Editorial

2 pages, 121 KiB

Open AccessEditorial

by Liang Yu

Fermentation 2024, 10(1), 61; https://doi.org/10.3390/fermentation10010061 - 15 Jan 2024

Viewed by 898

As we conclude this Special Edition of “Energy Converter: Anaerobic Digestion”, a lingering sense of both achievement and anticipation accompanies us [...] Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

Research

Jump to: Editorial, Review

14 pages, 3012 KiB

Open AccessArticle

Layer Inoculation as a New Technology to Resist Volatile Fatty Acid Inhibition during Solid-State Anaerobic Digestion: Methane Yield Performance and Microbial Responses

by Xingliang Gao, Zhuowu Li, Keqiang Zhang, Dewang Kong, Wenxuan Gao, Junfeng Liang, Fuyuan Liu and Lianzhu Du

Fermentation 2023, 9(6), 535; https://doi.org/10.3390/fermentation9060535 - 31 May 2023

Cited by 3 | Viewed by 962

Abstract

Solid-state anaerobic digestion is easily inhibited by high volatile fatty acid induced by high total solids, although it is a promising technology. Previous studies on volatile fatty acid inhibition mainly focused on total solid content, co-digestion substrates, and external additives. The present study [...] Read more.

Solid-state anaerobic digestion is easily inhibited by high volatile fatty acid induced by high total solids, although it is a promising technology. Previous studies on volatile fatty acid inhibition mainly focused on total solid content, co-digestion substrates, and external additives. The present study proposed a new inoculation method named layer inoculation and compared it to premixing inoculation in the solid-state anaerobic digestion of pig manure and maize straw. The results showed that the cumulative CH₄ yields from layer inoculation (211.5 mL/g-VS) were 5.64 times more than premixing inoculation (37.5 mL/g-VS) under a low inoculation ratio (25%), with the values of total volatile fatty acid being greater than 30.0 mg/g. The concentrations of total VFAs and acetic acid from layer inoculation decreased dramatically during days 18–43. Layer inoculation also showed wider specific methane yield peaks and shorter startup times than premixing inoculation. Methanosphaerula and Methanothrix were the most dominant genera, while the genus Methanosphaerula did not correlate with volatile fatty acids, pH, or total ammonia nitrogen. The hydrogenotrophic methanogen pathway was predominant during solid-state anaerobic digestion; the shift from hydrogenotrophic to acetoclastic occurred in premixing inoculation, and it was stable in layer inoculation (61.20–68.88%). Overall, layer inoculation can effectively enhance methane production under high volatile fatty acid concentrations compared with premixing inoculation. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

19 pages, 1488 KiB

Open AccessArticle

Mesophilic, Anaerobic Digestion in a Full-Scale, Commercial Biogas Reactor Kills Seeds More Efficiently than Lab-Scale Systems

by Juliane Hahn, Paula Renate Westerman, Bärbel Gerowitt and Monika Heiermann

Fermentation 2023, 9(5), 481; https://doi.org/10.3390/fermentation9050481 - 17 May 2023

Viewed by 1027

Abstract

When plant biomass is anaerobically digested, seeds may survive the energy production process and contaminate the digestate. Hard-seeded (HS), i.e., physically dormant, species were found to be difficult to inactivate. Here, we aimed to verify this finding from lab-scale experimental reactors (ERs) in [...] Read more.

When plant biomass is anaerobically digested, seeds may survive the energy production process and contaminate the digestate. Hard-seeded (HS), i.e., physically dormant, species were found to be difficult to inactivate. Here, we aimed to verify this finding from lab-scale experimental reactors (ERs) in a full-scale commercial reactor (CR). In addition, we tested seed survival in a pH-buffered water bath (WB). Seeds were exposed to CR, ER and WB treatments at 42 °C for a maximum of 36 days. The viability of seeds was checked by measuring germination and response to tetrazolium staining and modeled as a function of exposure time using a dose–response approach. CR killed seeds more effectively than ER and WB treatments. The non-HS reference species, Chenopodium album, was completely inactivated by all treatments. Responses of the HS species ranged from complete inactivation to complete insensitivity. The most resistant was Malva sylvestris. The least resistant species were inactivated mainly by temperature, while additional mortality factors were effective in the more resistant species. We concluded that mesophilic AD in CRs can reduce the risk of seed contamination in the digestate for non-HS but not for HS species. Moreover, WB treatments seem suitable to estimate the minimum mortality of non-HS species in CR. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

