Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation

A special issue of Fermentation (ISSN 2311-5637). This special issue belongs to the section "Industrial Fermentation".

Deadline for manuscript submissions: closed (31 March 2022) | Viewed by 38593

Special Issue Editors

Environmental Engineering and Water Technology, Institute of Water Education, Westvest 7, 2611 AX Delft, The Netherlands
Interests: development of bioprocesses for air; water and soil remediation
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Maria Carmen Veiga
E-Mail Website
Guest Editor
Department of Chemical Engineering, Faculty of Sciences and Center for Advanced Scientific Research (CICA), University of La Coruña, 15008 La Coruña, Spain
Interests: bioremendiation
Department of Chemical Engineering, Faculty of Sciences, University of La Coruña, La Coruña, Spain
Interests: waste gas treatment; wastewater treatment; fermentation technology; biodegradation; bioconversion; biofuels; biorefinery
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

In recent years, the optimization of bioprocesses for the removal of pollutants from industrial biogenic gas emissions, waste and wastewater has been the focus of intensive research. Recently developed technologies not only aim to remove such pollutants, but also to valorize them, whenever possible, through their bioconversion into useful added value products. In this domain of progressive research, lab-, pilot-, and demonstration-scale studies have been dealing with the fermentation of biogenic gases (e.g., CO2, CO, CH4), waste or wastewater to produce a range of biofuels and valuable products, based on the activity of pure or mixed cultures of native or recombinant an/aerobic bacteria, algae, or yeasts as biocatalysts. Waste can also be converted to syngas, which can subsequently be fermented as well. A broad range of bioproducts can be obtained, e.g., (bio)ethanol and higher alcohols, short and medium chain fatty acids, biopolymers, microbial oils and several other platform chemicals and products, to mention only a few examples. This environmentally friendly biorefinery approach addresses the need to build modern societies according to a circular economy concept and yields products of commercial interest. This Special Issue focusses on recent trends in this domain and will consider both research as well as review papers. For review papers, the authors should provide, in their cover letter, a list of recent publications (up to ten) of their own, highlighting their expertise in the field.

Dr. Eldon R. Rene
Prof. Dr. Maria Carmen Veiga
Prof. Dr. Christian Kennes
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Acetogenic bacteria
  • Algae
  • Biorefinery
  • Biofuels
  • Biogas
  • Biopolymers
  • Biomass
  • Bioproducts
  • Chain elongation
  • FAME
  • Greenhouse gases
  • Lignocellulose
  • Steel industry
  • Syngas
  • Synthetic biology
  • Yeasts

Published Papers (14 papers)

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Editorial

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5 pages, 211 KiB  
Editorial
Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation
Fermentation 2022, 8(8), 347; https://doi.org/10.3390/fermentation8080347 - 23 Jul 2022
Cited by 2 | Viewed by 1198
Abstract
In recent years, the optimization of bioprocesses for the removal of pollutants from industrial biogenic gas emissions, waste and wastewater has been the focus of intensive research. Recently developed technologies not only aim to remove such pollutants, but also to valorize them, whenever [...] Read more.
In recent years, the optimization of bioprocesses for the removal of pollutants from industrial biogenic gas emissions, waste and wastewater has been the focus of intensive research. Recently developed technologies not only aim to remove such pollutants, but also to valorize them, whenever possible, through their bioconversion into useful added-value products. In this domain of progressive research, lab-, pilot-, and demonstration-scale studies are dealing with the fermentation of biogenic gases (e.g., CO2, CO, and CH4), waste or wastewater to produce a range of biofuels and valuable products, based on the activity of pure or mixed cultures of native or recombinant aerobic and anaerobic bacteria, algae, or yeasts as biocatalysts. Waste can also be converted to syngas, which can subsequently be fermented as well. A broad range of bioproducts can be obtained, e.g., biofuels and several other platform chemicals and products. This environmentally-friendly biorefinery approach addresses the need to build modern societies according to the concept of a circular economy, and yields products of commercial interest. Different examples of such approaches are described in this collection of scientific reports. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)

