-1 h-1 and lower N2O emission factor of 0.13 %. This suggests regulating IC concentrations to achieve high ammonium removal and low carbon emission simultaneously in the algae-bacteria symbiosis wastewater treatment process.
Collapse
Affiliation(s)
- Qi Li
- Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Yifeng Xu
- Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China.
| | - Shi Chen
- School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Chuanzhou Liang
- Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Huu Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Lai Peng
- Key Laboratory of Green Utilization of Critical Non-metallic Mineral Resources, Ministry of Education, Wuhan University of Technology, Wuhan 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China.
| |
Collapse
|
2
|
Yadav I, Rautela A, Gangwar A, Wagadre L, Rawat S, Kumar S. Enhancement of isoprene production in engineered Synechococcus elongatus UTEX 2973 by metabolic pathway inhibition and machine learning-based optimization strategy. BIORESOURCE TECHNOLOGY 2023; 387:129677. [PMID: 37579861 DOI: 10.1016/j.biortech.2023.129677] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 08/16/2023]
Abstract
An engineered Synechococcus elongatus UTEX 2973-IspS.IDI is used to enhance isoprene production through geranyl diphosphate synthase (CrtE) inhibition and process parameters (light intensity, NaHCO3 and growth temperature) optimization approach. A cumulative isoprene production of 1.21 mg/gDCW was achieved with productivity of 12.6 μg/gDCW/h in culture supplemented with 20 μg/mL alendronate. This inhibition strategy improvises the cumulative isoprene production 5.76-fold in presence of alendronate. The maximum cumulative production of isoprene is observed to be 5.22 and 6.20 mg/gDCW (54.4 and 64.6 μg/gDCW/h) at statistical and artificial neural network genetic algorithm (ANN-GA) optimized conditions, respectively. The overall increase of isoprene production is found to be 29.52-fold using an integrated approach of inhibition and ANN-GA optimization in comparison to unoptimized cultures without alendronate. This study reveals that alendronate use as a potential inhibitor and machine learning based optimization is a better approach in comparison to statistical optimization to enhance the isoprene production.
Collapse
Affiliation(s)
- Indrajeet Yadav
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh 221005, India
| | - Akhil Rautela
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh 221005, India
| | - Agendra Gangwar
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh 221005, India
| | - Lokesh Wagadre
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh 221005, India
| | - Shweta Rawat
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh 221005, India
| | - Sanjay Kumar
- School of Biochemical Engineering, IIT (BHU) Varanasi, Varanasi, Uttar Pradesh 221005, India.
| |
Collapse
|
3
|
Díaz-Galián MV, Vega-Rodríguez MA. Many-objective approach based on problem-aware mutation operators for protein encoding. Inf Sci (N Y) 2022. [DOI: 10.1016/j.ins.2022.09.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|