14 pages, 2585 KiB

Open AccessArticle

Effects of Metal and Metal Ion on Biomethane Productivity during Anaerobic Digestion of Dairy Manure

by Liang Yu, Do-Gyun Kim, Ping Ai, Hairong Yuan, Jingwei Ma, Quanbao Zhao and Shulin Chen

Fermentation 2023, 9(3), 262; https://doi.org/10.3390/fermentation9030262 - 06 Mar 2023

Cited by 2 | Viewed by 1264

Abstract

To overcome major limiting factors of microbial processes in anaerobic digestion (AD), metal and metal ions have been extensively studied. However, there is confusion about the effects of metals and metal ions on biomethane productivity in previous research. In this study, Zn and [...] Read more.

To overcome major limiting factors of microbial processes in anaerobic digestion (AD), metal and metal ions have been extensively studied. However, there is confusion about the effects of metals and metal ions on biomethane productivity in previous research. In this study, Zn and Zn²⁺ were selected as representatives of metals and metal ions, respectively, to investigate the effects on biomethane productivity. After the metals and metal ions at different concentrations were added to the batch AD experiments under the same mesophilic conditions, a Zn dose of 1 g/L and a Zn²⁺ dose of 4 mg/L were found to cause the highest biomethane production, respectively. The results indicate that metal (Zn) and metal ion (Zn²⁺) have different mechanisms to improve AD performance. There may be two possible explanations. To act as conductive materials in interspecies electron transfer (IET), relatively high doses of metals (e.g., 1 g/L of Zn, 10 g/L of Fe) are needed to bridge the electron transfer from syntrophic bacteria to methanogenic archaea in the AD process. As essential mineral nutrients, the AD system requires relatively low doses of metal ions (e.g., 4 mg/L of Zn²⁺, 5 mg/L of Fe²⁺) to supplement the component of various enzymes that catalyze anaerobic reactions and transformations. This research will provide clear insight for selecting appropriate amounts of metals or metal ions to enhance biomethane productivity for industrial AD processes. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

17 pages, 2479 KiB

Open AccessArticle

The Effects of Nanoparticles- Zerovalent Iron on Sustainable Biomethane Production through Co-Digestion of Olive Mill Wastewater and Chicken Manure

by Khalideh Al Bkoor Alrawashdeh, Kamel K. Al-Zboon, Jalal A. Al-Tabbal, La’aly A. AL-Samrraie, Abeer Al Bsoul, Rebhi A. Damseh, Ayat Khasawneh, Yasser Dessouky, Kareem Tonbol, Bassma M. Ali and Elen E. Youssef

Fermentation 2023, 9(2), 183; https://doi.org/10.3390/fermentation9020183 - 17 Feb 2023

Cited by 3 | Viewed by 1733

Abstract

The impacts of nanoparticles-zerovalent iron (NP-ZVI) on anaerobic co-digestion (AcoD) were assessed. The production of biogas and methane (CH₄), as well as the removal efficiency of volatile solids (VS) and contaminants were investigated in the AcoD of chicken manure (CM) and [...] Read more.

The impacts of nanoparticles-zerovalent iron (NP-ZVI) on anaerobic co-digestion (AcoD) were assessed. The production of biogas and methane (CH₄), as well as the removal efficiency of volatile solids (VS) and contaminants were investigated in the AcoD of chicken manure (CM) and olive mill wastewater (OMWW) with the addition of NP-ZVI at different concentrations (10–50 mg/g VS) and different sizes resulting from various mixing volume ratios (MVR) of NaBH₄:FeSO₄.7H₂O. The results show that NP-ZVI ≤ 30 mg/g VS at MVR-2:1, MVR-4:1, and MVR-6:1 improves the AcoD. In contrast to 40–50 mg/g VS of NP-ZVI, which caused an inhibitory impact in all of the AcoD stages, as well as a decrease in the contaminant’s removal efficiency, the concentration of 10–30 mg NP-ZVI/g VS at MVR-4:1 achieved a maximum improvement of CH₄ by 21.09%, 20.32%, and 22.87%, respectively, and improved the biogas by 48.14%, 55.0%, and 80.09%, respectively, vs. the 0 additives. Supplementing AcoD with NP-ZVI at a concentration of 30 mg/g VS at MVR-4:1 resulted in maximum enhancement of the contaminant removal efficiency, with a total oxygen demand (TCOD) of up to 73.99%, turbidity up to 79.07%, color up to 53.41%, total solid (TS) up to 59.57%, and volatile solid (VS) up to 74.42%. It also improved the hydrolysis and acidification percentages by up to 86.67% and 51.3%, respectively. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Graphical abstract

