scholarly journals Self-Synchronized Oscillatory Metabolism of Clostridium pasteurianum in Continuous Culture

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 137 ◽  
Author(s):  
Erin E Johnson ◽  
Lars Rehmann
Keyword(s):  
Redox Potential ◽  
Continuous Culture ◽  
H2 Production ◽  
Gas Production ◽  
Glycerol Metabolism ◽  
Clostridium Pasteurianum ◽  
Continuous Stirred Tank Reactor ◽  
Industrial Fermentation ◽  
Oxidative Pathway ◽  
Product Profile

By monitoring the real-time gas production (CO2 and H2) and redox potential at high sampling frequency in continuous culture of Clostridium pasteurianum on glycerol as sole carbohydrate, the self-synchronized oscillatory metabolism was revealed and studied. The oscillations in CO2 and H2 production were in sync with each other and with both redox potential and glycerol in the continuous stirred tank reactor (CSTR). There is strong evidence that the mechanism for this is in the regulation of the oxidative pathway of glycerol metabolism, including glycolysis, and points toward complex, concerted cycles of enzyme inhibition and activation by pathway intermediates and/or redox equivalents. The importance of understanding such an “oscillatory metabolism” is for developing a stable and highly productive industrial fermentation process for butanol production, as unstable oscillations are unproductive. It is shown that the oscillatory metabolism can be eradicated and reinstated and that the period of oscillations can be altered by modification of the operating parameters. Synchronized oscillatory metabolism impacted the product profile such that it lowered the selectivity for butanol and increased the selectivity for ethanol. This elucidates a possible cause for the variability in the product profile of C. pasteurianum that has been reported in many previous studies.

The Study on Anaerobic Fermentative Biological Hydrogen Production with Organic Wastes

2010 ◽  
Vol 113-116 ◽  
pp. 1476-1480
Author(s):  
Xiao Ye Liu ◽  
Yi Sun ◽  
Jian Yu Yang ◽  
Yong Feng Li
Keyword(s):  
Ph Value ◽  
Biogas Production ◽  
Removal Rate ◽  
Maximum Yield ◽  
Liquid Product ◽  
Oxygen Demand ◽  
H2 Production ◽  
Hydrogen Yield ◽  
Continuous Stirred Tank Reactor ◽  
Brown Sugar

This papre discussed the ability of H2-production and wastewater treatment, a continuous stirred tank reactor (CSTR)using a synthesized substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. The results show that when the pH value was 4.0～4.5, OLR was 24.5kg/(m3•d), oxidation-reduction potential was -350～-450mv, temperature was 34.0°C～36.0°C, hydraulic retention time was 6h～8h, the maximum yield of biogas production reached 20L/d and the maximum content of hydrogen is 70%. Detection of the end liquid product, ethanol and acetic acid are main, they are 70% ~90% of the total liquid product, so that is called ethanol-type fermentation.

scholarly journals Effect of Structural Individual Low-FODMAP Dietary Advice vs. Brief Advice on a Commonly Recommended Diet on IBS Symptoms and Intestinal Gas Production

Nutrients ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2856 ◽  
Author(s):  
Tanisa Patcharatrakul ◽  
Akarawut Juntrapirat ◽  
Narisorn Lakananurak ◽  
Sutep Gonlachanvit
Keyword(s):  
Abdominal Pain ◽  
Gastrointestinal Symptoms ◽  
H2 Production ◽  
Gas Production ◽  
Dietary Advice ◽  
Intestinal Gas ◽  
Food Diaries ◽  
Irritable Bowel ◽  
Fodmap Diet ◽  
Brief Advice

A low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet has been recommended for irritable bowel syndrome (IBS) patients. This study compared the efficacy of two types of dietary advice: (1) brief advice on a commonly recommended diet (BRD), and (2) structural individual low-FODMAP dietary advice (SILFD). Patients with moderate-to-severe IBS were randomized to BRD or SILFD groups. Gastrointestinal symptoms, 7-day food diaries, and post-prandial breath samples were evaluated. The SILFD included (1) identifying high-FODMAP items from the diary, (2) replacing high-FODMAP items with low-FODMAP ones by choosing from the provided menu. The BRD included reducing traditionally recognized foods that cause bloating/abdominal pain and avoidance of large meals. Responders were defined as those experiencing a ≥30% decrease in the average of daily worst abdominal pain/discomfort after 4 weeks. Sixty-two patients (47 F, age 51 ± 14 years), BRD (n = 32) or SILFD (n = 30), completed the studies. Eighteen (60%) patients in SILFD vs. 9 (28%) in the BRD group fulfilled responder criteria (p = 0.001). Global IBS symptom severity significantly improved and the number of high-FODMAP items consumed was significantly decreased after SILFD compared to BRD. Post-prandial hydrogen (H2) breath production after SILFD was significantly lower than was seen after BRD (p < 0.001). SILFD was more effective than BRD. This advice method significantly reduced FODMAP intake, improved IBS symptoms, and lowered intestinal H2 production.