Research

Jump to: Editorial

21 pages, 3860 KiB  
Article
Evaluation of Lignocellulosic Wastewater Valorization with the Oleaginous Yeasts R. kratochvilovae EXF7516 and C. oleaginosum ATCC 20509
Fermentation 2022, 8(5), 204; https://doi.org/10.3390/fermentation8050204 - 30 Apr 2022
Cited by 6 | Viewed by 2916
Abstract
During the conversion of lignocellulose, phenolic wastewaters are generated. Therefore, researchers have investigated wastewater valorization processes in which these pollutants are converted to chemicals, i.e., lipids. However, wastewaters are lean feedstocks, so these valorization processes in research typically require the addition of large [...] Read more.
During the conversion of lignocellulose, phenolic wastewaters are generated. Therefore, researchers have investigated wastewater valorization processes in which these pollutants are converted to chemicals, i.e., lipids. However, wastewaters are lean feedstocks, so these valorization processes in research typically require the addition of large quantities of sugars and sterilization, which increase costs. This paper investigates a repeated batch fermentation strategy with Rhodotorula kratochvilovae EXF7516 and Cutaneotrichosporon oleaginosum ATCC 20509, without these requirements. The pollutant removal and its conversion to microbial oil were evaluated. Because of the presence of non-monomeric substrates, the ligninolytic enzyme activity was also investigated. The repeated batch fermentation strategy was successful, as more lipids accumulated every cycle, up to a total of 5.4 g/L (23% cell dry weight). In addition, the yeasts consumed up to 87% of monomeric substrates, i.e., sugars, aromatics, and organics acids, and up to 23% of non-monomeric substrates, i.e., partially degraded xylan, lignin, cellulose. Interestingly, lipid production was only observed during the harvest phase of each cycle, as the cells experienced stress, possibly due to oxygen limitation. This work presents the first results on the feasibility of valorizing non-sterilized lignocellulosic wastewater with R. kratochvilovae and C. oleaginosum using a cost-effective repeated batch strategy. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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15 pages, 3842 KiB  
Article
Cultivation of Microalgae in Unsterile Malting Effluent for Biomass Production and Lipid Productivity Improvement
Fermentation 2022, 8(4), 186; https://doi.org/10.3390/fermentation8040186 - 14 Apr 2022
Cited by 7 | Viewed by 2477
Abstract
Microalgae have the potential to grow in nutrient-rich environments and have the ability to accumulate nutrients from wastewater. The nutrients in malting wastewater are ideal for microalgae cultivation. However, there is limited published work on the growth characteristics of freshwater microalgae grown in [...] Read more.
Microalgae have the potential to grow in nutrient-rich environments and have the ability to accumulate nutrients from wastewater. The nutrients in malting wastewater are ideal for microalgae cultivation. However, there is limited published work on the growth characteristics of freshwater microalgae grown in malting effluent. This study examined the potential of diluted malting effluent for the growth of freshwater green algae Chlorella sp. and Chlamydomonas sp. isolated from northern Ontario and subsequent biomass and lipid production. Under the 18:6 h light/dark cultivation cycle, the highest cell number counted (540 × 104 cell·mL−1 on day 20) and total chlorophyll content were found in 50% diluted malting effluents for Chlorella sp., whereas the 70% dilution concentration was the most productive for Chlamydomonas (386 × 104 cell·mL−1 on day 16). The total lipid content was higher in the 50% dilution concentration of malting effluent in both Chlorella sp. (maximum 20.5%–minimum 11.5% of dry weight) and Chlamydomonas sp. (max 39.3%–min 25.9% of dry weight). These results emphasize the suitability of using unsterile diluted malting effluent for microalgae cultivation. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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15 pages, 2514 KiB  
Article
Establishing Mixotrophic Growth of Cupriavidus necator H16 on CO2 and Volatile Fatty Acids
Fermentation 2022, 8(3), 125; https://doi.org/10.3390/fermentation8030125 - 14 Mar 2022
Cited by 14 | Viewed by 4184
Abstract
The facultative chemolithoautotroph Cupriavidus necator H16 is able to grow aerobically either with organic substrates or H2 and CO2 s and it can accumulate large amounts of (up to 90%) poly (3-hydroxybutyrate), a polyhydroxyalkanoate (PHA) biopolymer. The ability of this organism [...] Read more.
