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Wu L, Ngo HH, Wang C, Hou Y, Chen X, Guo W, Duan H, Ni BJ, Wei W. Lactobacillus inoculation mediated carboxylates and alcohols production from waste activated sludge fermentation system: Insight into process outcomes and metabolic network. BIORESOURCE TECHNOLOGY 2024; 409:131191. [PMID: 39094964 DOI: 10.1016/j.biortech.2024.131191] [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: 05/23/2024] [Revised: 07/28/2024] [Accepted: 07/30/2024] [Indexed: 08/04/2024]
Abstract
Producing medium chain fatty acids (MCFAs) from waste activated sludge (WAS) is crucial for sustainable chemical industries. This study addressed the electron donor requirement for MCFAs production by inoculating Lactobacillus at varying concentrations (7.94 × 1010, 3.18 × 1011, and 6.35 × 1011 cell/L) to supply lactate internally. Interestingly, the highest MCFAs yield (∼2000 mg COD/L) occurred at the lowest Lactobacillus inoculation. Higher inoculation concentrations redirected more carbon from WAS towards alcohols production rather than MCFAs generation, with up to 2852 mg COD/L alcohols obtained under 6.35 × 1011 cell/L inoculation. Clostridium dominance and increased genes abundance for substrate hydrolysis, lactate conversion, and MCFAs/alcohol production collectively enhanced WAS-derived MCFAs and alcohols synthesis after Lactobacillus inoculation. Overall, the strategy of Lactobacillus inoculation regulated fermentation outcomes and subsequent carbon recovery in WAS, presenting a sustainable technology to achieve liquid bio-energy production from underutilized wet wastes.
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Affiliation(s)
- Lan Wu
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Huu Hao Ngo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Chen Wang
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Yanan Hou
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Xueming Chen
- College of Environment and Safety Engineering, Fuzhou University, Fuzhou 350116, China
| | - Wenshan Guo
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Haoran Duan
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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Xu M, Gao P, Gao Y, Xiong SJ, Chen HQ, Shen XX. Impacts of microplastic type on the fate of antibiotic resistance genes and horizontal gene transfer mechanism during anaerobic digestion. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 360:121090. [PMID: 38772228 DOI: 10.1016/j.jenvman.2024.121090] [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: 11/30/2023] [Revised: 04/12/2024] [Accepted: 05/03/2024] [Indexed: 05/23/2024]
Abstract
Microplastics (MPs) and antibiotic resistance genes (ARGs) are important pollutants in waste activated sludge (WAS), but their interactions during anaerobic digestion (AD) still need to be further explored. This study investigated variations in ARGs, mobile genetic elements (MGEs), and host bacteria during AD under the pressure of polyamide (PA), polyethylene (PE), and polypropylene (PP). The results showed that the MPs increased methane production by 11.7-35.5%, and decreased ARG abundance by 5.6-24.6%. Correlation analysis showed that the decrease of MGEs (plasmid, prophage, etc.) promoted the decrease of the abundance of multidrug, aminoglycoside and tetracycline resistance genes. Metagenomic annotation revealed that the reduction of key host bacteria (Arenimonas, Lautropia, etc.) reduced the abundance of major ARGs (rsmA, rpoB2, etc.). Moreover, PP MPs contributed to a reduction in the abundance of functional genes related to the production of reactive oxygen species, ATP synthesis, and cell membrane permeability, which was conducive to reducing the potential for horizontal gene transfer of ARGs. These findings provide insights into the treatment of organic waste containing MPs.
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Affiliation(s)
- Ming Xu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China
| | - Peng Gao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China
| | - Yuan Gao
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China
| | - Shi-Jin Xiong
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China
| | - Hao-Qiang Chen
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China; College of Environment, Hohai University, Nanjing, 210098, China
| | - Xiao-Xiao Shen
- Institute of Water Science and Technology, Hohai University, Nanjing, 210098, China; The National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, 210098, China.
