scholarly journals Colonocyte metabolism shapes the gut microbiota

Science ◽  
2018 ◽  
Vol 362 (6418) ◽  
pp. eaat9076 ◽  
Author(s):  
Yael Litvak ◽  
Mariana X. Byndloss ◽  
Andreas J. Bäumler
Keyword(s):  
Gut Microbiota ◽  
Anaerobic Bacteria ◽  
Enteric Pathogens ◽  
Metabolic Reprogramming ◽  
Human Diseases ◽  
Fermentation Products ◽  
Colonic Microbiota ◽  
Obligate Anaerobic ◽  
Control Switch ◽  
Facultative Anaerobic Bacteria

An imbalance in the colonic microbiota might underlie many human diseases, but the mechanisms that maintain homeostasis remain elusive. Recent insights suggest that colonocyte metabolism functions as a control switch, mediating a shift between homeostatic and dysbiotic communities. During homeostasis, colonocyte metabolism is directed toward oxidative phosphorylation, resulting in high epithelial oxygen consumption. The consequent epithelial hypoxia helps to maintain a microbial community dominated by obligate anaerobic bacteria, which provide benefit by converting fiber into fermentation products absorbed by the host. Conditions that alter the metabolism of the colonic epithelium increase epithelial oxygenation, thereby driving an expansion of facultative anaerobic bacteria, a hallmark of dysbiosis in the colon. Enteric pathogens subvert colonocyte metabolism to escape niche protection conferred by the gut microbiota. The reverse strategy, a metabolic reprogramming to restore colonocyte hypoxia, represents a promising new therapeutic approach for rebalancing the colonic microbiota in a broad spectrum of human diseases.

Formation and structure of granulated microbial aggregates used in aerobic wastewater treatment

2005 ◽  
Vol 52 (7) ◽  
pp. 13-19 ◽  
Author(s):  
V. Ivanov ◽  
S.T.-L. Tay ◽  
Q.-S. Liu ◽  
X.-H. Wang ◽  
Z.-W. Wang ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Anaerobic Bacteria ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Aerobic Bacteria ◽  
Structural Elements ◽  
Aerobic Wastewater Treatment ◽  
Obligate Anaerobic ◽  
Facultative Anaerobic Bacteria ◽  
Self Aggregation

Granular microbial aggregates are used in aerobic treatment of wastewater. The granules have diverse microbial community and complex spatial structure. The structural elements are radial sub-aggregates, concentric layers, channels, pores, polysaccharide plugs, and an anaerobic core of lysed cells. Aerobic bacteria, consisting of 69–84% of microbial biomass, were concentrated in a layer to the depth of 550 μm from the surface of the granule. Facultative anaerobic bacteria, consisting of 9–13% of microbial biomass, dominated in a layer at a depth from 550 μm to 850 μm from the surface of the granule. Obligate anaerobic bacteria, consisting of 2% of microbial biomass, dominated in a layer on the depth from 850 μm to 1,000 μm from the surface of the granule. A core of dead and lysed cells was at a depth greater than 1,000 μm from the surface of the granule. The depth of the anaerobic layer correlated with the appearance of polysaccharide plugs in the pores. Enrichment cultures of microorganisms with high cell surface hydrophobicity or self-aggregation ability can be used to facilitate the formation of microbial granules.

scholarly journals Діагностика та прогнозування порушень трофологічного статусу в дітей раннього віку з паралітичними синдромами, які виховуються в умовах будинку дитини

2015 ◽  
Author(s):  
Р. В Марабян ◽  
Н. І Макєєва ◽  
О. О Ріга
Keyword(s):  
Food Processing ◽  
Dietary Habits ◽  
Anaerobic Bacteria ◽  
Noninvasive Methods ◽  
Indole Butyric Acid ◽  
Diagnosis And Prognosis ◽  
Obligate Anaerobic ◽  
Colony Forming Units ◽  
Facultative Anaerobic Bacteria ◽  
Urine Levels

