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He K, Liu Y, Tian L, He W, Cheng Q. Review in anaerobic digestion of food waste. Heliyon 2024; 10:e28200. [PMID: 38560199 PMCID: PMC10979283 DOI: 10.1016/j.heliyon.2024.e28200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 02/27/2024] [Accepted: 03/13/2024] [Indexed: 04/04/2024] Open
Abstract
Due to the special property of food waste (FW), anaerobic digestion of food waste is facing many challenges like foaming, acidification, ammonia nitrogen and (NH4+-N) inhibition which resulted in a low biogas yield. A better understanding on the problems exiting in the FW anaerobic digestion would enhance the bio-energy recovery and increase the stable operation. Meanwhile, to overcome the bottle necks, pretreatment, co-digestion and additives is proposed as well as the solutions to improve biogas yield in FW digestion system. At last, future research directions regarding FW anaerobic digestion were proposed.
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Affiliation(s)
- Kefang He
- School of Management, Wuhan Polytechnic University, China
| | - Ying Liu
- School of Chemical and Environmental Engineering, Wuhan Polytechnic University, China
| | - Longjin Tian
- School of Chemical and Environmental Engineering, Wuhan Polytechnic University, China
| | - Wanyou He
- School of Management, Wuhan Polytechnic University, China
| | - Qunpeng Cheng
- School of Chemical and Environmental Engineering, Wuhan Polytechnic University, China
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Liu F, Cheng W, Xu J, Wang M, Wan T, Ren J, Li D, Xie Q. Promoting short-chain fatty acids production from sewage sludge via acidogenic fermentation: Optimized operation factors and iron-based persulfate activation system. CHEMOSPHERE 2023; 342:140148. [PMID: 37714473 DOI: 10.1016/j.chemosphere.2023.140148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 08/10/2023] [Accepted: 09/10/2023] [Indexed: 09/17/2023]
Abstract
Promoting short-chain fatty acids (SCFAs) production and ensuring the stability of SCFAs-producing process are becoming the two major issues for popularizing the acidogenic fermentation (AF). The key controlling operating and influencing factors during anaerobic fermentation process were thoroughly reviewed to facilitate better process performance prediction and to optimize the process control of SCFAs promotion. The wide utilization of iron salt flocculants during wastewater treatment could result in iron accumulating in sewage sludge which influenced AF performance. Additionally, appropriate ferric chloride (FC) could promote the SCFAs accumulation, while poly ferric sulfate (PFS) inhibited the bioprocess. Iron/persulfate (PS) system was proved to effectively enhance the SCFAs production while mechanism analysis revealed that the strong oxidizing radicals remarkably enhanced the solubilization and hydrolysis. Moreover, the changes of oxidation-reduction potential (ORP) and pH caused by iron/PS system exhibited more negative effects on the methanogens, comparing to the acidogenic bacteria. Furthermore, performance and mechanisms of different iron species-activating PS, organic chelating agents and iron-rich biochar derived from sewage sludge were also elucidated to extend and strengthen understanding of the iron/PS system for enhancing SCFAs production. Considering the large amount of generated Fe-sludge and the multiple benefits of iron activating PS system, carbon neutral wastewater treatment plants (WWTPs) were proposed with Fe-sludge as a promising recycling composite to improve AF performance. It is expected that this review can deepen the knowledge of optimizing AF process and improving the iron/PS system for enhancing SCFAs production and provide useful insights to researchers in this field.
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Affiliation(s)
- Faxin Liu
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, NO.5, South Jinhua Road, Xi'an, Shaanxi, 710048, China
| | - Wen Cheng
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, NO.5, South Jinhua Road, Xi'an, Shaanxi, 710048, China.