EFFECTS OF TEMPERATURE ON NO3− AND NO2− REDUCTION, NITROGENOUS GAS PRODUCTION, AND REDOX POTENTIAL IN A SATURATED SOIL

1973 ◽  
Vol 53 (2) ◽  
pp. 213-218 ◽  
Author(s):  
L. D. BAILEY ◽  
E. G. BEAUCHAMP
Keyword(s):  
Redox Potential ◽  
Nitrogen Source ◽  
Low Temperatures ◽  
Slow Rate ◽  
Gas Production ◽  
Saturated Soil ◽  
Anaerobic Conditions ◽  
Ap Horizon ◽  
Effects Of Temperature ◽  
No2 Reduction

Samples of the Ap horizon of a Huron soil were used to investigate the effects of temperature on NO3− and NO2− reduction, nitrogenous gas production, and redox potential under anaerobic conditions in the laboratory. NO3− and NO2− reduction occurred at redox potential (Eh) values of 200 and 180 mV, respectively. The rate of NO3− and NO2− reduction decreased with decreasing temperatures (30–5 C). At 5 C, NO3− reduction was completely inhibited but NO2− reduction continued at a slow rate. Gas chromatographic analyses showed that the denitrification gas was composed of N2, N2O, and NO. Decreasing the temperature decreased the production of N2, increased the production of NO, and did not significantly affect the production of N2O. The increased production of NO at low temperatures when NO2− was the nitrogen source is attributed to chemodenitrification processes.

scholarly journals Unravelling methanogenesis in ruminants, horses and kangaroos: the links between gut anatomy, microbial biofilms and host immunity

2018 ◽  
Vol 58 (7) ◽  
pp. 1175 ◽  
Author(s):  
R. A. Leng
Keyword(s):  
Gut Microbiota ◽  
Close Association ◽  
Methanogenic Archaea ◽  
H2 Production ◽  
Gas Production ◽  
Gas Pressure ◽  
Lymphoid Cells ◽  
Lymphoid Tissues ◽  
Microbial Biofilms ◽  
Kinetics Of

The present essay aims to resolve the question as to why macropod marsupials (e.g. kangaroos and wallabies, hereinafter termed ‘macropods) and horses produce much less methane (CH4) than do ruminants when digesting the same feed. In herbivores, gases produced during fermentation of fibrous feeds do not pose a major problem in regions of the gut that have mechanisms to eliminate them (e.g. eructation in the rumen and flatus in the lower bowel). In contrast, gas pressure build-up in the tubiform forestomach of macropods or in the enlarged tubiform caecum of equids would be potentially damaging. It is hypothesised that, to prevent this problem, evolution has favoured development of controls over gut microbiota that enable enteric gas production (H2 and CH4) to be differently regulated in the forestomach of macropods and the caecum of all three species, from the forestomach of ruminants. The hypothesised regulation depends on interactions between their gut anatomy and host-tissue immune responses that have evolved to modify the species composition of their gut microbiota which, importantly, are mainly in biofilms. Obligatory H2 production during forage fermentation is, thus, captured in CH4 in the ruminant where ruminal gases are readily released by eructation, or in acetate in the macropod forestomach and equid caecum–colon where a build-up in gas pressure could potentially damage these organs. So as to maintain appropriate gut microbiota in different species, it is hypothesised that blind sacs at the cranial end of the haustral anatomy of the macropod forestomach and the equid caecum are sites of release of protobiofilm particles that develop in close association with the mucosal lymphoid tissues. These tissues release immune secretions such as antimicrobial peptides, immunoglobulins, innate lymphoid cells and mucin that eliminate or suppress methanogenic Archaea and support the growth of acetogenic microbiota. The present review draws on microbiological studies of the mammalian gut as well as other microbial environments. Hypotheses are advanced to account for published findings relating to the gut anatomy of herbivores and humans, the kinetics of digesta in ruminants, macropods and equids, and also the composition of biofilm microbiota in the human gut as well as aquatic and other environments where the microbiota exist in biofilms.

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