24 pages, 8236 KiB

Open AccessArticle

Low-Grade Syngas Biomethanation in Continuous Reactors with Respect to Gas–Liquid Mass Transfer and Reactor Start-Up Strategy

by Bingyi Jiang, Dongming Zhang, Xiao Hu, Ulf Söderlind, Gabriela Paladino, Shiromini Gamage, Erik Hedenström, Wennan Zhang, Juan Arrigoni, Anders Lundgren, Malin Tuvesson and Chunjiang Yu

Fermentation 2023, 9(1), 38; https://doi.org/10.3390/fermentation9010038 - 31 Dec 2022

Cited by 3 | Viewed by 1769

Abstract

In order to utilize a wider range of low-grade syngas, the syngas biomethanation was studied in this work with respect to the gas–liquid mass transfer and the reactor start-up strategy. Two reactors, a continuous stirred tank (CSTR) and a bubble column with gas [...] Read more.

In order to utilize a wider range of low-grade syngas, the syngas biomethanation was studied in this work with respect to the gas–liquid mass transfer and the reactor start-up strategy. Two reactors, a continuous stirred tank (CSTR) and a bubble column with gas recirculation (BCR-C), were used in the experiment by feeding an artificial syngas of 20% H₂, 50% CO, and 30% CO₂ into the reactors at 55 °C. The results showed that the CH₄ productivity was slightly increased by reducing the gas retention time (GRT), but was significantly improved by increasing the stirring speed in the CSTR and the gas circulation rate in the BCR-C. The best syngas biomethanation performance of the CSTR with a CH₄ productivity of 22.20 mmol·L_r⁻¹·day⁻¹ and a yield of 49.01% was achieved at a GRT of 0.833 h and a stirring speed of 300 rpm, while for the BCR-C, the best performance with a CH₄ productivity of 61.96 mmol·L_r⁻¹·day⁻¹ and a yield of 87.57% was achieved at a GRT of 0.625 h and a gas circulation rate of 40 L·L_r⁻¹·h⁻¹. The gas–liquid mass transfer capability provided by gas circulation is far superior to mechanical stirring, leading to a much better performance of low-grade syngas biomethanation in the BCR-C. Feeding H₂/CO₂ during the startup stage of the reactor can effectively stimulate the growth and metabolism of microorganisms, and create a better metabolic environment for subsequent low-grade syngas biomethanation. In addition, during the thermophilic biomethanation of syngas, Methanothermobacter is the dominant genus. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

24 pages, 3556 KiB

Open AccessArticle

Characterization of Biofilm Microbiome Formation Developed on Novel 3D-Printed Zeolite Biocarriers during Aerobic and Anaerobic Digestion Processes

by Afroditi G. Chioti, Vasiliki Tsioni, Stefanos Patsatzis, Eirini Filidou, Dimitra Banti, Petros Samaras, Eleni Anna Economou, Eleni Kostopoulou and Themistoklis Sfetsas

Fermentation 2022, 8(12), 746; https://doi.org/10.3390/fermentation8120746 - 15 Dec 2022

Cited by 4 | Viewed by 2264

Abstract

Background: Aerobic or anaerobic digestion is involved in treating agricultural and municipal waste, and the addition of biocarriers has been proven to improve them further. We synthesized novel biocarriers utilizing zeolites and different inorganic binders and compared their efficiency with commercially available biocarriers [...] Read more.

