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1.
Chinese Journal of Biotechnology ; (12): 816-830, 2021.
Article in Chinese | WPRIM | ID: wpr-878598

ABSTRACT

Due to abundant availability of shale gas and biogas, methane has been considered as one of the most potential carbon sources for industrial biotechnology. Methanotrophs carrying the native methane monooxygenase are capable of using methane as a sole energy and carbon source, which provides a novel strategy for reducing greenhouse gas emission and substituting edible substrates used in bioconversion processes. With the rapid development of genetic engineering tools and biosynthesis techniques, various strategies for improving the efficiency of methane bioconversion have been achieved to produce a variety of commodity bio-based products. Herein, we summarize several important aspects related with methane utilization and metabolic engineering of methanotrophs, including the modification of methane oxidation pathways, the construction of efficient cell factories, and biosynthesis of chemicals and fuels. Finally, the prospects and challenges of the future development of methane bioconversion are also discussed.


Subject(s)
Biofuels , Biotechnology , Metabolic Engineering , Methane , Oxidation-Reduction
2.
Chinese Journal of Biotechnology ; (12): 530-540, 2021.
Article in Chinese | WPRIM | ID: wpr-878580

ABSTRACT

One-carbon compounds such as methanol and methane are cheap and readily available feedstocks for biomanufacturing. Oxidation of methanol to formaldehyde catalyzed by methanol dehydrogenase (MDH) is a key step of microbial one-carbon metabolism. A variety of MDHs that depend on different co-factors and possess different enzymatic properties have been discovered from native methylotrophs. Nicotinamide adenine dinucleotide (NAD)-dependent MDHs are widely used in constructing synthetic methylotrophs, whereas this type of MDH usually suffers from low methanol oxidation activity and low affinity to methanol. Consequently, methanol oxidation is considered as a rate-limiting step of methanol metabolism in synthetic methylotrophs. To accelerate methanol oxidation, thereby improving the methanol utilization efficiency of synthetic methylotrophs, massive researches have focused on discovery and engineering of MDHs. In this review, we summarize the ongoing efforts to discover, characterize, and engineer various types of MDHs as well as the applications of MDHs in synthetic methylotrophs. Directed evolution of MDH and construction of multi-enzyme complexes are described in detail. In the future prospective part, we discuss the potential strategies of growth-coupled protein evolution and rational protein design for acquisition of superior MDHs.


Subject(s)
Alcohol Oxidoreductases/genetics , Carbon , Methane , Methanol
3.
Article in English | WPRIM | ID: wpr-787237

ABSTRACT

BACKGROUND/AIMS: This study aimed to identify the demographic and clinical factors associated with positive breath-test results and to assess the relationship between hydrogen and methane production in patients with suspected irritable bowel syndrome (IBS).METHODS: The demographic and clinical factors of 268 patients with suspected IBS, who had undergone a lactulose breath test, were analyzed.RESULTS: Of 268 patients included in this study, 143 (53.4%) were females. The median age and BMI of the patients was 58.0 years (range, 18.0–80.0 years) and 22.5 kg/m² (range, 14.4–34.3 kg/m²), respectively. A weak positive correlation was observed between the BMI and baseline hydrogen level (rho=0.134, p=0.031). Women were significantly more likely to show a ≥20 ppm increase in hydrogen within 90 min (early hydrogen increase, p=0.049), a ≥10 ppm increase in methane within 90 min (early methane increase, p=0.001), and a ≥10 ppm increase in methane between 90 min and 180 min (late methane increase, p=0.002) compared to men. The baseline hydrogen level was related to the baseline methane level (rho=0.592, p<0.001) and the maximal hydrogen level within 90 min was related to maximal methane level within 90 min (rho=0.721, p<0.001). Patients with an early hydrogen increase (43.8%) were more likely to show a positive result for an early methane increase compared to patients without an early increase in hydrogen (0%, p<0.001).CONCLUSIONS: Women were associated with high rates of positive lactulose breath-test results. In addition, methane production was correlated with hydrogen production.


Subject(s)
Breath Tests , Female , Humans , Hydrogen , Irritable Bowel Syndrome , Lactulose , Male , Methane , Sex Characteristics
4.
Rev. ANACEM (Impresa) ; 14(2): 29-42, 2020. ilus, tab, graf
Article in Spanish | LILACS | ID: biblio-1128982

ABSTRACT

En el sector de Quintero, desde los últimos 50 años han existido diversos hitos relacionados con la contaminación medioambiental. Iniciando con la instauración de la termoeléctrica "Ventanas" en 1950, Chilectra en 1958. En el año 1993 el ministerio de Agricultura de Chile declaró a Puchuncaví y Quintero como una "zona saturada de contaminación" por dióxido de azufre (SO2) y material particulado (MP10). En el año 2011, 135 trabajadores del complejo Ventana fallecieron producto del cáncer. Durante el 2014 hubo un derrame de petróleo en la Bahía de Quintero, 2015 un informe del Instituto de Fomento Pesquero (IFOP) arrojó cifras de arsénico que superan 23 veces la norma establecida por el Código Sanitario de Alimentos. Frente a dicho escenario, se hace evidente la necesidad de comprender cómo es la situación de los pobladores de dichas comunas. La presente investigación busca asociar los niveles de contaminación de las comuna de Quintero y el número de hospitalizaciones durante los años 2012 hasta el 2018.