The facultative chemolithoautotroph Cupriavidus necator H16 is able to grow aerobically either with organic substrates or H2 and CO2 s and it can accumulate large amounts of (up to 90%) poly (3-hydroxybutyrate), a polyhydroxyalkanoate (PHA) biopolymer. The ability of this organism to co-utilize volatile fatty acids (VFAs) and CO2 as sources of carbon under mixotrophic growth conditions was investigated and PHA production was monitored. PHA accumulation was assessed under aerobic conditions, with either individual VFAs or in mixtures, under three different conditions—with CO2 as additional carbon source, without CO2 and with CO2 and H2 as additional sources of carbon and energy. VFAs utilisation rates were slower in the presence of CO2. PHA production was significantly higher when cultures were grown mixotrophically and with H2 as an additional energy source compared to heterotrophic or mixotrophic growth conditions, without H2. Furthermore, a two-step VFA feeding regime was found to be the most effective method for PHA accumulation. It was used for PHA production mixotrophically using CO2, H2 and VFA mixture derived from an anaerobic digestor (AD). The data obtained demonstrated that process parameters need to be carefully monitored to avoid VFA toxicity and low product accumulation. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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16 pages, 1633 KiB  
Article
Pilot-Scale Anaerobic Treatment of Printing and Dyeing Wastewater and Performance Prediction Based on Support Vector Regression
Fermentation 2022, 8(3), 99; https://doi.org/10.3390/fermentation8030099 - 26 Feb 2022
Cited by 4 | Viewed by 2036
Abstract
Printing and dyeing wastewater is characterized with complex water quality and poor biodegradability. In this study, a pilot-scale anaerobic baffled reactor (ABR) with packing was verified to effectively degrade the complex organic pollutants in the wastewater through the hydrolysis and acidification of anaerobic [...] Read more.
Printing and dyeing wastewater is characterized with complex water quality and poor biodegradability. In this study, a pilot-scale anaerobic baffled reactor (ABR) with packing was verified to effectively degrade the complex organic pollutants in the wastewater through the hydrolysis and acidification of anaerobic microorganisms. At a hydraulic retention time (HRT) of 12 h and an organic loading rate (OLR) of 2.0–2.5 kg COD/(m3·d), the ABR stabilized the fluctuation range of pH and achieved an average colority removal rate of 10.5%, which provided favorable conditions for subsequent aerobic treatment. During the early operation period, the reactor increased the alkalinity of the wastewater; after 97 days of operation, the volatile fatty acid (VFA) content in the wastewater decreased. To demonstrate the suitability of the support vector regression (SVR) technology in predicting the performance of the reactor, two SVR algorithms with three kernel functions were employed to relate the chemical oxygen demand (COD) removal rate to its influencing factors, and the predictions of both the training and validation groups agreed with the measurements. The results obtained from this study can contribute to the design and optimal operation of the anaerobic treatment project of the industrial wastewater treatment plant. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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15 pages, 2071 KiB  
Article
Development of a Culture Medium for Microalgae Production Based on Minimal Processing of Oil Palm Biomass Ash
Fermentation 2022, 8(2), 55; https://doi.org/10.3390/fermentation8020055 - 27 Jan 2022
Cited by 3 | Viewed by 2537
Abstract
With the increasing participation of biomass in the world energy matrix, large amounts of ash are produced through combustion, resulting in the need to dispose of this waste to minimize the environmental impact. An alternative is to use ashes as phosphorus supplements in [...] Read more.
With the increasing participation of biomass in the world energy matrix, large amounts of ash are produced through combustion, resulting in the need to dispose of this waste to minimize the environmental impact. An alternative is to use ashes as phosphorus supplements in microalgae cultures. The present work describes the development and use of a balanced culture medium based on the minimal processing of oil palm biomass ash to cultivate Arthrospira platensis Paracas, Neochloris oleoabundans UTEX 1185, and Dunaliella salina SAG 184. The acid extraction process of phosphorus (P) was defined by evaluating the following parameters: temperature (20 to 70 °C), acid load (0.01 to 0.03 mols/g of ash) of HNO3, and liquid/solid ratio (50 to 150 mLg−1). The best efficiency of the extraction process was 97%. The use of HNO3 allowed for the production of an extract containing balanced amounts of N and P sources, the BAX medium (Biomass Ash Extract). This medium was efficient for cultivating the three microorganisms studied, reaching biomass concentrations of 2.03, 0.902, and 0.69 g/L or 84%, 82%, and 99% of the control concentrations for A. platensis, N. Oleoabundans, and D. salina, respectively. In a final scaling-up test, A. platensis showed productivity of 0.047 g L−1d−1 in a 120 L tank in a greenhouse. BAX can be an alternative nutrient medium for microalgae cultivation, especially in integration with biomass-fueled biorefineries. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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19 pages, 2018 KiB  
Article
Characteristics and Anaerobic Co-Digestion of Press Water from Wood Fuel Preparation and Digested Sewage Sludge
Fermentation 2022, 8(1), 37; https://doi.org/10.3390/fermentation8010037 - 17 Jan 2022
Cited by 3 | Viewed by 3188
Abstract
