{"type": "FeatureCollection", "features": [{"id": "10.1016/j.biortech.2018.11.040", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-09-22T16:15:35Z", "type": "Journal Article", "created": "2018-11-10", "title": "Effect of feed glucose and acetic acid on continuous biohydrogen production by Thermotoga neapolitana", "description": "This study focused on the effect of feed glucose and acetic acid on biohydrogen production by Thermotoga neapolitana under continuous-flow conditions. Increasing the feed glucose concentration from 11.1 to 41.6\u202fmM decreased the hydrogen yield from 3.6 (\u00b10.1) to 1.4 (\u00b10.1)\u202fmol\u202fH2/mol glucose. The hydrogen production rate concomitantly increased until 27.8\u202fmM of feed glucose but remained unaffected when feed glucose was further raised to 41.6\u202fmM. Increasing the acetic acid concentration from 0 to 240\u202fmM hampered dark fermentation in batch bioassays, diminishing the cumulative hydrogen production by 45% and the hydrogen production rate by 57%, but induced no negative effect during continuous operation. Indeed, throughout the continuous flow operation the process performance improved considerably, as indicated by the 47% increase of hydrogen yield up to 3.1 (\u00b10.1)\u202fmol\u202fH2/mol glucose on day 110 at 27.8\u202fmM feed glucose.", "keywords": ["Thermotoga neapolitana", "Feed concentration", "Glucose", "Fermentation", "0211 other engineering and technologies", "0202 electrical engineering", " electronic engineering", " information engineering", "Acetic acid; Continuous-flow dark fermentation; Feed concentration; Hydrogen; Inhibition; Thermotoga neapolitana", "02 engineering and technology", "Acetic acid", "Continuous-flow dark fermentation", "Inhibition", "Acetic Acid", "Hydrogen"]}, "links": [{"href": "https://www.iris.unina.it/bitstream/11588/726873/1/Resubmission%20to%20BiTe%202018_11_08.pdf"}, {"href": "https://doi.org/10.1016/j.biortech.2018.11.040"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Bioresource%20Technology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.biortech.2018.11.040", "name": "item", "description": "10.1016/j.biortech.2018.11.040", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.biortech.2018.11.040"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-02-01T00:00:00Z"}}, {"id": "10.1016/j.biortech.2019.122033", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-09-22T16:15:35Z", "type": "Journal Article", "created": "2019-08-18", "title": "High rate continuous biohydrogen production by hyperthermophilic Thermotoga neapolitana", "description": "This study focused on continuous-flow hydrogen production by Thermotoga neapolitana at a hydraulic retention time (HRT) decreasing from 24 to 5\u202fh. At each HRT reduction, the hydrogen yield (HY) immediately dropped, but recovered during prolonged cultivation at constant HRT. The final HY in each operating period decreased from 3.4 (\u00b10.1) to 2.0 (\u00b10.0) mol H2/mol glucose when reducing the HRT from 24 to 7\u202fh. Simultaneously, the hydrogen production rate (HPR) and the liquid phase hydrogen concentration (H2aq) increased from 82 (\u00b11) to 192 (\u00b14) mL/L/h and from 9.1 (\u00b10.3) to 15.6 (\u00b10.7) mL/L, respectively. Additionally, the effluent glucose concentration increased from 2.1 (\u00b10.1) to above 10\u202fmM. Recirculating H2-rich biogas prevented the supersaturation of H2aq reaching a value of 9.3 (\u00b10.7) mL/L, resulting in complete glucose consumption and the highest HPR of 277\u202fmL/L/h at an HRT of 5\u202fh.", "keywords": ["0211 other engineering and technologies", "02 engineering and technology", "Acetic acid", "Archaea", "01 natural sciences", "7. Clean energy", "Continuous-flow dark fermentation", "Thermotoga neapolitana", "Acetic acid; Continuous-flow dark fermentation; Gas recirculation; Hydraulic retention time; Hydrogen; Thermotoga neapolitana", "Bioreactors", "Glucose", "Fermentation", "Gas recirculation", "Hydraulic retention time", "Hydrogen", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://www.iris.unina.it/bitstream/11588/758593/1/Post-print%20for%20IRIS.pdf"}, {"href": "https://doi.org/10.1016/j.biortech.2019.122033"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Bioresource%20Technology", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.biortech.2019.122033", "name": "item", "description": "10.1016/j.biortech.2019.122033", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.biortech.2019.122033"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-12-01T00:00:00Z"}}, {"id": "10.1016/j.ijhydene.2019.01.256", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-22T16:16:07Z", "type": "Journal