ДІАГНОСТИКА ТА ПРОГНОЗУВАННЯ ПОРУШЕНЬ ТРОФОЛОГІЧНОГО СТАТУСУ В ДІТЕЙ РАННЬОГО ВІКУ З ПАРАЛІТИЧНИМИ СИНДРОМАМИ, ЯКІ ВИХОВУЮТЬСЯ В УМОВАХ БУДИНКУ ДИТИНИ - У 78-ти дітей раннього віку (56 з паралітичними синдромами) проведено дослідження стосовно діагностично-прогностичних критеріїв порушення трофологічного статусу. Вивчали кількість облігатно-анаеробних бактерій, факультативно-анаеробних бактерій, умовно-патогенних мікроорганізмів, рівень метаболітів мікробіоценозу кишечника (скатол, індол, масляна кислота, молочна кислота), рівень вітамінів у сечі (В,, Вв, В12), лактату, пірувату, НАД+ та НАДФ, рівень макро-/мікроелементів волосся: магнію, цинку, кальцію, міді, калію, натрію. Неінвазивні методи дослідження визначення вмісту мікроелементів у волоссі дітей із паралітичними синдромами, рівнів кількості колонієутворювальних одиниць мікроорганізмів в 1 г фекалій та метаболітів кишечника, рівнів метаболітів сечі та вітамінів у сечі можна використовувати в якості діагностичних критеріїв порушення трофологічного статусу в дітей раннього віку з паралітичними синдромами, які перебувають в умовах будинків дитини. Автори вважають, що слід переглядати питання особливостей харчування (обробки харчових продуктів, дотація пре-/пробіотиків та ін.) дітей раннього віку з паралітичними синдромами, які виховуються в закладах закритого типу.<br />ДИАГНОСТИКА И ПРОГНОЗИРОВАНИЕ НАРУШЕНИЙ ТРОФО- ЛОГИЧНОГО СТАТУСА ДЕТЕЙ РАННЕГО ВОЗРАСТА С ПАРАЛИТИЧЕСКИМИ СИНДРОМАМИ, ВОСПИТЫВАЮЩИХСЯ В УСЛОВИЯХ ДОМА РЕБЕНКА - У 78-ти детей раннего возраста (56 из паралитическими синдромами) проведено исследование ди- агностически-прогностических критериев нарушения трофо- логического статуса. Изучались количество облигатно-анаэробных бактерий, факультативно-анаэробных бактерий, условно-патогенных микроорганизмов, уровень метаболитов микробиоценоза кишечника (скатол, индол, масляная кислота, молочная кислота), уровень витаминов в моче (В,, Вв, В12), лактата, пирувата, НАД+ и НАДФ, уровень макро-/микроэле- ментов волос: магния, цинка, кальция, меди, калия, натрия. Неинвазивные методы исследования для определения содержания микроэлементов в волосах детей с паралитическими синдромами, уровней количества колониеобразующих единиц микроорганизмов в 1 г фекалий и метаболитов кишечника, уровней метаболитов мочи и витаминов в моче можно использовать в качестве диагностических критериев нарушения трофологического статуса в детей раннего возраста с паралитическими синдромами, находящихся в условиях домов ребенка. Авторы считают, что следует пересматривать вопрос особенностей питания (обработки пищевых продуктов, дотация пре-/пробиотиков и др.) детей раннего возраста с паралитическими синдромами, воспитывающихся в учреждениях закрытого типа.<br />DIAGNOSIS AND PROGNOSIS OF VIOLATIONS TROPHOLOGICAL STATUS IN TODDLERS WITH PARALYTIC SYNDROMES BROUGHT UP IN A ORPHANAGE CONDITION - At 78 you toddlers (56 with paralytic syndromes) conducted research on diagnostic and prognostic criteria of trophological status. The number of obligate anaerobic bacteria, facultative anaerobic bacteria, pathogenic microorganisms, intestinal microbiota level of metabolites (skatole, indole, butyric acid, lactic acid) levels in urine vitamin vitamins (B1, B6, B12) and lactate, pyruvate, NAD + and NADP level macro /<br />micronutrients hair: magnesium, zinc, calcium, copper, potassium and sodium were investigated. Noninvasive methods have determined trace elements in hair of children with paralytic syndromes equal to the number of colony forming units of microorganisms in 1 g of feces and gut metabolites, urine levels of metabolites in urine and vitamins can be used as diagnostic of criteria abuse trophological status in children of early age with paralytic syndromes in orphans. The authors believe that the issue should be reviewed dietary habits (food processing, grant pre / probiotics, etc.) toddlers with paralytic syndromes who are growth in closed institutions.<br />Ключові слова: діти раннього віку, паралітичні синдроми, трофологічний статус.<br />Ключевые слова: дети раннего возраста, паралитические синдромы, трофологический статус.<br />Key words: toddlers, paralytic syndromes, trophological status.

