EXPERIMENTS ON THE METHANE BACTERIA IN SLUDGE

1954 ◽  
Vol 1 (1) ◽  
pp. 55-64 ◽  
Author(s):  
R. L. Mylroie ◽  
R. E. Hungate

An agar culture method for determining the numbers of methanogenic bacteria in sludge was developed. Hydrogen and carbon dioxide were provided as substrate and palladium as a reduction catalyst. Sodium sulphide could also be used for reducing the medium. A methanogenic organism could be identified by correlating methane production with presence of a particular type of colony which was the most abundant. Fifteen strains which were pure cultured were all similar and were classified as Methanobacterium formicicum. The culture count for methane bacteria in sludge ranged between 105 and 108 per ml. The rate of fermentation and the efficiency of conversion of substrate into cell material were studied. Presence of an acetate-fermenting methanogenic organism was established but no pure cultures could be obtained. Methanobacterium formicicum appeared to be the only methane producer growing in the dilution series used for counts.

1921 ◽  
Vol 20 (1) ◽  
pp. 85-98 ◽  
Author(s):  
F. W. Twort ◽  
D. N. Twort

(1) Our experiments support the view that influenza is casued by B. influenzae, and that pneumococci and certain streptococci are the most important agents of secondary infections. No new type of bacterium was discovered, and no evidence was obtained of the presence of an ultra-micrascopic virus.(2) B. influenzae appears more toxic for rabbits and mice when grown on fresh liver or kidney media than when grown on blood agar or in blood broth, and this is especially so when the kidney or liver is obtained from an animal of t he same species that has previously been inoculated with a culture of the influenza bacillus.(3) Three fairly distinct special forms have been isolated from cultures of B. dysenteriae. They are probably not sexual units or stages in a true life cycle. Special large forms have also been obtained from cultures of B. influenzae, but these reverted back to the normal small type after several sub-cultures.(4) A filter-passing material has been found associated with certain micro- cocci from vaccinia and in pure cultures of members of the dysentery-typhoid- coli group of bacteria. This material breaks down and dissolves the bacteria of the cultures, and the “infection” can be carried to fresh normal cultures. The evidence is against its being a living ultra-microscopic virus infecting the bacteria, but it may have some connection with the special forms. No definite evidence of a similar dissolving material has been found associated with cultures of the influenza bacillus.(5) There is some indication that one or more of the forms isolated from pure cultures of dysentery bacilli may be special toxin-producing units, also that this function is at its maximum when the bacilli are first produced by the normal small forms or by sexual units of a normal culture. This may possibly be the case also with special forms that have been found in cultures of the influenza bacillus.(6) It is believed that non-pathogenic wild varieties of ultra-microscopic viruses must exist in nature, and that they should present less difficulty in cultivation than the pathogenic varieties. Cultivations were made from filtrates of soil, faeces and water on various special media, and the tubes incubated in various gases. The chief gases tested either alone or mixed were oxygen, nitrogen, carbon dioxide and sulphuretted hydrogen. All the results were negative, but some interesting deposit colonies were obtained on media con taining a small quantity of sodium sulphide.(7) The influenza bacillus grows in symbiosis with amoebae on blood agar, and in such cultures the bacillus lives considerably longer.(8) The influenza bacillus grows in symbiosis with a small spirillum that was isolated from a grass emulsion, and in symbiosis with an extremely minute and delicate bacterium isolated from garden soil; after passing the emulsions through a Berkefeld filter. With these delicate bacteria the influenza bacillus will grow on media containing no blood, and if an egg medium is used the mixed growth is dense, heaped up and brownish in colour. In such cultures the in fluenza bacillus may live for months.(9) The influenza and other bacilli will grow in an atmosphere of pure oxygen or pure carbon dioxide under diminished pressure.


2008 ◽  
Vol 54 (9) ◽  
pp. 742-747 ◽  
Author(s):  
Shiyong Lin ◽  
Xinying Wang ◽  
Haoxuan Zheng ◽  
Zhengguo Mao ◽  
Yong Sun ◽  
...  

Our purpose was to establish a quick and accurate real-time PCR (rtPCR) method to detect Campylobacter jejuni directly from human diarrheal stool as an alternative to traditional culture methods. To determine the consistency of rtPCR and culture method, 256 clinical diarrheal stool samples and 50 normal stool samples from healthy individuals were examined, and the whole process was double-blinded. Our data showed that the sensitivity of rtPCR in pure cultures and stool was 102CFU·mL–1and 103CFU·g–1, respectively. Of the 256 diarrheal samples, 10 specimens were successfully detected by both methods, whereas two specimens were PCR positive but culture negative. No positive results were found by these two methods in 50 normal specimens. Our data suggested that rtPCR was convenient in operation and time-saving (turnaround time 3.5–4 h), so it could be used for clinical diagnostic and epidemiological purposes.


F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 687 ◽  
Author(s):  
Tarig A. Gamar ◽  
Hassan H. Musa ◽  
Hisham N. Altayb ◽  
Mogeeb Kabbashi ◽  
Yassen Alsayed ◽  
...  

Background:  Infections by intestinal pathogens especially protozoans and helminths are considered to pose a real health problem, particularly in the tropics.  They cause considerable morbidity and mortality rates in developing countries. The high prevalence of these infections is closely correlated with poverty, poor environmental hygiene, and impoverished health services. This study aimed to detect prevalence and frequency of parasitic infections among food handlers in Khartoum Sudan.  Methods: Three hundred and fifty Food-handlers, attending public health laboratories in Khartoum, Sudan, for an annual medical check-up, were screened for intestinal parasites by four laboratory techniques viz. direct faecal examination, formal-ether concentration, Baermann technique and agar culture method. Results: The infection rate was 23.7% by Formol-Ether Concentration technique, followed by direct saline stool preparation (7.1%). Out of 83 positive samples the infection rate among different nationalities was as follows: Sudanese 68 (81.9%), Ethiopians 13 (15.7%), Syrians 2 (2.4%) and Egyptians 0 (0%). Intestinal parasites were more prevalent among males (73; 25.1%) than female food handlers (10; 16.9%). Three protozoans, nematodes, two tap worms and one trematode worm were detected among infected population: their frequency were as follows: Entamoeba histolytica (7.4%), Entamoeba coli (6.86%), Giardia lamblia (6%), Schistosoma mansoni (1.40%), Necator americanus (1.43%), Hymenolepis nana (0.68%), Strongyloides stercoralis (0.68%), Taenia saginata (0.57%), Ascaris lumbricoides (0.57%) and Trichostrongylus species (0.29%). Conclusion: The overall prevalence of protozoan infections among food handler in Khartoum state, Sudan was 20.26% while the helminthic infections was 5.97%. Formol-ether concentration technique is better for detection of intestinal parasites than the direct faecal smear technique. Likewise, Barmann’s technique confirms detection of nematodes worms especially hookworms.


Author(s):  
Iswanto Iswanto ◽  
Alfian Ma’arif ◽  
Bilah Kebenaran ◽  
Prisma Megantoro

Biogas is a gas obtained from the breakdown of organic matter (such as animal waste, human waste, and plants) by methanogenic bacteria in an oxygen-free (anaerobic) state. The biogas produced mainly consists of 50-70% methane, 30-40% carbon dioxide, and other gases in small amounts. The gas produced has a different composition depending on the type of animal that produces it. It is challenging to obtain biogas concentration data because the monitoring equipment is currently minimal. Therefore, this research discusses how to make a monitoring system for biogas reactors. Sensors are installed in the digester tank and storage tank. The installed sensors are the MQ-4 sensor to detect methane gas (CH<sub>4</sub>), MG-811 sensor to detect carbon dioxide (CO<sub>2</sub>) gas, MQ-136 sensor to detect sulfide acid gas (H<sub>2</sub>S), and Thermocouple Type-K to detect temperature. The sensor will send a signal to the control unit in Arduino Mega 2560, then processed and displayed on the liquid crystal display (LCD). The sensor calculation results' accuracy is not much different from the reference based on the sensor readings. The sensor deviation standard is below 5.0, indicating that the sensor is in precision. The sensor's linearity of MQ-4 is 0.7%, the MG-811 is 0.17%, the MQ-136 is 0.29%, and the Type-K Thermocouple is 1.19%. The installed sensor can be used to monitor gas concentration and temperature in a biogas reactor.


1996 ◽  
Vol 34 (5-6) ◽  
pp. 437-444 ◽  
Author(s):  
Sosuke Nishimura ◽  
Motoyuki Yoda

Methods for reducing the alkaline dosage in a two-phase UASB process were investigated. An alkaline simulation model was developed incorporating the recycle ratio of effluent, the mass transfer rate of carbon dioxide from the liquid to gas phase, and the dissociation of organic acids and carbonate. Model simulation showed that a considerable amount of alkaline was consumed needlessly in an attempt to neutralize bicarbonate generated in both the acidification phase and methanogenic phase. Decarbonation by bubbling air between the acidification section and UASB reactor was shown to be effective in reducing the amount of alkaline required for bicarbonate neutralization. Methanogenic bacteria in the system were not adversely affected by air bubbling during four months of continuous laboratory-scale operation.


Author(s):  
V. Kofman

В КНР ведутся активные исследования по разработке технологии ферментации избыточного активного ила с получением водорода. Процесс анаэробной ферментации состоит из трех основных стадий: гидролиз, образование водорода и кислот, образование метана. На стадии гидролиза происходит образование низкомолекулярных веществ из высокомолекулярного крахмала, волокон и белков. На стадии образования водорода и кислот гидрогеногенные и ацидогенные бактерии ферментируют низкомолекулярные вещества с образованием ряда органических кислот, водорода и диоксида углерода. На стадии образования метана метаногенные бактерии метаболизируют продукты, образовавшиеся на предыдущих стадиях с выделением метана и диоксида углерода. В результате получить водород можно только путем ингибирования активности метаногенных бактерий, не оказывая при этом воздействия на активность гидрогеногенных бактерий. С учетом этих обстоятельств разрабатывают способы интенсификации производства биоводорода. Основные усилия в данной области направлены на поиск штаммов с высокой эффективностью анаэробной ферментации. Другим направлением является выбор способа предварительной обработки активного ила из числа тепловой, кислотной, щелочной, СВЧ-обработки, стерилизации и ультразвуковой обработки. Значительные перспективы связывают с использованием консорциума микроорганизмов и смешанного субстрата, содержащего наряду с осадками сточных вод пищевые отходы, солому или навоз. В Индии получило развитие направление обработки сточных вод различных промышленных производств с получением обогащенной липидами биомассы для последующего производства биодизельного топлива. Исследования проведены с использованием бактерий Rhodococcus opacus, дрожжей Rhodosporidium kratochvilovae и микроводорослей Desmodesmus sp.In China, active research is underway for developing a technology for excess activated sludge fermentation to obtain hydrogen. The process of anaerobic fermentation includes three main stages: hydrolysis, formation of hydrogen and acids, and methane generation. At the hydrolysis stage, the formation of low-molecular substances from high-molecular starch, fibers and proteins. At the stage of the hydrogen and acids formation hydrogenogenic and acetogenic bacteria ensure the fermentation of low-molecular substances with the formation of a number of organic acids, hydrogen and carbon dioxide. At the stage of methane generation, methanogenic bacteria metabolize the products formed in the previous stages with the release of methane and carbon dioxide. As a result, hydrogen can be obtained only by inhibiting the activity of methanogenic bacteria eliminating the impact on the activity of hydrogenogenic bacteria. Considering these circumstances methods are being developed to enhance the production of biohydrogen. The main efforts in this area aim at finding strains with high efficiency of anaerobic fermentation. Another direction is choosing a method of activated sludge pre-treatment from among thermal, acid, alkaline, microwave treatment, sterilization and ultrasonic treatment. Significant prospects are associated with the use of a consortium of microorganisms and mixed substrate containing, along with wastewater sludge, food waste, straw or manure. In India, the technologies of processing various types of industrial wastewater with the production of biomass enriched with lipids for the subsequent production of biodiesel have been on the march. The studies have been performed using Rhodococcus opacus bacteria, Rhodosporidium kratochvilovae yeast and Desmodesmus sp microalgae.


2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Luxi Jiang ◽  
Rumeng Gu ◽  
Xiaomeng Li ◽  
Meijun Song ◽  
Xiaojun Huang ◽  
...  

Abstract Background Legionella pneumophila is an opportunistic waterborne pathogen of significant public health problems, which can cause serious human respiratory diseases (Legionnaires’ disease). Multiple cross displacement amplification (MCDA), a isothermal nucleic acid amplification technique, has been applied in the rapid detection of several bacterial agents. In this report, we developed a MCDA coupled with Nanoparticles-based Lateral Flow Biosensor (MCDA-LFB) for the rapid detection of L. pneumophila. Results A set of 10 primers based on the L. pneumophila specific mip gene to specifically identify 10 different target sequence regions of L. pneumophila was designed. The optimal time and temperature for amplification are 57 min and 65 °C. The limit of detection (LoD) is 10 fg in pure cultures of L. pneumophila. No cross-reaction was obtained and the specificity of MCDA-LFB assay was 100%. The whole process of the assay, including 20 min of DNA preparation, 35 min of L. pneumophila-MCDA reaction, and 2 min of sensor strip reaction, took a total of 57 min (less than 1 h). Among 88 specimens for clinical evaluation, 5 (5.68%) samples were L. pneumophila-positive by MCDA-LFB and traditional culture method, while 4(4.55%) samples were L. pneumophila-positive by PCR method targeting mip gene. Compared with culture method, the diagnostic accuracy of MCDA-LFB method was higher. Conclusions In summary, the L. pneumophila-MCDA-LFB method we successfully developed is a simple, fast, reliable and sensitive diagnostic tool, which can be widely used in basic and clinical laboratories.


2013 ◽  
Vol 76 (5) ◽  
pp. 748-754 ◽  
Author(s):  
TARO YONEKITA ◽  
TATSUYA FUJIMURA ◽  
NAOKI MORISHITA ◽  
TAKASHI MATSUMOTO ◽  
FUMIKI MORIMATSU

Shiga toxin–producing Escherichia coli (STEC) O26 has been increasingly associated with diarrheal disease all over the world. We developed an immunochromatographic (IC) strip for the rapid detection of E. coli O26 in food samples. To determine the specificity of the IC strip, pure cultures of 67 E. coli and 22 non–E. coli strains were tested with the IC strip. The IC strip could detect all (18 of 18) E. coli O26 strains tested and did not react with strains of any other E. coli serogroup or non–E. coli strains tested (0 of 71). The minimum detection limits for E. coli O26 were 2.2 ×103 to 1.0 ×105 CFU/ml. To evaluate the ability of the IC strip to detect E. coli O26 in food, 25-g food samples (ground beef, beef liver, ground chicken, alfalfa sprout, radish sprout, spinach, natural cheese, and apple juice) were spiked with E. coli O26. The IC strip was able to detect E. coli O26 at very low levels (approximately 1 CFU/25 g of food samples) after an 18-h enrichment, and the IC strip results were in 100% agreement with the results of the culture method and PCR assay. When 115 meat samples purchased from supermarkets were tested, 5 were positive for E. coli O26 with the IC strip; these results were confirmed with a PCR assay. These results suggest that the IC strip is a useful tool for detecting E. coli O26 in food samples.


2020 ◽  
Author(s):  
Aukse Sliburyte ◽  
Virgilijus Valeika

Results of the investigation of hide liming process wastewater treatment by carbon dioxide are presented in a paper. Comparison of the wastewater characteristics before and after the treatment by carbon dioxide was carried out. It was attempted to regenerate sodium sulphide using three different solutions: 10% solution of sodium carbonate and 5% or 10% solution of sodium hydroxide. The kinetic of sodium sulphide concentration, general alkalinity and pH was established. The solutions with the regenerated sodium sulphide were explored for unhairing of hide. The solution of 10% sodium hydroxide with regenerated sulphides was the mostly suitable for this aim. The properties of unhaired pelt were determined and assessed.


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