Article", "created": "2019-02-28", "title": "Impacts of short-term temperature fluctuations on\u00a0biohydrogen production and resilience of\u00a0thermophilic microbial communities", "description": "Abstract   Anaerobic microflora enriched for dark fermentative H2 production from a mixture of glucose and xylose was used in batch cultivations to determine the effects of sudden short-term temperature fluctuations on H2 yield and microbial community composition. Batch cultures initially cultivated at 55\u00a0\u00b0C (control) were subjected to downward (from 55\u00a0\u00b0C to 35\u00a0\u00b0C or 45\u00a0\u00b0C) or upward (from 55\u00a0\u00b0C to 65\u00a0\u00b0C or 75\u00a0\u00b0C) temperature shifts for 48\u00a0h after which, each culture was transferred to a fresh medium and cultivated again at 55\u00a0\u00b0C for two consecutive batch cycles. The average H2 yield obtained during the first cultivation at 55\u00a0\u00b0C was 2.1\u00a0\u00b1\u00a00.14\u00a0mol H2 mol\u22121 hexose equivalent. During the temperature shifts, the obtained H2 yields were 1.8\u00a0\u00b1\u00a00.15, 1.6\u00a0\u00b1\u00a00.27 and 1.9\u00a0\u00b1\u00a00.00\u00a0mol H2 mol\u22121 hexose equivalent at 35\u00a0\u00b0C, 45\u00a0\u00b0C and 65\u00a0\u00b0C, respectively, while no metabolic activity was observed at 75\u00a0\u00b0C. The sugars were completely utilized during the 48\u00a0h temperature shift to 35\u00a0\u00b0C but not at 65\u00a0\u00b0C and 45\u00a0\u00b0C. At the end of the second cycle after the different temperature shifts, the H2 yield obtained was 96.5, 91.6, 79.9 and 54.1% (second cycle after temperature shift to 35\u00a0\u00b0C, 45\u00a0\u00b0C, 65\u00a0\u00b0C and 75\u00a0\u00b0C, respectively) when compared to the average H2 yield produced in the control at 55\u00a0\u00b0C. Characterization of the microbial communities present in the control culture at 55\u00a0\u00b0C showed the predominance of Thermoanaerobacteriales, Clostridiales and Bacilliales. The microbial community composition differed based on the fluctuation temperature with Thermoanaerobacteriales being most dominant during the upward temperature fluctuations and Clostridiales being the most dominant during the downward temperature fluctuations.", "keywords": ["[SDE] Environmental Sciences", "2. Zero hunger", "570", "660", "218 Environmental engineering", "[SDV]Life Sciences [q-bio]", "116 Chemical sciences", "temperature fluctuation", "116", "02 engineering and technology", "15. Life on land", "biological H-2 production", "01 natural sciences", "[SDV] Life Sciences [q-bio]", "recovery", "dark fermentation", "218", "[SDE]Environmental Sciences", "0204 chemical engineering", "resilience", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://hal.inrae.fr/hal-02623475/file/Manuscript-Okonkwo_Temp_IJHE.pdf"}, {"href": "https://doi.org/10.1016/j.ijhydene.2019.01.256"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/International%20Journal%20of%20Hydrogen%20Energy", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.ijhydene.2019.01.256", "name": "item", "description": "10.1016/j.ijhydene.2019.01.256", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.ijhydene.2019.01.256"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-03-01T00:00:00Z"}}, {"id": "10.1016/j.ijhydene.2019.06.022", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-09-22T16:16:07Z", "type": "Journal Article", "created": "2019-06-26", "title": "H2-rich biogas recirculation prevents hydrogen supersaturation and enhances hydrogen production by Thermotoga neapolitana cf. capnolactica", "description": "Abstract   This study focused on the supersaturation of hydrogen in the liquid phase (H2aq) and its inhibitory effect on dark fermentation by Thermotoga neapolitana cf. capnolactica by increasing the agitation (from 100 to 500\u00a0rpm) and recirculating H2-rich biogas (GaR). At low cell concentrations, both 500\u00a0rpm and GaR reduced the H2aq from 30.1 (\u00b14.4) mL/L to the lowest values of 7.4 (\u00b10.7) mL/L and 7.2 (\u00b11.2) mL/L, respectively. However, at high cell concentrations (0.79\u00a0g CDW/L), the addition of GaR at 300\u00a0rpm was more efficient and increased the hydrogen production rate by 271%, compared to a 136% increase when raising the agitation to 500\u00a0rpm instead. While H2aq primarily affected the dark fermentation rate, GaR concomitantly increased the hydrogen yield up to 3.5\u00a0mol H2/mol glucose. Hence, H2aq supersaturation highly depends on the systems gas-liquid mass transfer and strongly inhibits dark fermentation.", "keywords": ["Thermotoga neapolitana", "End product inhibition", "Dark fermentation; End product inhibition; Gas recirculation; Hydrogen supersaturation; Sparging; Thermotoga neapolitana", "Hydrogen supersaturation", "Sparging", "7. Clean energy", "01 natural sciences", "Gas recirculation", "Dark fermentation", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://www.iris.unina.it/bitstream/11588/756486/1/Post-print%20for%20IRIS.pdf"}, {"href": "https://doi.org/10.1016/j.ijhydene.2019.06.022"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/International%20Journal%20of%20Hydrogen%20Energy", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.ijhydene.2019.06.022", "name": "item", "description": "10.1016/j.ijhydene.2019.06.022", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.ijhydene.2019.06.022"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-07-01T00:00:00Z"}}, {"id": "10.1016/j.renene.2019.02.126", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-09-22T16:16:19Z", "type": "Journal Article", "created": "2019-02-25", "title": "Influence of liquid-phase hydrogen on dark fermentation by Thermotoga neapolitana", "description": "Abstract   Hydrogen is a strong inhibitor of dark fermentation. We aimed at directly correlating the hydrogen production by Thermotoga neapolitana with the supersaturation of hydrogen in the liquid phase (H2aq), which is often disregarded. Different agitation speeds, biogas recirculation and bubble induction by AnoxK\u2122 K1 carrier were tested to prevent the supersaturation of H2aq. At 100\u202frpm agitation, the H2aq was 29.7 (\u00b11.4) mL/L, which is 3-times higher than 9.7\u202fmL/L, i.e. the equilibrium concentration given by Henry's law. Increasing the agitation speed up to 600\u202frpm reduced the H2aq until 8.5 (\u00b10.1) mL/L in 2\u202fh and increased the hydrogen production rate (HPR) from 39 (\u00b12) mL/L/h at 0\u202frpm to 198 (\u00b14) mL/L/h at 600\u202frpm. Similar to 600\u202frpm, biogas recirculation and the presence of K1 carrier at 200\u202frpm maintained the H2aq below the equilibrium concentration. This study demonstrates the reciprocal influence of HPR and H2aq and revealed an inverse nonlinear correlation between the two parameters. Therefore, we conclude that an adequate gas-liquid mass transfer, efficiently provided by biogas recirculation or the presence of solid materials (e.g. a biomass carrier), is essential to remove H2 from the liquid phase and prevent H2 supersaturation.", "keywords": ["Thermotoga neapolitana", "gas recirculation", "dark fermentation", "13. Climate action", "supersaturation", "hydrogen inhibition", "hyperthermophilic", "02 engineering and technology", "Thermotoga neapolitana", " hyperthermophilic", " dark fermentation", " gas recirculation", " hydrogen inhibition", " supersaturation", "0204 chemical engineering", "7. Clean energy", "01 natural sciences", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://www.iris.unina.it/bitstream/11588/743161/1/Resubmission%20manuscript.pdf"}, {"href": "https://doi.org/10.1016/j.renene.2019.02.126"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Renewable%20Energy", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1016/j.renene.2019.02.126", "name": "item", "description": "10.1016/j.renene.2019.02.126", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1016/j.renene.2019.02.126"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-09-01T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=dark+fermentation&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=dark+fermentation&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=dark+fermentation&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=dark+fermentation&offset=5", "hreflang": "en-US"}], "numberMatched": 5, "numberReturned": 5, "distributedFeatures": [], "timeStamp": "2026-09-22T22:51:18.371263Z"}