| | - Jianping Xu
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, NO.5, South Jinhua Road, Xi'an, Shaanxi, 710048, China
| | - Min Wang
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, NO.5, South Jinhua Road, Xi'an, Shaanxi, 710048, China
| | - Tian Wan
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, NO.5, South Jinhua Road, Xi'an, Shaanxi, 710048, China
| | - Jiehui Ren
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, NO.5, South Jinhua Road, Xi'an, Shaanxi, 710048, China
| | - Dong Li
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, NO.5, South Jinhua Road, Xi'an, Shaanxi, 710048, China
| | - Qiqi Xie
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, NO.5, South Jinhua Road, Xi'an, Shaanxi, 710048, China
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Haffiez N, Chung TH, Zakaria BS, Shahidi M, Mezbahuddin S, Hai FI, Dhar BR. A critical review of process parameters influencing the fate of antibiotic resistance genes in the anaerobic digestion of organic waste. BIORESOURCE TECHNOLOGY 2022; 354:127189. [PMID: 35439559 DOI: 10.1016/j.biortech.2022.127189] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/13/2022] [Accepted: 04/15/2022] [Indexed: 06/14/2023]
Abstract
The overuse and inappropriate disposal of antibiotics raised severe public health risks worldwide. Specifically, the incomplete antibiotics metabolism in human and animal bodies contributes to the significant release of antibiotics into the natural ecosystems and the proliferation of antibiotic-resistant bacteria carrying antibiotic-resistant genes. Moreover, the organic feedstocks used for anaerobic digestion are often highly-rich in residual antibiotics and antibiotic-resistant genes. Hence, understanding their fate during anaerobic digestion has become a significant research focus recently. Previous studies demonstrated that various process parameters could considerably influence the propagation of the antibiotic-resistant genes during anaerobic digestion and their transmission via land application of digestate. This review article scrutinizes the influences of process parameters on antibiotic-resistant genes propagation in anaerobic digestion and the inherent fundamentals behind their effects. Based on the literature review, critical research gaps and challenges are summarized to guide the prospects for future studies.
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Affiliation(s)
- Nervana Haffiez
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Tae Hyun Chung
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Basem S Zakaria
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Manjila Shahidi
- 4S Analytics & Modelling Ltd., Edmonton, AB, T6W 3V6, Canada
| | | | - Faisal I Hai
- Strategic Water Infrastructure Laboratory, School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Bipro Ranjan Dhar
- Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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Al-Samet MA, Goto M, Mubarak NM, Al-Muraisy SA. Evaluating the biomethane potential from the anaerobic co-digestion of palm oil mill effluent, food waste, and sewage sludge in Malaysia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:67632-67645. [PMID: 34255262 DOI: 10.1007/s11356-021-15287-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
The ever-increasing organic waste generation in Malaysia is a significant contributor to greenhouse gas (GHG) emissions. However, organic wastes can be utilized to produce biogas by anaerobic digestion, which is a promising option for both energy and material recovery from organic wastes with high moisture content. Therefore, this study was formulated to investigate the feasibility of anaerobic co-digestion of three types of organic wastes generated in significantly huge quantities in Malaysia, namely palm oil mill effluent (POME), food waste (FW), and sewage sludge (SWS). The biomethane potential (BMP) test was used to evaluate the biomethane potential from these organic wastes under mesophilic conditions to establish a stable and balanced microbial community, which may lack in mono-digestion, to improve biogas production. Comparative performance was made at different food to microorganism (F/M) ratios to investigate methane production in three groups of assays, namely A, B, and C. In groups A and B, the effect of F/M ratio variation on methane production was investigated, while in group C, the effect of varying the co-substrate mixture on methane yield was examined. The findings showed that the highest methane yields achieved for mono-digestion of POME and SWS in group A were 164.44 mL-CH4/g-CODadded and 65.34 mL-CH4/g-CODadded, respectively, at an F/M ratio of 0.8 and 197.90 mL-CH4/g-CODadded for FW in group B at an F/M ratio of 0.5. In addition, the highest methane yield achieved from the anaerobic co-digestion was at 151.47 mL-CH4/g-CODadded from the co-digestion of the POME and SWS (50:50) at an F/M ratio of 1.7 in group A. Both AD and AcoD were tested to fit into two kinetic models: the modified Gompertz and the transfer function models. The results showed that the modified Gompertz model had a better fit and was more adjusted to the experimental results for both AD and AcoD. The importance of this research lies in the economics of anaerobically co-digesting these abundance feedstocks and the variations in their characteristics which were found to increase their methane yield and process efficiency in anaerobic co-digestion.
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Affiliation(s)
- Mohamed Abdulrahman Al-Samet
- Malaysia-Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100, Kuala Lumpur, Malaysia.
| | - Masafumi Goto
- Malaysia-Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100, Kuala Lumpur, Malaysia
| | - Nabisab Mujawar Mubarak
- Department of Chemical and Energy Engineering, Faculty of Engineering and Science, Curtin University, 98009, Miri, Sarawak, Malaysia.