Technical drying of harvested wood fuels is heat and energy consuming, while natural pre-drying in the forest, e.g., in stacks or storage piles, is accompanied by energy losses through natural degradation processes. Dewatering of energy wood by mechanical pressing is an innovative method [...] Read more.
Technical drying of harvested wood fuels is heat and energy consuming, while natural pre-drying in the forest, e.g., in stacks or storage piles, is accompanied by energy losses through natural degradation processes. Dewatering of energy wood by mechanical pressing is an innovative method to reduce the moisture content prior to thermal drying while producing press waters (PW, also referred to as wood juice) as a by-product. To date, the characteristics and utilization potentials of PW are largely unknown. In this study, three different spruce- and poplar-based PW were analyzed for their characteristics such as dry matter (DM), organic dry matter (oDM) concentration, pH-value, element concentration or chemical compounds. Additionally, they were used for anaerobic digestion (AD) experiments with digested sewage sludge (DSS) serving as inoculum. The fresh matter-based DM concentrations of the PW were between 0.4 and 3.2%, while oDM concentrations were between 87 and 89%DM. The spruce-based PW were characterized by lower pH-values of approx. 4.4, while the poplar-based PW was measured at pH 8. In the AD experiments, DSS alone (blank variant) achieved a specific methane yield of 95 ± 26 mL/goDM, while the mixture of spruce-based PW and DSS achieved up to 160 ± 12 mL/goDM, respectively. With further research, PW from wood fuel preparation offer the potential to be a suitable co-substrate or supplement for AD processes. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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12 pages, 3009 KiB  
Article
pH-Based Control Strategies for the Nitrification of High-Ammonium Wastewaters
Fermentation 2021, 7(4), 319; https://doi.org/10.3390/fermentation7040319 - 19 Dec 2021
Cited by 2 | Viewed by 2223
Abstract
Aquatic nitrogen pollution is one of the most urgent environmental issues requiring prevention and mitigation. Large quantities of high-ammonium wastewaters are generated by several industrial sectors, such as fertilizer and anaerobic-digestion plants. Nitrification of these wastewaters is commonly carried out, either to remove [...] Read more.
Aquatic nitrogen pollution is one of the most urgent environmental issues requiring prevention and mitigation. Large quantities of high-ammonium wastewaters are generated by several industrial sectors, such as fertilizer and anaerobic-digestion plants. Nitrification of these wastewaters is commonly carried out, either to remove nitrogen or produce liquid fertilizers. Standard control methodologies for the efficient nitrification of high-ammonium wastewaters to produce liquid fertilizers have not yet been established and are still within their early stages of development. In this paper, novel pH-based control algorithms are presented that maintain operation at the microbial maximum reaction rate (υmax) in batch and continuous reactors. Complete conversion of ammonium to nitrate was achieved in a batch setup, and a conversion of 93% (±1%) was achieved in a continuously-stirred-tank-reactor. The unparalleled performance and affordability of the control schemes proposed offer a steppingstone to the future of sustainable fertilizer production. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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11 pages, 1489 KiB  
Article
A Method for WWTP Sludge Valorization through Hygienization by Electron Beam Treatment
Fermentation 2021, 7(4), 302; https://doi.org/10.3390/fermentation7040302 - 09 Dec 2021
Cited by 1 | Viewed by 1940
Abstract
This work reports on municipal sludge hygienization using electron beams. Three types of sewage sludge from two municipal wastewater treatment plants were tested: preliminary sludge with 4% TS, postflotation sludge with 2.5% TS and thickened preliminary sludge with 10% TS. The analysis of [...] Read more.
This work reports on municipal sludge hygienization using electron beams. Three types of sewage sludge from two municipal wastewater treatment plants were tested: preliminary sludge with 4% TS, postflotation sludge with 2.5% TS and thickened preliminary sludge with 10% TS. The analysis of reference samples demonstrated the presence of bacteria and helminths ova in all examined samples. For the study of hygienization, electron beams from two types of accelerators, linear (Elektronika 10/10) and single cavity (ILU-6), were applied. For each type of accelerator, different irradiation methods were used: irradiation in sealed polyethylene bags using conveyor and flow irradiation installation. Experiments showed that the doses necessary for the elimination of mentioned pathogens were 4 kGy for preliminary sludge, 4 kGy for postflotation sludge and 5.5 kGy for preliminary sludge. The differences between the amounts of initial pathogens in preliminary and thickened preliminary sludge were marginal. It is possible that the higher irradiation dose required to hygienize thickened sludge resulted from higher TS concentration. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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12 pages, 1636 KiB  