scholarly journals Species Composition and Susceptibility to Antibiotics of Microorganisms Isolated from Tooth Sockets of Extracted Teeth in Cases of Alveolar Osteitis

2021 ◽  
Vol 83 (6) ◽  
pp. 41-48
Author(s):  
V.O. Malanchuk ◽  
◽  
A. Javadiasl ◽  
A.V. Rybachuk ◽  
M.V. Oblap ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Species Composition ◽  
Staphylococcus Epidermidis ◽  
Anaerobic Bacteria ◽  
Mixed Cultures ◽  
Anaerobic Microorganisms ◽  
Obligate Anaerobic ◽  
Alveolar Osteitis ◽  
Facultative Anaerobic Bacteria

Alveolar osteitis (AO) is one of the most common infectious complications after dental extractions. The data on the species composition of AO pathogens and their susceptibility to antimicrobial drugs can be the basis for their empirical use in case of inflammatory process aggravation. Objective. To determine the species composition and susceptibility to the antimicrobial agents of microorganisms, which were detected in patients with AO, who sought medical help in the oral surgery department of the dental medical center of Bogomolets National Medical University. Methods. Throughout 2018–2021, microbiological examination of tooth sockets from 30 patients with AO and 20 patients without AO was performed. The studied biological material was plated on appropriate nutrient media for isolation of aerobic, facultative and obligate-anaerobic microorganisms. Anaerobic conditions were achieved in GENbox 7.0 L and GENbox 2.5 L aerostats using GENbox anaerobic packages (“Biomerieux”, France). The genus and species identity of the bacteria were determined according to Bergey. Antibiotic susceptibility of the isolated strains was determined by disk diffusion method. Results. It was found that most commonly microorganisms from tooth sockets in case of AO are: Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp., Escherichia coli, Bacteroides spp., Clostridium spp., and Candida species, as well as their mixed cultures of 3–5 species of microorganisms. These aerobic and facultative anaerobic bacteria were susceptible to amoxicillin, ceftriaxone and ciprofloxacin in 92.6–100% of cases. The growth of anaerobic bacteria in 100% of cases was inhibited by colistin and meropenem. Conclusions. AO developing is caused by pathological colonization of socket of the extracted tooth by representatives of endogenous microbiota, namely Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus spp., Escherichia coli, which are present mainly in the mixed cultures with Candida albicans. For empirical antibiotic therapy of complicated forms of AO, amoxicillin or ceftriaxone or ciprofloxacin in complex with colistin or meropenem should be used, since these drugs suppress the growth of 92.6–100% of strains of aerobic, facultative and obligate anaerobic microorganisms, which are potential pathogens of the purulent forms of AO.

scholarly journals Model Selection Reveals the Butyrate-Producing Gut Bacterium Coprococcus eutactus as Predictor for Language Development in 3-Year-Old Rural Ugandan Children

2021 ◽  
Vol 12 ◽  
Author(s):  
Remco Kort ◽  
Job Schlösser ◽  
Alan R. Vazquez ◽  
Prudence Atukunda ◽  
Grace K. M. Muhoozi ◽  
...  
Keyword(s):  
Language Development ◽  
Gut Microbiota ◽  
Maternal Education ◽  
Anaerobic Bacteria ◽  
Language Ability ◽  
Campylobacter Coli ◽  
Language Impaired ◽  
Impaired Group ◽  
Facultative Anaerobic Bacteria ◽  
Impaired Children