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Rahman MS, Hoque MN, Puspo JA, Islam MR, Das N, Siddique MA, Hossain MA, Sultana M. Microbiome signature and diversity regulates the level of energy production under anaerobic condition. Sci Rep 2021; 11:19777. [PMID: 34611238 PMCID: PMC8492712 DOI: 10.1038/s41598-021-99104-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/13/2021] [Indexed: 02/08/2023] Open
Abstract
The microbiome of the anaerobic digester (AD) regulates the level of energy production. To assess the microbiome diversity and composition in different stages of anaerobic digestion, we collected 16 samples from the AD of cow dung (CD) origin. The samples were categorized into four groups (Group-I, Group-II, Group-III and Group-IV) based on the level of energy production (CH4%), and sequenced through whole metagenome sequencing (WMS). Group-I (n = 2) belonged to initial time of energy production whereas Group-II (n = 5), Group-III (n = 5), and Group-IV (n = 4) had 21-34%, 47-58% and 71-74% of CH4, respectively. The physicochemical analysis revealed that level of energy production (CH4%) had significant positive correlation with digester pH (r = 0.92, p < 0.001), O2 level (%) (r = 0.54, p < 0.05), and environmental temperature (°C) (r = 0.57, p < 0.05). The WMS data mapped to 2800 distinct bacterial, archaeal and viral genomes through PathoScope (PS) and MG-RAST (MR) analyses. We detected 768, 1421, 1819 and 1774 bacterial strains in Group-I, Group-II, Group-III and Group-IV, respectively through PS analysis which were represented by Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, Spirochaetes and Fibrobacteres phyla (> 93.0% of the total abundances). Simultaneously, 343 archaeal strains were detected, of which 95.90% strains shared across four metagenomes. We identified 43 dominant species including 31 bacterial and 12 archaeal species in AD microbiomes, of which only archaea showed positive correlation with digester pH, CH4 concentration, pressure and temperature (Spearman correlation; r > 0.6, p < 0.01). The indicator species analysis showed that the species Methanosarcina vacuolate, Dehalococcoides mccartyi, Methanosarcina sp. Kolksee and Methanosarcina barkeri were highly specific for energy production. The correlation network analysis showed that different strains of Euryarcheota and Firmicutes phyla exhibited significant correlation (p = 0.021, Kruskal-Wallis test; with a cutoff of 1.0) with the highest level (74.1%) of energy production (Group-IV). In addition, top CH4 producing microbiomes showed increased genomic functional activities related to one carbon and biotin metabolism, oxidative stress, proteolytic pathways, membrane-type-1-matrix-metalloproteinase (MT1-MMP) pericellular network, acetyl-CoA production, motility and chemotaxis. Importantly, the physicochemical properties of the AD including pH, CH4 concentration (%), pressure, temperature and environmental temperature were found to be positively correlated with these genomic functional potentials and distribution of ARGs and metal resistance pathways (Spearman correlation; r > 0.5, p < 0.01). This study reveals distinct changes in composition and diversity of the AD microbiomes including different indicator species, and their genomic features that are highly specific for energy production.
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Affiliation(s)
- M. Shaminur Rahman
- grid.8198.80000 0001 1498 6059Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh
| | - M. Nazmul Hoque
- grid.8198.80000 0001 1498 6059Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh ,grid.443108.a0000 0000 8550 5526Department of Gynecology, Obstetrics and Reproductive Health, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, 1706 Bangladesh
| | - Joynob Akter Puspo
- grid.8198.80000 0001 1498 6059Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh
| | - M. Rafiul Islam
- grid.8198.80000 0001 1498 6059Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh
| | - Niloy Das
- grid.8198.80000 0001 1498 6059Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh ,Surge Engineering (www.surgeengineering.com), Dhaka, 1205 Bangladesh
| | - Mohammad Anwar Siddique
- grid.8198.80000 0001 1498 6059Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh
| | - M. Anwar Hossain
- grid.8198.80000 0001 1498 6059Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh ,Present Address: Jashore University of Science and Technology, Jashore, 7408 Bangladesh
| | - Munawar Sultana
- grid.8198.80000 0001 1498 6059Department of Microbiology, University of Dhaka, Dhaka, 1000 Bangladesh
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Yang P, Peng Y, Tan H, Liu H, Wu D, Wang X, Li L, Peng X. Foaming mechanisms and control strategies during the anaerobic digestion of organic waste: A critical review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 779:146531. [PMID: 34030228 DOI: 10.1016/j.scitotenv.2021.146531] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 03/11/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Foaming is a problem that affects the efficient and stable operation of the anaerobic digestion process. Characterizing foaming mechanisms and developing early warning and foaming control methods is thus critically important. This review summarizes the correlation of process parameters, state parameters, and microbial communities with foaming in anaerobic digesters; discusses the applicability of the above-mentioned multi-scale parameters and foaming potential evaluation methods for the prediction of foaming risk; and introduces the principles and practical applications of antifoaming and defoaming methods. Multiple causes of foaming in anaerobic digestion systems have been identified, but a generalizable foaming mechanism has yet to be described. Further study of the correlation between extracellular polymeric substances and soluble microbial products and foaming may provide new insights into foaming mechanisms. Monitoring the foaming potential (including the volume expansion potential) is an effective approach for estimating the risk of foaming. An in-situ monitoring system for determining the foaming potential in anaerobic digestion sites could provide an early warning of foaming risk. Antifoaming methods based on operating parameter management and process regulation help prevent foaming from the source, and biological defoaming methods are highly targeted and efficient, which is a promising research direction. Clarifying foaming mechanisms will aid the development of active antifoaming methods and efficient biological defoaming methods.