Article
Plant Biomass Production in Constructed Wetlands Treating Swine Wastewater in Tropical Climates
Fermentation 2021, 7(4), 296; https://doi.org/10.3390/fermentation7040296 - 02 Dec 2021
Cited by 8 | Viewed by 2773
Abstract
The production of both aboveground and belowground plant biomass in constructed wetlands (CW) is a poorly understood topic, although vegetation plays an important role in the process of pollutant removal from wastewater. The objective of this study was to evaluate the aboveground and [...] Read more.
The production of both aboveground and belowground plant biomass in constructed wetlands (CW) is a poorly understood topic, although vegetation plays an important role in the process of pollutant removal from wastewater. The objective of this study was to evaluate the aboveground and belowground biomass production of Typha latifolia and Canna hybrids in a large-scale constructed wetland treating swine wastewater in tropical climates. Parameters, such as temperature, DO, pH, COD, TSS, TN, TP, and TC, as well as destructive and non-destructive biomass, were evaluated. It was found that, despite the high concentrations of pollutants, the vegetation adapted easily and also grew healthily despite being exposed to high concentrations of pollutants from swine water. Although Typha latifolia (426 plants) produced fewer plants than Canna hybrids (582 plants), the higher biomass of the Typha latifolia species was slightly higher than that of Canna hybrids by 5%. On the other hand, the proximity of the water inlet to the system decreased the capacity for the development of a greater number of seedlings. As for the elimination of pollutants, after treatment in the constructed wetland, COD: 83.6 ± 16.9%; TSS: 82.2 ± 17.7%; TN: 94.4 ± 15.8%; TP: 82.4 ± 23.2%; and TC: 94.4 ± 4.4% were significantly reduced. These results show that wetlands constructed as tertiary systems for the treatment of swine wastewater produce a large amount of plant biomass that significantly helps to reduce the concentrations of pollutants present in this type of water in tropical areas. The use of these plants is recommended in future wetland designs to treat swine wastewater. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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15 pages, 1466 KiB  
Article
Effects of Lipase Addition, Hydrothermal Processing, Their Combination, and Co-Digestion with Crude Glycerol on Food Waste Anaerobic Digestion
Fermentation 2021, 7(4), 284; https://doi.org/10.3390/fermentation7040284 - 27 Nov 2021
Cited by 9 | Viewed by 2374
Abstract
To enhance anaerobic fermentation during food waste (FW) digestion, pretreatments can be applied or the FW can be co-digested with other waste. In this study, lipase addition (LA), hydrothermal pretreatment (HTP), and a combination of both methods (HL) were applied to hydrolyze organic [...] Read more.
To enhance anaerobic fermentation during food waste (FW) digestion, pretreatments can be applied or the FW can be co-digested with other waste. In this study, lipase addition (LA), hydrothermal pretreatment (HTP), and a combination of both methods (HL) were applied to hydrolyze organic matter in FW. Furthermore, the effects of crude glycerol (CG), which provided 5%, 10%, and 15% of the volatile solids (VS) as co-substrate (denoted as CG5, CG10, and CG15, respectively), on the anaerobic digestion of FW were assessed. With an increasing proportion of CG in the co-digestion experiment, CG10 showed higher methane production, while CG15 negatively affected the anaerobic digestion (AD) performance owing to propionic acid accumulation acidifying the reactors and inhibiting methanogen growth. As the pretreatments partially decomposed hard-to-degrade substances in advance, pretreated FW showed a stronger methane production ability compared with raw FW, especially using the HL method, which was significantly better than co-digestion. HL pretreatment was shown to be a promising option for enhancing the methane potential value (1.773 NL CH4/g VS) according to the modified Gompertz model. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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12 pages, 1127 KiB  
Article
Biomethanation of Carbon Monoxide by Hyperthermophilic Artificial Archaeal Co-Cultures
Fermentation 2021, 7(4), 276; https://doi.org/10.3390/fermentation7040276 - 25 Nov 2021
Cited by 4 | Viewed by 1999
Abstract
Climate neutral and sustainable energy sources will play a key role in future energy production. Biomethanation by gas to gas conversion of flue gases is one option with regard to renewable energy production. Here, we performed the conversion of synthetic carbon monoxide (CO)-containing [...] Read more.