Background: Aerobic or anaerobic digestion is involved in treating agricultural and municipal waste, and the addition of biocarriers has been proven to improve them further. We synthesized novel biocarriers utilizing zeolites and different inorganic binders and compared their efficiency with commercially available biocarriers in aerobic and anaerobic digestion systems. Methods: We examined BMP and several physicochemical parameters to characterize the efficiency of novel biocarriers on both systems. We also determined the SMP and EPS content of synthesized biofilm and measured the adherence and size of the forming biofilm. Finally, we characterized the samples by 16S rRNA sequencing to determine the crucial microbial communities involved. Results: Evaluating BMP results, ZSM-5 zeolite with bentonite binder emerged, whereas ZSM-5 zeolite with halloysite nanotubes binder stood out in the wastewater treatment experiment. Twice the relative frequencies of archaea were found on novel biocarriers after being placed in AD batch reactors, and >50% frequencies of Proteobacteria after being placed in WWT reactors, compared to commercial ones. Conclusions: The newly synthesized biocarriers were not only equally efficient with the commercially available ones, but some were even superior as they greatly enhanced aerobic or anaerobic digestion and showed strong biofilm formation and unique microbiome signatures. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

9 pages, 564 KiB

Open AccessArticle

Methane Production of Pistia Stratiotes as a Single Substrate and as a Co-Substrate with Dairy Cow Manure

by Sutaryo Sutaryo, Aldila Nugrahaini Sempana, Rifo Martio Mulya, Dian Sulistyaningrum, Mochamad Sofyan Ali, Rafi Ihsa Damarjati, Endang Purbowati, Retno Adiwinarti and Agung Purnomoadi

Fermentation 2022, 8(12), 736; https://doi.org/10.3390/fermentation8120736 - 13 Dec 2022

Cited by 3 | Viewed by 1574

Abstract

Mono anaerobic digestion (AD) of dairy cow manure (DCM) is constrained by high moisture, ash and crude fibre content. Anaerobic co-digestion DCM and other biomass is one of the methods to overcome this drawback. This study aimed to evaluate: methane production from different [...] Read more.

Mono anaerobic digestion (AD) of dairy cow manure (DCM) is constrained by high moisture, ash and crude fibre content. Anaerobic co-digestion DCM and other biomass is one of the methods to overcome this drawback. This study aimed to evaluate: methane production from different parts of Pistia stratiotes (PS), methane production from the mixed substrate of PS and DCM in different proportions of PS in terms of volatile solids (VS) (0%, 7.99%, 14.91%, and 20.94%) using continuous digesters, and the potency of biogas yield from the digested slurry. Methane production from the whole plant, shoot system, and root of PS was 405.68, 416.82, and 326.42 L/kg VS, respectively. The highest methane production was obtained from the shoot system because that part contained higher crude protein and hemicellulose contents. Utilization of PS as a co-substrate for AD of the DCM can increase methane production by 28.65–56.98% compared to the control digester. No effect on pH, total ammonia nitrogen and total volatile fatty acid indicated that PS was suitable as a co-substrate of DCM and can significantly increase methane yield of the mixed substrate. AD of digested slurries showed that to recover the biogas production from the mixed substrate, the post-digestion treatment should be applied before the slurries are used as organic fertilizer. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

12 pages, 1328 KiB

Open AccessArticle

Anaerobic Digestion of Cereal Rye Cover Crop

by Liangcheng Yang, Lucas D. Lamont, John C. Sedbrook, Nicholas J. Heller and David E. Kopsell

Fermentation 2022, 8(11), 617; https://doi.org/10.3390/fermentation8110617 - 09 Nov 2022

Cited by 4 | Viewed by 1610

Abstract

The rapid growth of cover crop planting area in the U.S. helps with erosion control, soil health, control of greenhouse gases, and also provides abundant biomass for the production of bioenergy and bioproducts. Given the cover crops’ compositional heterogeneity and variability, a tolerate [...] Read more.