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Affiliation(s)
- Pingjin Yang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Yun Peng
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Hanyue Tan
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Hengyi Liu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Di Wu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Xiaoming Wang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
| | - Lei Li
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
| | - Xuya Peng
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China
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Wang H, Fotidis IA, Yan Q, Angelidaki I. Feeding strategies of continuous biomethanation processes during increasing organic loading with lipids or glucose for avoiding potential inhibition. BIORESOURCE TECHNOLOGY 2021; 327:124812. [PMID: 33578353 DOI: 10.1016/j.biortech.2021.124812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Anaerobic co-digestion is a promising solution for nutrients balance and improvement of methane production in anaerobic digestion (AD) processes. However, the knowledge about the effects of different co-substrates in manure-based AD, and different feeding strategies, on the process performance and the methanogenic microbiome pathway, are still missing. Therefore, under harsh and slow stepwise increase of organic loading rate (OLR), by addition of lipids and carbohydrates as co-substrates in continuous reactors, this study elucidated their effect on methane production and methanogenic microbiome. The results showed that, when OLR increased by adding lipids, a severe inhibition due to accumulated long-chain fatty acids (LCFA) was observed, while no significant inhibition was obtained by addition of glucose. Additionally, the LCFA inhibition in the reactor fed with lipid was alleviated by slow stepwise feeding strategy that enriched aceticlastic Methanosarcina thermophile and Methanosaeta concilii, and hydrogenotrophic Methanobacterium methanogens.
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Affiliation(s)
- Han Wang
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China; Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Ioannis A Fotidis
- Department of Environmental Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark; School of Civil Engineering Southeast University Nanjing, 210096, China.
| | - Qun Yan
- School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Irini Angelidaki
- Department of Chemical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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Response Surface Methodology to Optimize Methane Production from Mesophilic Anaerobic Co-Digestion of Oily-Biological Sludge and Sugarcane Bagasse. SUSTAINABILITY 2020. [DOI: 10.3390/su12052116] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Oily-biological sludge (OBS) generated from petroleum refineries has high toxicity. Therefore, it needs an appropriate disposal method to reduce the negative impacts on the environment. The anaerobic co-digestion process is an effective method that manages and converts organic waste to energy. For effective anaerobic digestion, a co-substrate would be required to provide a suitable environment for anaerobic bacteria. In oily-biological sludge, the carbon/nitrogen (C/N) ratio and volatile solids (VS) content are very low. Therefore, it needs to be digested with organic waste that has a high C/N ratio and high VS content. This study investigates the use of sugarcane bagasse (SB) as an effective co-substrate due to its high C/N ratio and high VS content to improve the anaerobic co-digestion process with oily-biological sludge. The sugarcane bagasse also helps to delay the toxicity effect of the methane bacteria. Batch anaerobic co-digestion of oily-biological sludge was conducted with sugarcane bagasse as a co-substrate in twelve reactors with two-liter capacity, each under mesophilic conditions. The interaction effect of a C/N ratio of 20-30 and a VS co-substrate/VS inoculum ratio of 0.06-0.18 on the methane yield (mL CH4/g VSremoved) was investigated. Before the anaerobic digestion, thermochemical pre-treatment of the inoculum and co-substrate was conducted using sodium hydroxide to balance their acidic nature and provide a suitable pH environment for methane bacteria. Design and optimization for the mixing ratios were carried out by central composite design-response surface methodology (CCD-RSM). The highest predicted methane yield was found to be 63.52 mL CH4/g VSremoved, under optimum conditions (C/N ratio of 30 and co-substrate/inoculum ratio of 0.18).