Climate neutral and sustainable energy sources will play a key role in future energy production. Biomethanation by gas to gas conversion of flue gases is one option with regard to renewable energy production. Here, we performed the conversion of synthetic carbon monoxide (CO)-containing flue gases to methane (CH4) by artificial hyperthermophilic archaeal co-cultures, consisting of Thermococcus onnurineus and Methanocaldococcus jannaschii, Methanocaldococcus vulcanius, or Methanocaldococcus villosus. Experiments using both chemically defined and complex media were performed in closed batch setups. Up to 10 mol% CH4 was produced by converting pure CO or synthetic CO-containing industrial waste gases at a high rate using a co-culture of T. onnurineus and M. villosus. These findings are a proof of principle and advance the fields of Archaea Biotechnology, artificial microbial ecosystem design and engineering, industrial waste-gas recycling, and biomethanation. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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11 pages, 1404 KiB  
Article
Mathematical Analysis and Update of ADM1 Model for Biomethane Production by Anaerobic Digestion
Fermentation 2021, 7(4), 237; https://doi.org/10.3390/fermentation7040237 - 21 Oct 2021
Cited by 10 | Viewed by 2930
Abstract
Biomethane is a renewable product that can directly substitute its fossil counterpart, although its synthesis from residual biomasses has some hurdles. Because of the complex nature of both biomasses and the microbial consortia involved, innovative approaches such as mathematical modeling can be deployed [...] Read more.
Biomethane is a renewable product that can directly substitute its fossil counterpart, although its synthesis from residual biomasses has some hurdles. Because of the complex nature of both biomasses and the microbial consortia involved, innovative approaches such as mathematical modeling can be deployed to support possible improvements. The goal of this study is two-fold, as we aimed to modify a part of the Anaerobic Digestion Model No. 1 (ADM1), describing biomethane production from activated sludge, matching with its actual microbial nature, and to use the model for identifying relevant parameters to improve biomethane production. Firstly, thermodynamic analysis was performed, highlighting the direct route from glucose to biomethane as the most favorable. Then, by using MATLAB® and Simulink Toolbox, we discovered that the model fails to predict the microbiological behavior of the system. The structure of the ADM1 model was then modified by adding substrate consumption yields in equations describing microbial growth, to better reflect the consortium behavior. The updated model was tested by modifying several parameters: the coefficient of decomposition was identified to increase biomethane production. Approaching mathematical models from a microbiological point of view can lead to further improvement of the models themselves. Furthermore, this work represents additional evidence of the importance of informatics tools, such as bioprocess simulations to foster biomethane role in bioeconomy. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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14 pages, 3414 KiB  
Article
Modeling of Hydrogen Production by Applying Biomass Gasification: Artificial Neural Network Modeling Approach
Fermentation 2021, 7(2), 71; https://doi.org/10.3390/fermentation7020071 - 01 May 2021
Cited by 14 | Viewed by 3139
Abstract
In order to accurately anticipate the proficiency of downdraft biomass gasification linked with a water–gas shift unit to produce biohydrogen, a model based on an artificial neural network (ANN) approach is established to estimate the specific mass flow rate of the biohydrogen output [...] Read more.
In order to accurately anticipate the proficiency of downdraft biomass gasification linked with a water–gas shift unit to produce biohydrogen, a model based on an artificial neural network (ANN) approach is established to estimate the specific mass flow rate of the biohydrogen output of the plant based on different types of biomasses and diverse operating parameters. The factors considered as inputs to the models are elemental and proximate analysis compositions as well as the operating parameters. The model structure includes one layer for input, a hidden layer and output layer. One thousand eight hundred samples derived from the simulation of 50 various feedstocks in different operating situations were utilized to train the developed ANN model. The established ANN in the case of product biohydrogen presents satisfactory agreement with input data: absolute fraction of variance (R2) is more than 0.999 and root mean square error (RMSE) is lower than 0.25. In addition, the relative impact of biomass properties and operating parameters on output are studied. At the end, to have a comprehensive evaluation, variations of the inputs regarding hydrogen-content are compared and evaluated together. The results show that almost all of the inputs show a significant impact on the smhydrogen output. Significantly, gasifier temperature, SBR, moisture content and hydrogen have the highest impacts on the smhydrogen with contributions of 19.96, 17.18, 15.3 and 10.48%, respectively. In addition, other variables in feed properties, like C, O, S and N present a range of 1.28–8.6% and proximate components like VM, FC and A present a range of 3.14–7.67% of impact on smhydrogen. Full article
(This article belongs to the Special Issue Recent Trends in Biogenic Gas, Waste and Wastewater Fermentation)
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