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Liu Y, Chen L, Duan Y, Li R, Yang Z, Liu S, Li G. Recent progress and prospects for chain elongation of transforming biomass waste into medium-chain fatty acids. CHEMOSPHERE 2024; 355:141823. [PMID: 38552798 DOI: 10.1016/j.chemosphere.2024.141823] [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: 02/04/2024] [Revised: 03/18/2024] [Accepted: 03/26/2024] [Indexed: 04/06/2024]
Abstract
Chain elongation technology utilises microorganisms in anaerobic digestion to transform waste biomass into medium-chain fatty acids that have greater economic value. This innovative technology expands upon traditional anaerobic digestion methods, requiring abundant substrates that serve as electron donors and acceptors, and inoculating microorganisms with chain elongation functions. While this process may result in the production of by-products and elicit competitive responses, toxicity suppression of microorganisms by substrates and products remains a significant obstacle to the industrialisation of chain elongation technology. This study provides a comprehensive overview of existing research on widely employed electron donors and their synthetic reactions, competitive reactions, inoculum selection, toxicity inhibition of substrates and products, and increased chain elongation approaches. Additionally, it presents actionable recommendations for future research and development endeavours in this domain, intending to inspire and guide researchers in advancing the frontiers of chain elongation technology.
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Affiliation(s)
- Yuhao Liu
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China.
| | - Long Chen
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Yacong Duan
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Ruihua Li
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Ziyan Yang
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Shuli Liu
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
| | - Guoting Li
- School of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou, 450046, Henan Province, China
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Ning Z, Wang X, Zhong W, Yang T, Dou D, Huang Y, Kong Q, Xu X. Influence of acetate-to-butyrate ratio on carbon chain elongation in anaerobic fermentation. BIORESOURCE TECHNOLOGY 2024; 395:130326. [PMID: 38242242 DOI: 10.1016/j.biortech.2024.130326] [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: 11/05/2023] [Revised: 12/27/2023] [Accepted: 01/11/2024] [Indexed: 01/21/2024]
Abstract
This study investigated the effect of electron acceptor (EA) distribution (acetate to butyrate ratio) on the carbon chain elongation (CCE) process. The results showed that the higher content of butyrate in the initial material led to the higher production of caproate. The maximum production of caproate was 3.74 ± 0.30 g·L-1, which was obtained when only butyrate was added as EA. Little caproate but much butyrate was produced where only acetate was added as EA. This indicated that CCE bacteria preferentially selected acetate as the EA to produce butyrate, and butyrate could be selected as EA to produce caproate only when the acetate content was much lower than butyrate. Unclassified_f_Dysgonomonadaceae, Massilibacterium, and Seramator were the predominant bacteria. Functional enzyme analysis showed that high butyrate content strengthened the fatty acid biosynthesis pathway and reverse β-oxidization pathway. The findings showed the importance of butyrate in CCE for caproate production.
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Affiliation(s)
- Zhifang Ning
- College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Xinyue Wang
- College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Weizhang Zhong
- College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China.
| | - Tianqi Yang
- College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Di Dou
- College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Yali Huang
- College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Qingchen Kong
- College of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
| | - Xingdan Xu
- Xingtai Ecological Environment Monitoring Center, Xingtai 054001, China
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Fernández-Blanco C, Veiga MC, Kennes C. Effect of pH and medium composition on chain elongation with Megasphaera hexanoica producing C 4-C 8 fatty acids. Front Microbiol 2023; 14:1281103. [PMID: 38029098 PMCID: PMC10653306 DOI: 10.3389/fmicb.2023.1281103] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Chain elongation technology, which involves fermentation with anaerobic bacteria, has gained attention for converting short and medium chain substrates into valuable and longer-chain products like medium chain fatty acids (MCFAs). In the recent past, the focus of studies with pure chain elongating cultures was on species of other genera, mainly Clostridium kluyveri. Recently, other chain elongators have been isolated that deserve further research, such as Megasphaera hexanoica. Methods In this study, batch studies were performed in bottles with two different media to establish the optimal conditions for growth of M. hexanoica: (a) a medium rich in different sources of nitrogen and (b) a medium whose only source of nitrogen is yeast extract. Also, batch bioreactor studies at pH values of 5.8, 6.5 and 7.2 were set up to study the fermentation of lactate (i.e., electron donor) and acetate (i.e., electron acceptor) by M. hexanoica. Results and discussion Batch bottle studies revealed the yeast extract (YE) containing medium as the most promising in terms of production/cost ratio, producing n-caproate rapidly up to 2.62 ± 0.24 g/L. Subsequent bioreactor experiments at pH 5.8, 6.5, and 7.2 confirmed consistent production profiles, yielding C4-C8 fatty acids. A fourth bioreactor experiment at pH 6.5 and doubling both lactate and acetate concentrations enhanced MCFA production, resulting in 3.7 g/L n-caproate and 1.5 g/L n-caprylate. H2 and CO2 production was observed in all fermentations, being especially high under the increased substrate conditions. Overall, this study provides insights into M. hexanoica's behavior in lactate-based chain elongation and highlights optimization potential for improved productivity.