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Duong TH, Grolle K, Nga TTV, Zeeman G, Temmink H, van Eekert M. Protein hydrolysis and fermentation under methanogenic and acidifying conditions. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:254. [PMID: 31673289 PMCID: PMC6815036 DOI: 10.1186/s13068-019-1592-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Many kinds of wastewaters contain appreciable quantities of protein. Anaerobic processes are suitable for the treatment of wastewater high in organics to achieve pollution control and recovery of energy as methane and hydrogen, or intermediates for production of biofuels and valuable biochemicals. A distinction between protein hydrolysis and amino acid fermentation, especially for dissolved proteins, is needed to target which one is truly rate-limiting and to effectively harvest bioproducts during anaerobic conversion of these wastewaters. This study explored mesophilic anaerobic hydrolysis and amino acid fermentation of gelatine, as a model for dissolved proteins, at pH 7 and at pH 5. RESULTS The results showed that at pH 7, protein hydrolysis (first-order rate of 0.15 h-1) was approximately 5 times faster than acidification of the hydrolysis products (first-order rate of 0.03 h-1), implying that not hydrolysis but acidification was the rate-limiting step in anaerobic dissolved protein degradation. This was confirmed by (temporary) accumulation of amino acids. Nineteen different amino acids were detected during the first 8 incubation hours of gelatine at neutral pH and the total chemical oxygen demand (COD) of these 19 amino acids was up to approximately 40% of the COD of the gelatine that was added. Protein hydrolysis at pH 5 was 2-25 times slower than at pH 7. Shifting the initial pH from neutral to acidic conditions (pH 5) inhibited protein degradation and changed the volatile fatty acids (VFA) product profile. Furthermore, the presence or absence of methanogenic activity did not affect the rates of protein hydrolysis and acidification. CONCLUSIONS The findings in this study can help to set a suitable solid retention time to accomplish anaerobic degradation of protein-rich wastewaters in continuous reactor systems. For example, if the target is harvesting VFAs, methanogens can be washed-out for a shorter retention time while amino acid fermentation, instead of hydrolysis as assumed previously, will govern the design and solutions to improve the system dealing with dissolved proteins.
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Affiliation(s)
- Thu Hang Duong
- Department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
- Faculty of Environmental Engineering, National University of Civil Engineering, 55 Giai Phong, Hanoi, Vietnam
| | - Katja Grolle
- Department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Tran Thi Viet Nga
- Faculty of Environmental Engineering, National University of Civil Engineering, 55 Giai Phong, Hanoi, Vietnam
| | - Grietje Zeeman
- Department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
- LeAF BV, PO Box 500, 6700 AM Wageningen, The Netherlands
| | - Hardy Temmink
- Department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Miriam van Eekert
- Department of Environmental Technology, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
- LeAF BV, PO Box 500, 6700 AM Wageningen, The Netherlands
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Xu R, Zhang K, Liu P, Khan A, Xiong J, Tian F, Li X. A critical review on the interaction of substrate nutrient balance and microbial community structure and function in anaerobic co-digestion. BIORESOURCE TECHNOLOGY 2018; 247:1119-1127. [PMID: 28958888 DOI: 10.1016/j.biortech.2017.09.095] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 06/07/2023]
Abstract
Anaerobic co-digestion generally results in a higher yield of biogas than mono-digestion, hence co-digestion has become a topic of general interest in recent studies of anaerobic digestion. Compared with mono-digestion, co-digestion utilizes multiple substrates. The balance of substrate nutrient in co-digestion comprises better adjustments of C/N ratio, pH, moisture, trace elements, and dilution of toxic substances. All of these changes could result in positive shifts in microbial community structure and function in the digestion processes and consequent augmentation of biogas production. Nevertheless, there have been few reviews on the interaction of nutrient and microbial community in co-digestions. The objective of this review is to investigate recent achievements and perspectives on the interaction of substrate nutrient balance and microbial community structure and function. This may provide valuable information on the optimization of combinations of substrates and prediction of bioreactor performance.
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Affiliation(s)
- Rong Xu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China
| | - Kai Zhang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China
| | - Pu Liu
- Department of Development Biology Sciences, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China
| | - Aman Khan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China
| | - Jian Xiong
- Wuhan Optics Valley Bluefire New Energy Co., Ltd, Fozulingsanlu Wuhan East Lake Development Zone #29, Wuhan, Hubei 430205, People's Republic of China
| | - Fake Tian
- Wuhan Optics Valley Bluefire New Energy Co., Ltd, Fozulingsanlu Wuhan East Lake Development Zone #29, Wuhan, Hubei 430205, People's Republic of China
| | - Xiangkai Li
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshui South Road #222, Lanzhou, Gansu 730000, People's Republic of China.
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