In Quintero, since the last 50 years there have been various milestones related to environmental pollution. Starting with the installation of the "Ventanas" thermoelectric plant in 1950, Chilectra in 1958. In 1993, the Chilean Ministry of Agriculture declared Puchuncaví and Quintero as a "zone saturated with contamination" by sulfur dioxide (SO2) and particulate matter (MP10). In 2011, 135 workers at the Ventana complex died of cancer. During 2014 an oil spill emerged in Quintero Bay, 2015 a report by the Institute for Fisheries Development (IFOP) showed arsenic figures that exceed 23 times the norm established by the Sanitary Food Code. Faced with this scenario, the need to understand what the situation of the residents of said communes is like is evident. The present investigation seeks to associate the levels of contamination of the commun of Quintero and the number of hospitalizations during the years 2012 to 2018.


Subject(s)
Air Pollution , Environmental Exposure/statistics & numerical data , Environmental Pollutants/analysis , Hospitalization/statistics & numerical data , Ozone/analysis , Sulfur Dioxide/analysis , Chile , Regression Analysis , Risk Factors , Government Regulation , Methane/analysis , Nitrogen Dioxide/analysis
5.
Electron. j. biotechnol ; 37: 25-33, Jan. 2019. tab, graf, ilus
Article in English | LILACS | ID: biblio-1051225

ABSTRACT

Background: Ammonium stress is a prime limiting phenomenon that occurs during methane formation from poultry manure. It is caused by elevated ammonium nitrogen concentrations that result from substrate decomposition. The amounts of methane formed depend on the activity of methanogenic microbes. Results: During the research reported in this paper, the response of a mesophilic consortium inhabiting a biogas reactor to rising load of poultry manure was investigated. The taxonomic composition of bacterial population was mostly typical, however syntrophic bacteria were not detected. This absence resulted in limitation of succession of some methanogenic microorganisms, especially obligate hydrogenotrophs. The methanogenic activity of the consortium was totally dependent on the activity of Methanosaeta. Inhibition of methanoganesis was noticed at ammonium nitrogen concentration of 3.68 g/L, total cessation occurred at 5.45 g/L. Significant amounts of acetic acid in the fermentation pulp accompanied the inhibition. Conclusions: The effectiveness of the consortium was totally dependent on the metabolic activity of the acetoclastic Methanoseata genus and lack of SAOB did not allow hydrogenotrophic methanogens to propagate and lead to cessation of biogas production at an elevated ammonium concentration at which acetoclastic methanogens were inhibited.


Subject(s)
Methanosarcinaceae/metabolism , Biofuels , Microbiota , Anaerobiosis , Poultry , Stress, Physiological , Polymerase Chain Reaction , DNA Fingerprinting , Chromatography, High Pressure Liquid , Archaea/metabolism , Biodiversity , Fermentation , Microbial Consortia , Ammonium Compounds , Manure , Methane , Nitrogen
6.
Electron. j. biotechnol ; 39: 61-66, may. 2019. graf, tab
Article in English | LILACS | ID: biblio-1052032

ABSTRACT

BACKGROUND: Triclosan (TCS) is an antimicrobial agent widely used in health care and consumer products. This compound is present in sludge of wastewater treatment plants (WWTPs), and because of its bactericidal characteristics, it can inhibit the methanogenic activity in anaerobic digestion (AD) technology. The aim of this study was to evaluate the toxic effects of TCS on the methanogenic activity. RESULTS: Batch anaerobic reactors were used with TCS concentrations of 7.8, 15.7, 23.5, and 31.4 mg/L. These assays consisted in three successive feedings (I, II, and III), wherein the sludge was exposed to each TCS concentration and volatile fatty acid (VFA) substrate. For evaluation of the residual sludge activity during feeding III, only VFA was used. The results showed that the increase in TCS concentrations correlated with the reduction in methane (CH4) production. In this case, the minimum values were achieved for TCS concentration of 31.4 mg/L with CH4 levels between 101.9 and 245.3 during feedings I, II, and III. Regarding the effect of TCS on VFA consumption, an inhibitory effect was detected for TCS concentrations of 23.5 and 31.4 mg/L, with concentrations of acetic, butyric, and propionic acids at the end of the assay (37 d) between 153.6 and 206.8, 62.5 and 60.1, and 93.4 and 110 mg/L, respectively. Regarding the removal of TCS during AD, these values were above 47%. Conclusion: TCS is an inhibitor of methanogenic activity with a decrease between 63 and 70% during the different feedings. The CH4 production was not recovered during feeding III, with inhibition percentages of 21­72%.


Subject(s)
Triclosan/toxicity , Anaerobic Digestion , Methane/metabolism , Anti-Infective Agents/toxicity , Sewage , Wastewater Treatment Plants , Chromatography, High Pressure Liquid , Fatty Acids, Volatile , Anaerobiosis
7.
Electron. j. biotechnol ; 39: 98-106, may. 2019. tab, graf, ilus
Article in English | LILACS | ID: biblio-1052269

ABSTRACT

BACKGROUND: The amount of municipal solid waste (MSW) gradually increased along with the rapid development of modern cities. A large amount of landfill leachate are generated with excessive chemical oxygen demand (COD), which create a great deal of pressure on the environment-friendly treatment process. Anaerobic digestion is an ideal technique to solve the above problem. RESULTS: A thermophilic granular sludge was successfully adapted for anaerobic digestion of MSW leachate (from an aging large-scale landfill) for methane production. The COD degradation efficiency improved by 81.8%, while the methane production rate reached 117.3 mL CH4/(g VS d), which was 2.34-fold more than the control condition. The bacterial and archaeal communities involved in the process were revealed by 16S rRNA gene high-throughput pyrosequencing. The richness of the bacterial community decreased in the process of thermophilic granular sludge, while the archaeal community structure presented a reverse phenomenon. The bacterial genus, Methanosaeta was the most abundant during the mesophilic process, while Methanobacterium, Methanoculleus, Methanosaeta and Methanosarcina were more evenly distributed. The more balanced community distribution between hydrogenotrophic and acetotrophic methanogens implied a closer interaction between the microbes, which further contributed to higher methane productivity. The detailed relationship between the key functional communities and anaerobic digestion performances were demonstrated via the multivariate canonical correspondence analysis. Conclusions: With the assistance of adaptive thermophilic granular sludge, microbial community structure was more evenly distributed, while both of COD degradation rate and methane production was improved during anaerobic digestion of MSW landfill leachate.


Subject(s)
Bacteria, Anaerobic/metabolism , Solid Waste , Anaerobic Digestion , Sludge Treatment , Methane/metabolism , Sewage/microbiology , Bacteria, Anaerobic/isolation & purification , Water Pollutants, Chemical , Polymerase Chain Reaction , Urban Area , Biofuels , Biological Oxygen Demand Analysis , Hot Temperature , Anaerobiosis
8.
Article in English | WPRIM | ID: wpr-765935

ABSTRACT

BACKGROUND/AIMS: Recent studies suggest that air pollution may play a role in gastrointestinal disorders. However, the effect of long-term exposure to air pollution on childhood irritable bowel syndrome (IBS) is unclear. Hence, we conducted a nationwide cohort study to investigate the association between long-term air pollution exposure and the incidence and risk of IBS in Taiwanese children during 2000–2012. METHODS: We collected data from the Taiwan National Health Insurance Research Database, linked to the Taiwan Air Quality-Monitoring Database according to the insurant living area and the air quality-monitoring station locations. Children < 18 years old, identified from January 1st, 2000, were followed-up until IBS diagnosis or December 31st, 2012. The daily average air pollutant concentrations were categorized into 4 quartile-based groups (Q1–Q4). We measured the incidence rate, hazard ratios (HRs), and 95% confidence intervals for IBS stratified by the quartiles of air pollutant concentration. RESULTS: A total of 3537 children (1.39%) were diagnosed with IBS within the cohort during the follow-up period. The incidence rate for IBS increased from 0.84 to 1.76, from 0.73 to 1.68, from 0.85 to 1.98, and from 0.52 to 3.22 per 1000 person-years, with increase in the carbon monoxide, nitrogen dioxide, non-methane hydrocarbon, and methane quartile (from Q1 to Q4) exposure concentration, respectively. The adjusted HR for IBS increased with elevated carbon monoxide, nitrogen dioxide, non-methane hydrocarbon, and methane exposure in Q4 to 1.98, 2.14, 2.19, and 5.87, respectively, compared with Q1. CONCLUSION: Long-term ambient air pollutant exposure is an environmental risk factor for childhood IBS.


Subject(s)
Air Pollution , Carbon Monoxide , Child , Cohort Studies , Diagnosis , Follow-Up Studies , Humans , Incidence , Irritable Bowel Syndrome , Methane , National Health Programs , Nitrogen Dioxide , Risk Factors , Taiwan
9.
Braz. j. microbiol ; 49(4): 770-776, Oct.-Dec. 2018. tab, graf
Article in English | LILACS | ID: biblio-974307

ABSTRACT

ABSTRACT Anaerobic digestion is important for the management of livestock manure with high ammonia level. Although ammonia effects on anaerobic digestion have been comprehensively studied, the molecular mechanism underlying ammonia inhibition still remains elusive. In this study, based on metatranscriptomic analysis, the transcriptional profile of microbial community in anaerobic digestion under low (1500 mg L-1) and high NH4 + (5000 mg L-1) concentrations, respectively, were revealed. The results showed that high NH4 + concentrations significantly inhibited methane production but facilitated the accumulations of volatile fatty acids. The expression of methanogenic pathway was significantly inhibited by high NH4 + concentration but most of the other pathways were not significantly affected. Furthermore, the expressions of methanogenic genes which encode acetyl-CoA decarbonylase and methyl-coenzyme M reductase were significantly inhibited by high NH4 + concentration. The inhibition of the co-expressions of the genes which encode acetyl-CoA decarbonylase was observed. Some genes involved in the pathways of aminoacyl-tRNA biosynthesis and ribosome were highly expressed under high NH4 + concentration. Consequently, the ammonia inhibition on anaerobic digestion mainly focused on methanogenic process by suppressing the expressions of genes which encode acetyl-CoA decarbonylase and methyl-coenzyme M reductase. This study improved the accuracy and depth of understanding ammonia inhibition on anaerobic digestion.


Subject(s)
Bacteria/genetics , Bacteria/metabolism , Ammonia/metabolism , Bacteria/isolation & purification , Bacteria/classification , Transcription, Genetic , Bioreactors/microbiology , Fatty Acids, Volatile/metabolism , Microbiota , Anaerobiosis , Methane/metabolism
11.
Electron. j. biotechnol ; 33: 52-62, May. 2018. tab, ilus
Article in English | LILACS | ID: biblio-1025045

ABSTRACT

The use of nonrenewable energy sources to provide the worldwide energy needs has caused different problems such as global warming, water pollution, and smog production. In this sense, lignocellulosic biomass has been postulated as a renewable energy source able to produce energy carriers that can cover this energy demand. Biogas and syngas are two energy vectors that have been suggested to generate heat and power through their use in cogeneration systems. Therefore, the aim of this review is to develop a comparison between these energy vectors considering their main features based on literature reports. In addition, a techno-economic and energy assessment of the heat and power generation using these vectors as energy sources is performed. If lignocellulosic biomass is used as raw material, biogas is more commonly used for cogeneration purposes than syngas. However, syngas from biomass gasification has a great potential to be employed as a chemical platform in the production of value-added products. Moreover, the investment costs to generate heat and power from lignocellulosic materials using the anaerobic digestion technology are higher than those using the gasification technology. As a conclusion, it was evidenced that upgraded biogas has a higher potential to produce heat and power than syngas. Nevertheless, the implementation of both energy vectors into the energy market is important to cover the increasing worldwide energy demand.


Subject(s)
Biofuels/analysis , Lignin/metabolism , Power Plants , Anaerobic Digestion , Biomass , Renewable Energy , Hot Temperature , Lignin/chemistry , Methane
12.
Electron. j. biotechnol ; 29: 78-85, sept. 2017. tab, graf, ilus
Article in English | LILACS | ID: biblio-1017382

ABSTRACT

Background: Biohydrogen effluent contains a high concentration of volatile fatty acid (VFA) mainly as butyric, acetic, lactic and propionic acids. The presence of various VFAs (mixture VFAs) and their cooperative effects on two-stage biohythane production need to be further studied. The effect of VFA concentrations in biohydrogen effluent of palm oil mill effluent (POME) on methane yield in methane stage of biohythane production was investigated. Results: The methane yield obtained in low VFA loading (0.9 and 1.8 g/L) was 15­20% times greater than that of high VFA loading (3.6 and 4.7 g/L). Butyric acid at high concentrations (8 g/L) has the individual significantly negative effect the methane production process (P b 0.05). Lactic, acetic and butyric acid mixed with propionic acid at a concentration higher than 0.5 g/L has an interaction significantly negative effect on the methanogenesis process (P b 0.05). Inhibition condition had a negative effect on both bacteria and archaea with inhibited on Geobacillus sp., Thermoanaerobacterium thermosaccharolyticum, Methanoculleus thermophilus and Methanothermobacter delfuvii resulting in low methane yield. Conclusion: Preventing the high concentration of butyric acid, and propionic acid in the hydrogenic effluent could enhance methane production in two-stage anaerobic digestion for biohythane production.


Subject(s)
Propionates/metabolism , Butyrates/metabolism , Waste Water/microbiology , Methane/biosynthesis , Propionates/analysis , Butyrates/analysis , Palm Oil , Methanobacteriaceae , Archaea , Methanomicrobiaceae , Geobacillus , Fermentation , Waste Water/analysis , Hydrogen , Anaerobiosis
13.
Electron. j. biotechnol ; 26: 69-83, Mar. 2017. ilus, graf, tab
Article in English | LILACS | ID: biblio-1009757

ABSTRACT

Presently, the society is facing a serious challenge for the effective management of the increasing amount of produced municipal solid wastes. The accumulated waste has caused a series of environmental problems such as uncontrolled release of greenhouse gases. Moreover, the increasing amount of wastes has resulted in a shortage of areas available for waste disposal, resulting in a nonsustainable waste management. These problems led to serious public concerns, which in turn resulted in political actions aiming to reduce the amount of wastes reaching the environment. These actions aim to promote sustainable waste management solutions. The main objective of these policies is to promote the recycling of municipal solid waste and the conversion of waste to energy and valuable chemicals. These conversions can be performed using either biological (e.g., anaerobic digestion) or thermochemical processes (e.g., pyrolysis). Research efforts during the last years have been fruitful, and many publications demonstrated the effective conversation of municipal solid waste to energy and chemicals. These processes are discussed in the current review article together with the change of the waste policy that was implemented in the EU during the last years.


Subject(s)
Solid Waste , Waste Management/methods , Energy-Generating Resources , Anaerobic Digestion , Pyrolysis , Refuse Disposal , Cities , Ethanol , Environment , Biofuels , Hydrogen , Methane
14.
Braz. j. microbiol ; 47(3): 628-639, July-Sept. 2016. tab, graf
Article in English | LILACS | ID: lil-788957

ABSTRACT

ABSTRACT The main objective of this study was to evaluate the anaerobic conversion of vinasse into biomethane with gradual increase in organic loading rate (OLR) in two upflow anaerobic sludge blanket (UASB) reactors, R1 and R2, with volumes of 40.5 and 21.5 L in the mesophilic temperature range. The UASB reactors were operated for 230 days with a hydraulic detection time (HDT) of 2.8 d (R1) and 2.8-1.8 d (R2). The OLR values applied in the reactors were 0.2-7.5 g totalCOD (L d)−1 in R1 and 0.2-11.5 g totalCOD (L d)−1 in R2. The average total chemical oxygen demand (totalCOD) removal efficiencies ranged from 49% to 82% and the average conversion efficiencies of the removed totalCOD into methane were 48-58% in R1 and 39-65% in R2. The effluent recirculation was used for an OLR above 6 g totalCOD (L d)−1 in R1 and 8 gtotalCOD (L d)−1 in R2 and was able to maintain the pH of the influent in R1 and R2 in the range from 6.5 to 6.8. However, this caused a decrease for 53-39% in the conversion efficiency of the removed totalCOD into methane in R2 because of the increase in the recalcitrant COD in the influent. The largest methane yield values were 0.181 and 0.185 (L) CH4 (gtotal COD removed)−1 in R1 and R2, respectively. These values were attained after 140 days of operation with an OLR of 5.0-7.5 g totalCOD (L d)−1 and total COD removal efficiencies around 70 and 80%.


Subject(s)
Sewage/microbiology , Fermentation , Methane/biosynthesis , Phosphorus/metabolism , Bioreactors , Volatile Organic Compounds , Biological Oxygen Demand Analysis , Hydrogen-Ion Concentration , Anaerobiosis , Nitrogen/metabolism
15.
Arq. gastroenterol ; 53(3): 196-202, tab
Article in English | LILACS | ID: lil-787344

ABSTRACT

ABSTRACT Background - Adequate bowel preparation is critical for the quality of colonoscopy. Despite reported occurrence of colonic explosion due to methane and hydrogen production by bacterial fermentation during colonoscopy, gas exchange during the procedure is believed to be effective in lowering existing methane concentration, allowing for safe utilization of mannitol for bowel preparation. Thus, mannitol is widely used for bowel cleansing prior to colonoscopy, considering its low cost and effectiveness for bowel preparation. Objective - The aim of this study was to assess the safety of mannitol for bowel preparation, when compared to sodium phosphate (NaP). Methods - We conducted a prospective observational study in which 250 patients undergoing colonoscopy at Universidade Federal de São Paulo and Hospital Albert Einstein (São Paulo, Brazil) were approached for inclusion in the study. Patients received either mannitol (n=50) or NaP (n=200) for bowel preparation, based on physician indication. Study was conducted from August 2009 to December 2009. The main outcome of interest was presence of detectable levels of methane (CH4) during colonoscopy and reduction in such levels after gas exchange during the procedure. Methane concentrations were measured in three intestinal segments during scope introduction and withdrawal. Safety was assessed as the absence of high levels of methane, defined as 5%. Measurements were made using a multi-gas monitor (X-am 7000, Dräger Safety AG & Co. KGaA, Lübeck, Germany) connected to a plastic catheter introduced into the working channel of the colonoscope. Additional outcomes of interest included levels of O2. Methane and O2 levels are reported as ppm. Mean, difference and standard deviation of levels of gas measured in both moments were calculated and compared in both groups. Proportions of patients with detectable or high levels of methane in both groups were compared. Continuous variables were analyzed using t test and categorical variables using qui-square tests. The Ethics Committee in both study sites approved the study protocol. Results - Patients in both groups were similar regarding demographics, colonoscopy indication, ASA status and quality of bowel preparation. Seven (3.5%) patients in the NaP group had methane detected during introduction of the endoscope. Methane levels became undetectable during withdrawal of the scope. None of the patients in the mannitol group had detectable levels of methane. O2 levels did not differ in the groups. Conclusion - This is the largest study to assess the safety of mannitol for bowel preparation, considering methane measurements. Our results indicate that mannitol use is as safe as NaP, and gas exchange was efficient in reducing methane concentrations.


RESUMO Contexto - Preparo adequado é fundamental para garantia de boa qualidade em colonoscopia. Apesar de relatos de explosão do cólon durante colonoscopia, secundários à produção de metano e hidrogênio pela fermentação bacteriana, acredita-se que a troca gasosa durante o procedimento diminua a concentração existente de metano, permitindo a utilização com segurança, de manitol para o preparo de cólon. Assim, manitol é largamente utilizado para limpeza dos cólons antes da colonoscopia, especialmente devido ao seu baixo custo e eficácia. Objetivo - O objetivo do estudo foi avaliar a segurança do uso de manitol no preparo dos cólons, quando comparado ao uso de fosfo-soda (NaP). Métodos - Este foi um estudo observacional retrospectivo no qual foram incluídos 250 pacientes submetidos a colonoscopia na Universidade Federal de São Paulo e Hospital Albert Einstein (São Paulo - Brasil). Os pacientes receberam preparo de cólon com manitol (n=50) ou NaP (n=200), de acordo com preferências dos médicos que encaminharam os pacientes. O estudo foi realizado entre agosto e dezembro de 2009. O principal resultado pesquisado foi a presença de níveis detectáveis de metano (CH4) durante a colonoscopia, e a redução nestes níveis após troca gasosa durante o procedimento. As concentrações de metano foram dosadas com detector multi-gas (X-am 7000, Dräger Safety AG & Co., KGaA, Lübeck, Alemanha) conectado a um cateter plástico que foi introduzido no canal de instrumentação do colonoscópio. Outro achado de interesse foram níveis de O2. Níveis de metano e O2 foram relatados em ppm. Média, diferença entre as médias e desvio padrão nos níveis dos gases em ambos momentos foram comparados nos dois grupos. A proporção de pacientes com níveis detectáveis ou altos de metano em ambos os grupos foram comparados. Variáveis contínuas foram analisadas com teste t e variáveis categóricas com o teste do qui-quadrado. Os Comitês de Ética de ambas instituições aprovaram o protocolo do estudo. Resultados - Pacientes nos dois grupos foram comparáveis quanto aos dados demográficos, indicação para colonoscopia, classificação ASA e qualidade do preparo do cólon. Sete (3,5%) pacientes no grupo NaP tinham níveis detectáveis de metano durante a introdução do colonoscópio. Os níveis de metano se tornaram indetectáveis durante a retirada do aparelho. Nenhum dos pacientes no grupo manitol tinha níveis detectáveis de metano. Níveis de O2 foram semelhantes nos dois grupos. Conclusão - Este é o estudo com maior casuística que avaliou a segurança do uso de manitol para preparo de cólon, no que diz respeito a dosagem de metano. Nossos resultados indicam que o emprego do manitol é tão seguro quanto o NaP, e que a troca gasosa é eficaz na redução da concentração de metano.


Subject(s)
Humans , Male , Female , Adult , Aged , Aged, 80 and over , Young Adult , Phosphates/administration & dosage , Cathartics/administration & dosage , Colonoscopy/methods , Intestines/physiology , Mannitol/administration & dosage , Methane/analysis , Preoperative Care/methods , Prospective Studies , Gases/analysis , Middle Aged
16.
Gut and Liver ; : 932-938, 2016.
Article in English | WPRIM | ID: wpr-132230

ABSTRACT

BACKGROUND/AIMS: Because Methanobrevibacter smithii produces methane, delaying gut transit, we evaluated M. smithii loads in irritable bowel syndrome (IBS) patients and healthy controls (HC). METHODS: Quantitative real-time polymerase chain reaction for M. smithii was performed on the feces of 47 IBS patients (Rome III) and 30 HC. On the lactulose hydrogen breath test (LHBT, done for 25 IBS patients), a fasting methane result ≥10 ppm using 10 g of lactulose defined methane-producers. RESULTS: Of 47, 20 had constipation (IBS-C), 20 had diarrhea (IBS-D) and seven were not sub-typed. The M. smithii copy number was higher among IBS patients than HC (Log₁₀5.4, interquartile range [IQR; 3.2 to 6.3] vs 1.9 [0.0 to 3.4], p<0.001), particularly among IBS-C compared to IBS-D patients (Log₁₀6.1 [5.5 to 6.6] vs 3.4 [0.6 to 5.7], p=0.001); the copy number negatively correlated with the stool frequency (R=−0.420, p=0.003). The M. smithii copy number was higher among methane-producers than nonproducers (Log₁₀6.4, IQR [5.7 to 7.4] vs 4.1 [1.8 to 5.8], p=0.001). Using a receiver operating characteristic curve, the best cutoff for M. smithii among methane producers was Log₁₀6.0 (sensitivity, 64%; specificity, 86%; area under curve [AUC], 0.896). The AUC for breath methane correlated with the M. smithii copy number among methane producers (r=0.74, p=0.008). Abdominal bloating was more common among methane producers (n=9/11 [82%] vs 5/14 [36%], p=0.021). CONCLUSIONS: Patients with IBS, particularly IBS-C, had higher copy numbers of M. smithii than HC. On LHBT, breath methane levels correlated with M. smithii loads.


Subject(s)
Area Under Curve , Breath Tests , Constipation , Diarrhea , Fasting , Feces , Humans , Hydrogen , Irritable Bowel Syndrome , Lactulose , Methane , Methanobrevibacter , Real-Time Polymerase Chain Reaction , ROC Curve , Sensitivity and Specificity
17.
Gut and Liver ; : 932-938, 2016.
Article in English | WPRIM | ID: wpr-132227

ABSTRACT

BACKGROUND/AIMS: Because Methanobrevibacter smithii produces methane, delaying gut transit, we evaluated M. smithii loads in irritable bowel syndrome (IBS) patients and healthy controls (HC). METHODS: Quantitative real-time polymerase chain reaction for M. smithii was performed on the feces of 47 IBS patients (Rome III) and 30 HC. On the lactulose hydrogen breath test (LHBT, done for 25 IBS patients), a fasting methane result ≥10 ppm using 10 g of lactulose defined methane-producers. RESULTS: Of 47, 20 had constipation (IBS-C), 20 had diarrhea (IBS-D) and seven were not sub-typed. The M. smithii copy number was higher among IBS patients than HC (Log₁₀5.4, interquartile range [IQR; 3.2 to 6.3] vs 1.9 [0.0 to 3.4], p<0.001), particularly among IBS-C compared to IBS-D patients (Log₁₀6.1 [5.5 to 6.6] vs 3.4 [0.6 to 5.7], p=0.001); the copy number negatively correlated with the stool frequency (R=−0.420, p=0.003). The M. smithii copy number was higher among methane-producers than nonproducers (Log₁₀6.4, IQR [5.7 to 7.4] vs 4.1 [1.8 to 5.8], p=0.001). Using a receiver operating characteristic curve, the best cutoff for M. smithii among methane producers was Log₁₀6.0 (sensitivity, 64%; specificity, 86%; area under curve [AUC], 0.896). The AUC for breath methane correlated with the M. smithii copy number among methane producers (r=0.74, p=0.008). Abdominal bloating was more common among methane producers (n=9/11 [82%] vs 5/14 [36%], p=0.021). CONCLUSIONS: Patients with IBS, particularly IBS-C, had higher copy numbers of M. smithii than HC. On LHBT, breath methane levels correlated with M. smithii loads.


Subject(s)
Area Under Curve , Breath Tests , Constipation , Diarrhea , Fasting , Feces , Humans , Hydrogen , Irritable Bowel Syndrome , Lactulose , Methane , Methanobrevibacter , Real-Time Polymerase Chain Reaction , ROC Curve , Sensitivity and Specificity
18.
Arq. bras. med. vet. zootec ; 67(5): 1381-1389, tab, graf
Article in Portuguese | LILACS | ID: lil-764444

ABSTRACT

O presente artigo tem como objetivo analisar a produção de leite na região do Corede, com foco nas emissões de gases efeito estufa como uma externalidade negativa dessa importante atividade econômica. Para as estimativas de emissões, utilizou-se a metodologia Tier 1 proposta pelo IPCC. As emissões passaram de 1,0 gigagrama em 1974 para 8,64 gigagramas de CH4 em 2011, o que representa um acréscimo de 767% nas emissões estimadas para o início do período de análise. Em termos de taxa de crescimento geométrica, as emissões cresceram a uma taxa de 6,0% ao ano. No entanto, se for considerada a emissão média de metano por litro de leite produzido, pode-se observar que ela reduziu significativamente de valor durante o período analisado, passando de 58 gramas de CH4 por litro de leite produzido em 1974 para 24 gramas em 2011, ou seja, as emissões de metano por litro de leite se reduziram pela metade, evidenciando que o ganho de produtividade permite uma redução das emissões, desde que acompanhado por uma redução do rebanho e de estratégias de gestão que reduzam as emissões.


The article aims to analyze milk production in the region COREDE focusing on emissions of greenhouse gases as a negative externality of this important economic activity. For emission estimates we used the Tier 1 methodology proposed by the IPCC. Emissions increased from 1.0 in 1974 to 8.64 gigagrams CH4 in 2011, representing an increase of 767% on an estimate of the beginning of the analysis period emissions. In terms of the rate of geometric growth, emissions increased at a rate of 6.0% per year. However, if we consider the average methane emission per liter of milk produced, we can see that it reduced significantly in value during the analysis period, from 58 grams of CH4 per liter of milk produced in 1974 to 24 grams in 2011, meaning that methane emissions per liter of milk are reduced by half, showing that the productivity gain allows a reduction in emissions, since it is followed by a herd reduction and management strategies that reduce emissions.


Subject(s)
Animals , Cattle , Animal Husbandry/methods , Methane , Milk , Cattle , Greenhouse Effect/prevention & control , Fermentation
19.
Rev. MVZ Córdoba ; 20(3): 4726-4738, Sept.-Dec. 2015. ilus, tab
Article in English | LILACS, COLNAL | ID: lil-769236

ABSTRACT

Objective. To evaluate the effect of Kikuyu grass (Pennisetum clandestinum) harvested at two different ages and three forage: concentrate supplement ratios (F/C) on methane (CH4) production, dry matter digestibility (DMD), and fermentation profile using the in vitro gas production technique. Materials and methods. six treatments, resulting from the combination of pasture age (30 or 60 days) and F/C (100/0, 75/25, or 50/50) were evaluated using a 2x3 factorial design. The response variables were measured 6, 12, 24 and 48 hours after incubation. A repeated-measure over time design was used to analyze the data, and differences between means were determined with the LSMEANS procedure of SAS. Results. the youngest grass (30 days) was more digestible, produced less CH4 per gram of digestible dry matter (dDM) and more total volatile fatty acids (VFA) compared to the oldest grass (60 days; p <0.05). Reductions of the F/C ratio increased DMD and CH4 production per gram of dDM (p<0.05) but had no significant effect on VFA concentration (p>0.05). Conclusions. under in vitro conditions and pH close to neutrality, the older grass reduces DMD and increases CH4 production per gram of dDM, while a F/C reduction increases DMD and CH4 production per gram of dDM, which differs with reports conducted in vivo.


Objetivo. Evaluar el efecto de la edad del pasto kikuyo (Pennisetum clandestinum) y de la relación forraje/suplemento (F/S) sobre la producción de metano (CH4), la digestibilidad de la materia seca (DMS) y el perfil de fermentación mediante la técnica in vitro de producción de gas. Materiales y métodos. Seis tratamientos, resultantes de la combinación de los factores edad del pasto (30 y 60 días) y relación F/S (100/0, 75/25 y 50/50), fueron evaluados bajo un diseño factorial 2x3. Las variables respuesta se midieron a las 6, 12, 24 y 48 horas de incubación. Para el análisis de los datos se empleó un diseño de medidas repetidas en el tiempo y las diferencias entre medias se determinaron con el procedimiento LSMEANS de SAS. Resultados. El pasto de menor edad (30 días) fue más digestible, produjo menos CH4 por gramo de materia seca digestible (MSd) y más ácidos grasos volátiles totales (AGV) que el pasto de mayor edad (60 días, p<0.05). La reducción en la relación F/S aumentó la DMS y la producción de CH4 por gramo de MSd (p<0.05), pero no tuvo efecto estadístico sobre la concentración de AGV (p>0.05). Conclusiones. Bajo condiciones in vitro, con pH próximo a la neutralidad, la mayor edad del pasto reduce la DMS y aumenta la producción de CH4 por gramo de MSd, mientras que la reducción en la relación F/S aumenta la DMS y la producción de CH4 por gramo de MSd, último hallazgo que contrasta con los reportes in vivo.


Subject(s)
In Vitro Techniques , Carbohydrates , Methane
20.
Rev. argent. microbiol ; 47(3): 229-235, set. 2015. ilus, tab
Article in Spanish | LILACS | ID: biblio-843130

ABSTRACT

Las toneladas de residuos orgánicos que se generan anualmente en la agroindustria pueden aprovecharse como materia prima para la producción de metano. Para que los residuos orgánicos se puedan convertir a metano a gran escala, es importante que previamente se realicen sobre ellos pruebas de biodegradabilidad; un parámetro importante que conviene establecer es su potencial bioquímico de metano. En el presente trabajo se estudió la biodegradabilidad, la producción de metano y el comportamiento de poblaciones de eubacterias y arqueobacterias durante la digestión anaerobia de residuos de plátano, mango y papaya provenientes de la agroindustria, adicionando un inóculo microbiano. Los residuos de mango y plátano tenían mayor contenido de materia orgánica (94 y 75 %, respectivamente) que el residuo de papaya con base en su relación sólidos volátiles/sólidos totales. Después de 63 días de tratamiento, la mayor producción de metano se observó en la digestión anaerobia del residuo de plátano: 63,89 ml de metano por g de demanda química de oxígeno del residuo. Los resultados del potencial bioquímico de metano demostraron que el residuo de plátano tiene el mejor potencial para ser usado como materia prima en la producción de metano. A través de un análisis por PCR-DGGE con oligonucleótidos específicos se logró evaluar el tamaño y la composición de las poblaciones de eubacterias y arqueobacterias presentes en la digestión anaerobia de residuos agroindustriales a lo largo del proceso.


The tons of organic waste that are annually generated by agro-industry, can be used as raw material for methane production. For this reason, it is important to previously perform biodegradability tests to organic wastes for their full scale methanization. This paper addresses biodegradability, methane production and the behavior of populations of eubacteria and archaeabacteria during anaerobic digestion of banana, mango and papaya agroindustrial wastes. Mango and banana wastes had higher organic matter content than papaya in terms of their volatile solids and total solid rate (94 and 75 % respectively). After 63 days of treatment, the highest methane production was observed in banana waste anaerobic digestion: 63.89 ml CH4/per gram of chemical oxygen demand of the waste. In the PCR-DGGE molecular analysis, different genomic footprints with oligonucleotides for eubacteria and archeobacteria were found. Biochemical methane potential results proved that banana wastes have the best potential to be used as raw material for methane production. The result of a PCR- DGGE analysis using specific oligonucleotides enabled to identify the behavior of populations of eubacteria and archaeabacteria present during the anaerobic digestion of agroindustrial wastes throughout the process.


Subject(s)
Anaerobic Digestion/methods , Waste Management/methods , Methane/biosynthesis , Biodegradation, Environmental , Solid Waste Use , Agribusiness/prevention & control , Recycling/methods , Biological Oxygen Demand Analysis/methods , Garbage
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