1.Current susceptibility patterns of anaerobic bacteria.
Hannah M WEXLER ; Sydney M FINEGOLD
Yonsei Medical Journal 1998;39(6):495-501
While antibiotic resistance among anaerobes continues to increase, the frequency of antimicrobial susceptibility testing for anaerobes is declining. Because anaerobic infections are often mixed and detailed bacteriology of the organisms involved may take some time, physicians must institute empiric therapy before susceptibility testing results are available. Also, economic realities and prudent use of resources mandate that careful consideration be given to the necessity for routine susceptibility testing of anaerobic bacteria. Determination of appropriate therapy can be based on published antibiograms; however, since patterns may vary within geographic regions and even within hospitals, it is strongly recommended that each hospital center periodically test their isolates to determine local patterns and detect any pockets of resistance. As a general guide, antibiograms from the last several years of susceptibility testing at the Wadsworth Anaerobe Laboratory are reported.
Bacteria, Anaerobic/physiology*
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Drug Resistance, Microbial/physiology*
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Human
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Microbial Sensitivity Tests
2.Progress on biogas technology and engineering.
Xiaofeng LIU ; Yuexiang YUAN ; Zhiying YAN
Chinese Journal of Biotechnology 2010;26(7):924-930
Dwindling supplies of conventional energy sources and the demand to increase the share of renewable energy for sustainability have increased the significance of biogas, the product of synergistic fermentation of biodegrable organic wastes from municipal, agricultural and industrial activities by microbial populations under anaerobic conditions. With extensive research and engineering practice, many technologies and modes have been developed for biogas production and application. Currently, the most widely used mode is the complete-mixing mesophilic fermentation. Europe, especially Germany, is leading the world in the combined heat and power production (CHP) from biogas. In this paper, updated progress in biogas technologies is reviewed, with focuses on anaerobic microorganisms, bioreactor configurations and process development, biogas production and applications, in which perspectives of biogas as a clean and renewable energy are projected.
Bacteria, Anaerobic
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metabolism
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physiology
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Biodegradation, Environmental
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Bioelectric Energy Sources
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microbiology
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trends
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Biofuels
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microbiology
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Fermentation
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Industrial Microbiology
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trends
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Refuse Disposal
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methods
3.Influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste.
Man-chang WU ; Ke-wei SUN ; Yong ZHANG
Journal of Zhejiang University. Science. B 2006;7(3):180-185
A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55 degrees C to 20 degrees C suddenly; 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g/(L.d) and 15 d respectively for MOSW load and retention time, following results were noted: (1) biogas production almost stopped and VFA (volatile fatty acid) accumulated rapidly, accompanied by pH decrease; (2) with low temperature (20 degrees C) duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation; (3) the longer the low temperature interval lasted, the more the methanogenic bacteria would decay; hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation; (4) the thermophilic microorganisms were highly resilient to temperature fluctuation.
Archaea
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cytology
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physiology
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Bacteria, Anaerobic
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cytology
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physiology
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Biodegradation, Environmental
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Cell Survival
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Cities
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Fatty Acids, Volatile
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metabolism
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Hydrogen-Ion Concentration
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Methane
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metabolism
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Refuse Disposal
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methods
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Sewage
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microbiology
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Temperature
4.Cellulose hydrolysis and ethanol production by a facultative anaerobe bacteria consortium H and its identification.
Ran DU ; Shizhong LI ; Xiaoqing ZHANG ; Li WANG
Chinese Journal of Biotechnology 2010;26(7):960-965
The recalcitrance of lignocellulosic biomass makes its hydrolysis by cellulases less effective, and the consolidated bioprocessing (CBP) strategy that combines enzyme production, cellulose hydrolysis and fermentation, particularly the synergetic role of different microbes in attacking cellulose component could be a solution. In this article, a facultative anaerobe microbial consortium named H was isolated, which exhibited high stability even after 30 subcultures, with pH ranging from 6 to 9. Within three days, 0.5 g filter paper immerged in 100 mL PCS buffer was completely degraded, and 1.54 g/L ethanol was produced, correspondingly. Further analysis on the component of the microbe consortium was carried out though 16S rDNA and DGGE, and Clostridium thermosuccinogene, Clostridium straminisolvens and Clostridium isatidis that can directly convert cellulose to ethanol were identified, indicating that Clostridium spp. played important role in cellulose degradation through the synergistic coordination of different species, and the characterization of the consortium will benefit the analysis of the underlying mechanisms as well as the optimization of the CBP process for more efficient cellulose degradation and ethanol production.
Bacteria, Anaerobic
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metabolism
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Cellulase
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metabolism
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Cellulose
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metabolism
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Clostridium
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classification
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growth & development
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metabolism
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Clostridium thermocellum
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growth & development
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metabolism
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Culture Techniques
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methods
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Ethanol
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metabolism
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Fermentation
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Hydrolysis
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Industrial Microbiology
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methods
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Microbial Consortia
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physiology
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Microbial Interactions