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Affiliation(s)
| | | | - Christian Kennes
- Chemical Engineering Laboratory, Faculty of Sciences and Interdisciplinary Centre of Chemistry and Biology – Centro Interdisciplinar de Química y Biología (CICA), BIOENGIN Group, University of A Coruña, Coruña, Spain
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Chen J, Zhang X, Zhou L, Zhu Z, Wu Z, Zhang K, Wang Y, Ju T, Ji X, Jin D, Wu P, Zhang X. Metagenomics insights into high-rate nitrogen removal from municipal wastewater by integrated nitrification, partial denitrification and Anammox at an extremely short hydraulic retention time. BIORESOURCE TECHNOLOGY 2023; 387:129606. [PMID: 37572889 DOI: 10.1016/j.biortech.2023.129606] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/26/2023] [Accepted: 08/01/2023] [Indexed: 08/14/2023]
Abstract
To achieve high-rate nitrogen removal in municipal wastewater treatment through anaerobic ammonia oxidation (Anammox), the nitrification, partial denitrification, and Anammox processes were integrated by a step-feed strategy. An exceptional nitrogen removal load of 0.224 kg N/(m3·d) was achieved by gradient-reducing the hydraulic retention time (HRT) to 5 h. Metagenomic analysis demonstrated that Nitrosospira could express all genes encoding ammonia oxidation under low nitrogen and dissolved oxygen conditions (less than 0.5 mg/L), enabling complete nitrification. With the short of HRT, the relative abundance of Thauera increased from 2.8 % to 6.4 %. Frequent substrate exchanges at such extremely short HRT facilitated enhanced synergistic interactions among Nitrosospira, Thauera, and Candidatus Brocadia. These findings provide a comprehensive understanding of the utilization of Anammox combined processes for high-speed nitrogen removal in municipal wastewater treatment and the microbial interactions involved.
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Affiliation(s)
- Junjiang Chen
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Xiaonong Zhang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Li Zhou
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Zixuan Zhu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Zhiqiang Wu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Kangyu Zhang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Yiwen Wang
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Ting Ju
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Xu Ji
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Da Jin
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China
| | - Peng Wu
- School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou 215009, China; National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, No. 1 Kerui Road, Suzhou 215009, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, No. 1 Kerui Road,Suzhou 215009, China.
| | - Xingxing Zhang
- Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
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Li R, Hu M, Jiang X, Xu C. Metagenomic insights into the microbiota involved in lactate and butyrate production and manipulating their synthesis in alfalfa silage. J Appl Microbiol 2023; 134:lxad197. [PMID: 37660237 DOI: 10.1093/jambio/lxad197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/04/2023] [Accepted: 08/30/2023] [Indexed: 09/04/2023]
Abstract
AIMS Lactate and butyrate are important indicators of silage quality. However, the microorganisms and mechanisms responsible for lactate and butyrate production in silage are not well documented. METHODS AND RESULTS whole-metagenomic sequencing was used to analyse metabolic pathways, microbiota composition, functional genes, and their contributions to lactate and butyrate production in alfalfa silage with (SA) and without (CK) sucrose addition. Carbon metabolism was the most abundant metabolic pathway. We identified 11 and 2 functional genes associated with lactate and butyrate metabolism, respectively. Among them, D-lactate dehydrogenase (ldhA) and L-lactate dehydrogenase (ldhB) were most important for the transition between D/L-lactate and pyruvate and were primarily related to Lactobacillus in the SA group. The genes encoding L-lactate dehydrogenase (lldD), which decomposes lactate, were the most abundant and primarily associated with Enterobacter cloacae. Butyrate-related genes, mainly encoding butyryl-CoA: acetate CoA-transferase (but), were predominantly associated with Klebsiella oxytoca and Escherichia coli in the CK group. CONCLUSIONS Enterobacteriaceae and Lactobacillaceae were mainly responsible for butyrate and lactate formation, respectively.
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Affiliation(s)
- Rongrong Li
- College of Engineering, China Agricultural University, Beijing 100083, China
- College of Environment and Life Sciences, Weinan Normal University, Weinan 714099, China
| | - Ming Hu
- College of Environment and Life Sciences, Weinan Normal University, Weinan 714099, China
| | - Xin Jiang
- College of Engineering, China Agricultural University, Beijing 100083, China
| | - Chuncheng Xu
- College of Engineering, China Agricultural University, Beijing 100083, China
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