The rapid growth of cover crop planting area in the U.S. helps with erosion control, soil health, control of greenhouse gases, and also provides abundant biomass for the production of bioenergy and bioproducts. Given the cover crops’ compositional heterogeneity and variability, a tolerate platform technology such as anaerobic digestion (AD) is preferred but has not been widely used for cover crop biorefining. This study evaluated the biogas and methane yields from six cereal rye (Secale cereale L.) cover crops grown in the Midwest, using both bench- and pilot-scale anaerobic digesters. The effects of two critical factors, the total solids (TS) content and ensiling, on digester performance were also investigated. Methane yields of 174.79–225.23 L/kg-VS were obtained from the bench-scale tests using cereal rye as the mono feedstock. The pilot-scale test with no pH adjustment showed a slightly higher methane yield. Ensiling increased the methane yield by 23.08% at 6% TS, but disturbed AD at 8% TS, and failed AD at 10% and 15% TS. Findings from this study would help farmers and the biorefining industry to determine the baseline performance and revenue of cereal rye AD and to develop strategies for process control and optimization. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

13 pages, 2958 KiB

Open AccessArticle

Addition of Conductive Materials to Support Syntrophic Microorganisms in Anaerobic Digestion

by Roger König, Maurizio Cuomo, Elisa Pianta, Antoine Buetti, Federica Mauri, Matteo Tanadini and Pamela Principi

Fermentation 2022, 8(8), 354; https://doi.org/10.3390/fermentation8080354 - 26 Jul 2022

Cited by 8 | Viewed by 1989

Abstract

Syntrophy and interspecies electron transfer among different microbial groups occurs in anaerobic digestion, and many papers recently reported their positive effect on biogas and methane production. In this paper, we present the results on the effect of conductive material, i.e., graphene, PAC and [...] Read more.

Syntrophy and interspecies electron transfer among different microbial groups occurs in anaerobic digestion, and many papers recently reported their positive effect on biogas and methane production. In this paper, we present the results on the effect of conductive material, i.e., graphene, PAC and biochar addition in 3.5 L batch experiments, analyzing the biogas production curve. A peculiar curve pattern occurred in the presence of conductive materials. Compared to the respective controls, the addition of graphene produced a biogas surplus of 33%, PAC 20% and biochar 8%. Microbial community molecular analysis showed that syntrophic microorganisms present in the inoculum were stimulated by the conductive material addition. Graphene also appears to promote an interspecies electron transfer between Geobacter sp. and ca. Methanofastidiosum. This paper contributes to the understanding of the DIET-related microbial community dynamic in the presence of graphene and PAC, which could be exploited to optimize biogas and methane production in real-scale applications. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

19 pages, 5209 KiB

Open AccessArticle

Effect of Pretreatment by Freeze Vacuum Drying on Solid-State Anaerobic Digestion of Corn Straw

by Zhen Liu, Jinzhi Huang, Yiqing Yao, Mengyi Wang and Anjie Li

Fermentation 2022, 8(6), 259; https://doi.org/10.3390/fermentation8060259 - 30 May 2022

Cited by 3 | Viewed by 2188

Abstract

As a common agricultural waste, corn straw (CS) has a refractory structure, which is not conducive to anaerobic digestion (AD). Appropriate pretreatment is crucial for addressing this problem. Thus, freeze vacuum drying (FVD) was proposed. In this study, fresh CS (F-CS) pretreated (5 [...] Read more.

As a common agricultural waste, corn straw (CS) has a refractory structure, which is not conducive to anaerobic digestion (AD). Appropriate pretreatment is crucial for addressing this problem. Thus, freeze vacuum drying (FVD) was proposed. In this study, fresh CS (F-CS) pretreated (5 h, −40 °C) by FVD and naturally dried CS (D-CS) were compared. Differences in substrate surface structure and nutrient composition were first investigated. Results show that a loose and porous structure, crystallinity, and broken chemical bonds, as well as higher proportions of VS, C, N, cellulose, hemicellulose, and crude proteins in F-CS show a potential for methane production. Besides, process performance and stability were also examined in both high (4, VS basis) and low (1, VS basis) S/I ratio AD. A higher degradation ratio of hemicellulose as well as richer dissolved microbial metabolites, coenzymes, tyrosine-like proteins, and hydrolysis rate of particulate organic matter in the F-CS system enhanced the efficiency of methane conversion. The cumulative methane yield increased from 169.66 (D-CS) to 209.97 (F-CS) mL/gVS in the high S/I ratio system (p = 0.02 < 0.05), and 156.97 to 171.89 mL/gVS in the low S/I ratio system. Additionally, 16S-rRNA-gene-based analysis was performed. Interestingly, the coordination of key bacteria (Clostridium_sensu_stricto_1, Bacillus, Terrisporobacter, Clostridium_sensu_stricto_7, Thermoclostrium, UCG-012, and HN-HF0106) was more active. Poorer Methanosarcina and Methanomassiliicoccus as well as richer Methanobrevibacter and Methanoculleus stimulated the co-relationship of key archaea with diverse methanogenesis pathways. This study aims to verify the positive effect of FVD pretreatment on AD of CS, so as to provide a reference for applications in waste management. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

