Study of methanogenesis during bioutilization of plant residuals

Mahmood

The Scientific World Journal

et al. 2014

199

Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB) and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis) utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization) that deal with taxonomy and interaction and distribution of tropic groups used are also discussed.

Section: Methanogens—key Microorganisms Of the Methane Fermentatiomentioning

confidence: 99%

Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis

Mahmood

The Scientific World Journal

et al. 2014

199

“…Anaerobic processes are effective tools to reduce pollution and they fully meet cleaner energy production objectives. It has been used for wastewater treatment and more recently, for processing biodegradable industrial and agricultural wastes [1][2][3][4][5]. Anaerobic processes occur naturally in wetlands, swamps, and in the digestive tracts of ruminants [6].…”

Section: Introductionmentioning

confidence: 99%

Occurrence of Thermophilic Microorganisms in Different Full Scale Biogas Plants

Kushkevych

Cejnar

Vítězová

et al. 2019

IJMS

Background: In recent years, various substrates have been tested to increase the sustainable production of biomethane. The effect of these substrates on methanogenesis has been investigated mainly in small volume fermenters and were, for the most part, focused on studying the diversity of mesophilic microorganisms. However, studies of thermophilic communities in large scale operating mesophilic biogas plants do not yet exist. Methods: Microbiological, biochemical, biophysical methods, and statistical analysis were used to track thermophilic communities in mesophilic anaerobic digesters. Results: The diversity of the main thermophile genera in eight biogas plants located in the Czech Republic using different input substrates was investigated. In total, 19 thermophilic genera were detected after 16S rRNA gene sequencing. The highest percentage (40.8%) of thermophiles was found in the Modřice biogas plant where the input substrate was primary sludge and biological sludge (50/50, w/w %). The smallest percentage (1.87%) of thermophiles was found in the Čejč biogas plant with the input substrate being maize silage and liquid pig manure (80/20, w/w %). Conclusions: The composition of the anaerobic consortia in anaerobic digesters is an important factor for the biogas plant operator. The present study can help characterizing the impact of input feeds on the composition of microbial communities in these plants.

“…The rate of the development of digestive bacteria depends on the type of applied substrate. If the substrates are carbohydrates, the rate of bacteria generation in acid phase amounts to 5 h, whereas in the case when fats are the substrate, the time is prolonged to approximately 72 h. The generation time, in acetogenesis phase, for bacteria using propionic and fatty acidsreaches respectively 84 and 131 h. In the methanogenesis phase, the generation time ranges between 15 and 85 h (Ilyin et al, 2005;Santosh et al, 2004).…”

Section: Methanosaetaceaementioning

confidence: 99%

Methane fermentation process as anaerobic digestion of biomass: Transformations, stages and microorganisms

Ziemiński¹

2012

Afr. J. Biotechnol.

Anaerobic decomposition of organic compounds is conducted in close cooperation of specialized bacteria of different types, including mostly hydrolyzing, digestive, acetogenic, homoacetogenic, sulfate-reducing (VI) and methanogenic bacteria. A great interest in the anaerobic digestion process results mainly from its advantages, as compared to aerobic methods. The main advantages of the methane digestion process are: Production of an insignificant amount of biomass and lower energy input, as compared to degradation conducted under aerobic conditions. This paper reviews the transformations, stages and microorganisms that participate in methane fermentation process.