IntroductionThe metabolic activity of the gut microbiota plays a pivotal role in the gut-brain axis through the effects of bacterial metabolites on brain function and development. In this study we investigated the association of gut microbiota composition with language development of 3-year-old rural Ugandan children.MethodsWe studied the language ability in 139 children of 36 months in our controlled maternal education intervention trial to stimulate children’s growth and development. The dataset includes 1170 potential predictors, including anthropometric and cognitive parameters at 24 months, 542 composition parameters of the children’s gut microbiota at 24 months and 621 of these parameters at 36 months. We applied a novel computationally efficient version of the all-subsets regression methodology and identified predictors of language ability of 36-months-old children scored according to the Bayley Scales of Infant and Toddler Development (BSID-III).ResultsThe best three-term model, selected from more than 266 million models, includes the predictors Coprococcus eutactus at 24 months of age, Bifidobacterium at 36 months of age, and language development at 24 months. The top 20 four-term models, selected from more than 77 billion models, consistently include C. eutactus abundance at 24 months, while 14 of these models include the other two predictors as well. Mann–Whitney U tests suggest that the abundance of gut bacteria in language non-impaired children (n = 78) differs from that in language impaired children (n = 61). While anaerobic butyrate-producers, including C. eutactus, Faecalibacterium prausnitzii, Holdemanella biformis, Roseburia hominis are less abundant, facultative anaerobic bacteria, including Granulicatella elegans, Escherichia/Shigella and Campylobacter coli, are more abundant in language impaired children. The overall predominance of oxygen tolerant species in the gut microbiota was slightly higher in the language impaired group than in the non-impaired group (P = 0.09).ConclusionApplication of the all-subsets regression methodology to microbiota data established a correlation between the relative abundance of the anaerobic butyrate-producing gut bacterium C. eutactus and language development in Ugandan children. We propose that the gut redox potential and the overall bacterial butyrate-producing capacity in the gut are important factors for language development.

scholarly journals Microbes vs. chemistry in the origin of the anaerobic gut lumen

2018 ◽  
Vol 115 (16) ◽  
pp. 4170-4175 ◽  
Author(s):  
Elliot S. Friedman ◽  
Kyle Bittinger ◽  
Tatiana V. Esipova ◽  
Likai Hou ◽  
Lillian Chau ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Anaerobic Bacteria ◽  
Taxonomic Composition ◽  
Mammalian Host ◽  
Oxidation Reactions ◽  
Germ Free ◽  
Oxygen Levels ◽  
Gut Mucosa ◽  
Facultative Anaerobic Bacteria

The succession from aerobic and facultative anaerobic bacteria to obligate anaerobes in the infant gut along with the differences between the compositions of the mucosally adherent vs. luminal microbiota suggests that the gut microbes consume oxygen, which diffuses into the lumen from the intestinal tissue, maintaining the lumen in a deeply anaerobic state. Remarkably, measurements of luminal oxygen levels show nearly identical pO2 (partial pressure of oxygen) profiles in conventional and germ-free mice, pointing to the existence of oxygen consumption mechanisms other than microbial respiration. In vitro experiments confirmed that the luminal contents of germ-free mice are able to chemically consume oxygen (e.g., via lipid oxidation reactions), although at rates significantly lower than those observed in the case of conventionally housed mice. For conventional mice, we also show that the taxonomic composition of the gut microbiota adherent to the gut mucosa and in the lumen throughout the length of the gut correlates with oxygen levels. At the same time, an increase in the biomass of the gut microbiota provides an explanation for the reduction of luminal oxygen in the distal vs. proximal gut. These results demonstrate how oxygen from the mammalian host is used by the gut microbiota, while both the microbes and the oxidative chemical reactions regulate luminal oxygen levels, shaping the composition of the microbial community throughout different regions of the gut.

Substrate use prioritization by a coculture of five species of gut bacteria fed mixtures of arabinoxylan, xyloglucan, β-glucan, and pectin

2020 ◽  
Author(s):  
Y Liu ◽  
AL Heath ◽  
B Galland ◽  
N Rehrer ◽  
L Drummond ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Dietary Fiber ◽  
Plant Cell Wall ◽  
Bacterial Species ◽  
Short Chain ◽  
Emergent Properties ◽  
Human Gut ◽  
Fermentation Products ◽  
Plant Polysaccharides ◽  
Human Gut Microbiota

© 2020 American Society for Microbiology. Dietary fiber provides growth substrates for bacterial species that belong to the colonic microbiota of humans. The microbiota degrades and ferments substrates, producing characteristic short-chain fatty acid profiles. Dietary fiber contains plant cell wall-associated polysaccharides (hemicelluloses and pectins) that are chemically diverse in composition and structure. Thus, depending on plant sources, dietary fiber daily presents the microbiota with mixtures of plant polysaccharides of various types and complexity. We studied the extent and preferential order in which mixtures of plant polysaccharides (arabinoxylan, xyloglucan, β-glucan, and pectin) were utilized by a coculture of five bacterial species (Bacteroides ovatus, Bifidobacterium longum subspecies longum, Megasphaera elsdenii, Ruminococcus gnavus, and Veillonella parvula). These species are members of the human gut microbiota and have the biochemical capacity, collectively, to degrade and ferment the polysaccharides and produce short-chain fatty acids (SCFAs). B. ovatus utilized glycans in the order β-glucan, pectin, xyloglucan, and arabinoxylan, whereas B. longum subsp. longum utilization was in the order arabinoxylan, arabinan, pectin, and β-glucan. Propionate, as a proportion of total SCFAs, was augmented when polysaccharide mixtures contained galactan, resulting in greater succinate production by B. ovatus and conversion of succinate to propionate by V. parvula. Overall, we derived a synthetic ecological community that carries out SCFA production by the common pathways used by bacterial species for this purpose. Systems like this might be used to predict changes to the emergent properties of the gut ecosystem when diet is altered, with the aim of beneficially affecting human physiology. This study addresses the question as to how bacterial species, characteristic of the human gut microbiota, collectively utilize mixtures of plant polysaccharides such as are found in dietary fiber. Five bacterial species with the capacity to degrade polymers and/or produce acidic fermentation products detectable in human feces were used in the experiments. The bacteria showed preferential use of certain polysaccharides over others for growth, and this influenced their fermentation output qualitatively. These kinds of studies are essential in developing concepts of how the gut microbial community shares habitat resources, directly and indirectly, when presented with mixtures of polysaccharides that are found in human diets. The concepts are required in planning dietary interventions that might correct imbalances in the functioning of the human microbiota so as to support measures to reduce metabolic conditions such as obesity.

The Consumption of Galactomannan Effervescent Drinks made from Coconut Pulp Waste and Colonic Microbiota in Wistar Rats

2020 ◽  
Vol 15 (1) ◽  
pp. 52-56
Author(s):  
Sri Winarti ◽  
Agung Pasetyo
Keyword(s):  
Fatty Acids ◽  
Gut Microbiota ◽  
Wistar Rats ◽  
Short Chain Fatty Acids ◽  
Short Chain ◽  
E Coli ◽  
Colonic Microbiota ◽  
Male Wistar Rats ◽  
Lactobacillus Spp ◽  
Chain Fatty Acids

The consumption of prebiotics is known to affect the balance of gut microbiota. The purpose of this study was to explore how a galactomannan-rich effervescent drink can affect the population of Lactobacillus, Bifidobacterium, E. coli, and the concentration of short-chain fatty acids in the cecum of rats. Twenty-eight male Wistar rats (aged 2 months) were divided equally into 7 groups and treated orally each day for 15 days with 2 mL effervescent drinks with increasing levels of prebiotic galactomannan. The dosage of 500 mg galactomannan increased the growth of Lactobacillus spp. and Bifidobacterium spp. with inhibition of the growth of E.coli with increased formation of short-chain fatty acids such as acetate, propionate, and butyrate in the cecum of rats.

CHANGES IN SMALL INTESTINE MICROFLORA IN PATIENTS WITH ACUTE INTESTINAL OBSTRUCTION

2020 ◽  
pp. 16-18
Author(s):  
V. M. Lykhman ◽  
O. M. Shevchenko ◽  
Ye. O. Bilodid ◽  
Igor Vladimirovich Volchenko ◽  
I. A. Kulyk ◽  
...  
Keyword(s):  
Small Intestine ◽  
Gastrointestinal Tract ◽  
Species Composition ◽  
Intestinal Obstruction ◽  
Bacterial Flora ◽  
Anaerobic Bacteria ◽  
Acute Intestinal Obstruction ◽  
Gram Positive ◽  
Mechanical Intestinal Obstruction ◽  
Facultative Anaerobic Bacteria

Among urgent surgical diseases of abdominal cavity, an acute intestinal obstruction is the most difficult to be diagnosed and treated. Leading factor, determining the development of pathophysiological processes is considered to be the progressive manifestations of enteric insufficiency syndrome, resulting in intestinal barrier impairment, negative changes in ecology of intestinal flora, increased endotoxins. To identify the small intestine microflora in acute intestinal obstruction and determine the role of dysbiotic disorders in clinical manifestations of main pathological process, a study was conducted in 60 patients with mechanical intestinal obstruction. The small intestine has a relatively rare microflora, consisting mainly of gram−positive facultative aerobic microorganisms, streptococci, lactobacilli. The distal ileum in nearly 30−55 % of healthy people contains scanty microflora, and yet the flora of this area differs from the microbial population of the higher gastrointestinal tract due to higher concentration of gram−negative bacteria. Optional−anaerobic coliform bacilli, anaerobic bifidobacteria and fusobacteria, bacteroids, the number of which starts exceeding the one of gram−positive species, are presented in significant quantities. Distal to the ileocecal valve there are significant changes in the microflora quantitative and species composition. Obligatory anaerobic bacteria become the predominant part of microflora, exceeding the number of aerobic and facultative anaerobic bacteria. The bacterial flora in different parts of gastrointestinal tract has its own specifics and is quite constant, as a result of the interaction of many factors, regulating the bacterial population in small intestine. The most important among them are: acidity of gastric juice, normal peristaltic activity of the intestine, bacterial interactions and immune mechanisms. Disorders of the intestine motor and evacuation function with its obstruction lead to slow passage of the chyme and contamination of the upper gastrointestinal tract with new types of microbes. There is a syndrome of small intestine excessive colonization, which means an increased concentration of bacterial populations in it, similar in species composition to the colon microflora. Pathological intra−intestinal contents become a source of endogenous infection and re−infection of the patient, leads to internal digestive disorders, which is manifested by syndrome of malabsorption of proteins, carbohydrates and vitamins. Key words: acute intestinal obstruction, small intestinal microflora, conditionally pathogenic microorganisms, intestinal biocenosis.

scholarly journals Zeolite addition to improve biohydrogen production from dark fermentation of C5/C6-sugars and Sargassum sp. biomass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. M. Silva ◽  
A. A. Abreu ◽  
A. F. Salvador ◽  
M. M. Alves ◽  
I. C. Neves ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Anaerobic Bacteria ◽  
Dark Fermentation ◽  
Inorganic Materials ◽  
Biohydrogen Production ◽  
High Rate ◽  
Continuous Reactor ◽  
Organic Loading Rate ◽  
Fermentation Products ◽  
Zeolite Type

AbstractThermophilic biohydrogen production by dark fermentation from a mixture (1:1) of C5 (arabinose) and C6 (glucose) sugars, present in lignocellulosic hydrolysates, and from Sargassum sp. biomass, is studied in this work in batch assays and also in a continuous reactor experiment. Pursuing the interest of studying interactions between inorganic materials (adsorbents, conductive and others) and anaerobic bacteria, the biological processes were amended with variable amounts of a zeolite type-13X in the range of zeolite/inoculum (in VS) ratios (Z/I) of 0.065–0.26 g g−1. In the batch assays, the presence of the zeolite was beneficial to increase the hydrogen titer by 15–21% with C5 and C6-sugars as compared to the control, and an increase of 27% was observed in the batch fermentation of Sargassum sp. Hydrogen yields also increased by 10–26% with sugars in the presence of the zeolite. The rate of hydrogen production increased linearly with the Z/I ratios in the experiments with C5 and C6-sugars. In the batch assay with Sargassum sp., there was an optimum value of Z/I of 0.13 g g−1 where the H2 production rate observed was the highest, although all values were in a narrow range between 3.21 and 4.19 mmol L−1 day−1. The positive effect of the zeolite was also observed in a continuous high-rate reactor fed with C5 and C6-sugars. The increase of the organic loading rate (OLR) from 8.8 to 17.6 kg m−3 day−1 of COD led to lower hydrogen production rates but, upon zeolite addition (0.26 g g−1 VS inoculum), the hydrogen production increased significantly from 143 to 413 mL L−1 day−1. Interestingly, the presence of zeolite in the continuous operation had a remarkable impact in the microbial community and in the profile of fermentation products. The effect of zeolite could be related to several properties, including the porous structure and the associated surface area available for bacterial adhesion, potential release of trace elements, ion-exchanger capacity or ability to adsorb different compounds (i.e. protons). The observations opens novel perspectives and will stimulate further research not only in biohydrogen production, but broadly in the field of interactions between bacteria and inorganic materials.

Sign in / Sign up

Export Citation Format

Share Document