Review

Jump to: Editorial, Research

33 pages, 8471 KiB

Open AccessReview

Bioelectrochemical Systems (BES) for Biomethane Production—Review

by Noémi N. Horváth-Gönczi, Zoltán Bagi, Márk Szuhaj, Gábor Rákhely and Kornél L. Kovács

Fermentation 2023, 9(7), 610; https://doi.org/10.3390/fermentation9070610 - 28 Jun 2023

Cited by 4 | Viewed by 1900

Abstract

Bioelectrochemical systems (BESs) have great potential in renewable energy production technologies. BES can generate electricity via Microbial Fuel Cell (MFC) or use electric current to synthesize valuable commodities in Microbial Electrolysis Cells (MECs). Various reactor configurations and operational protocols are increasing rapidly, although [...] Read more.

Bioelectrochemical systems (BESs) have great potential in renewable energy production technologies. BES can generate electricity via Microbial Fuel Cell (MFC) or use electric current to synthesize valuable commodities in Microbial Electrolysis Cells (MECs). Various reactor configurations and operational protocols are increasing rapidly, although industrial-scale operation still faces difficulties. This article reviews the recent BES related to literature, with special attention to electrosynthesis and the most promising reactor configurations. We also attempted to clarify the numerous definitions proposed for BESs. The main components of BES are highlighted. Although the comparison of the various fermentation systems is, we collected useful and generally applicable operational parameters to be used for comparative studies. A brief overview links the appropriate microbes to the optimal reactor design. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Graphical abstract

25 pages, 2130 KiB

Open AccessReview

Casting Light on the Micro-Organisms in Digestate: Diversity and Untapped Potential

by Ashira Roopnarain, Muyiwa Ajoke Akindolire, Haripriya Rama and Busiswa Ndaba

Fermentation 2023, 9(2), 160; https://doi.org/10.3390/fermentation9020160 - 07 Feb 2023

Viewed by 1871

Abstract

Anaerobic digestion (AD) is an established process for waste conversion to bioenergy. However, for the AD process to be viable, it is imperative that all products be adequately valorized to maximize the benefits associated with the technology and in turn promote economic feasibility [...] Read more.

Anaerobic digestion (AD) is an established process for waste conversion to bioenergy. However, for the AD process to be viable, it is imperative that all products be adequately valorized to maximize the benefits associated with the technology and in turn promote economic feasibility and technology uptake. Digestate is a byproduct of the AD process that is oftentimes overshadowed by the primary product, biogas, however the potential of digestate is vast. Digestate is composed of undigested organic matter, inorganic matter, and microorganisms. Whilst digestate has frequently been utilized as a soil amendment due to its abundance of readily available plant nutrients, the microbial content of digestate is oftentimes neglected or undermined. The array of microbes prevalent in digestate may contribute to expanding its potential applications. This microbial composition is shaped by several factors including resident microbial communities in inoculum and feedstock, feedstock composition, temperature of the AD system, AD additives and augmenting agents as well as post-treatment strategies, amongst others. Hence, it is hypothesized that digestate microbial content can be manipulated to target particular downstream applications by altering the above-mentioned factors. In so doing, the value of the produced digestate may be improved, which may even lead to digestate becoming the most lucrative product of the AD process. This review provides a holistic overview of the factors influencing the microbial community structure of digestate, the microorganisms in digestate from diverse AD systems and the associated microbial functionality as well as the potential applications of the digestate from a perspective of the resident microflora. The aim of the paper is to highlight the vast potential of microorganisms in digestate so as to broaden its applicability and value. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Energy Converter: Anaerobic Digestion

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Related Special Issue

Published Papers (13 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI