scholarly journals Changes in the Substrate Source Reveal Novel Interactions in the Sediment-Derived Methanogenic Microbial Community

2019 ◽  
Vol 20 (18) ◽  
pp. 4415 ◽  
Author(s):  
Anna Szafranek-Nakonieczna ◽  
Anna Pytlak ◽  
Jarosław Grządziel ◽  
Adam Kubaczyński ◽  
Artur Banach ◽  
...  

Methanogenesis occurs in many natural environments and is used in biotechnology for biogas production. The efficiency of methane production depends on the microbiome structure that determines interspecies electron transfer. In this research, the microbial community retrieved from mining subsidence reservoir sediment was used to establish enrichment cultures on media containing different carbon sources (tryptone, yeast extract, acetate, CO2/H2). The microbiome composition and methane production rate of the cultures were screened as a function of the substrate and transition stage. The relationships between the microorganisms involved in methane formation were the major focus of this study. Methanogenic consortia were identified by next generation sequencing (NGS) and functional genes connected with organic matter transformation were predicted using the PICRUSt approach and annotated in the KEGG. The methane production rate (exceeding 12.8 mg CH4 L−1 d−1) was highest in the culture grown with tryptone, yeast extract, and CO2/H2. The analysis of communities that developed on various carbon sources casts new light on the ecophysiology of the recently described bacterial phylum Caldiserica and methanogenic Archaea representing the genera Methanomassiliicoccus and Methanothrix. Furthermore, it is hypothesized that representatives of Caldiserica may support hydrogenotrophic methanogenesis.

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5423
Author(s):  
Margarita Andreas Dareioti ◽  
Aikaterini Ioannis Vavouraki ◽  
Konstantina Tsigkou ◽  
Michael Kornaros

The growing interest in processes that involve biomass conversion to renewable energy, such as anaerobic digestion, has stimulated research in this field in order to assess the optimum conditions for biogas production from abundant feedstocks, like agro-industrial wastes. Anaerobic digestion is an attractive process for the decomposition of organic wastes via a complex microbial consortium and subsequent conversion of metabolic intermediates to hydrogen and methane. The present study focused on the exploitation of liquid cow manure (LCM) and cheese whey (CW) as noneasily and easily biodegradable sources, respectively, using continuous stirred-tank reactors for biogas production, and a comparison was presented between single- and two-stage anaerobic digestion systems. No significant differences were found concerning LCM treatment, in a two-stage system compared to a single one, concluding that LCM can be treated by implementing a single-stage process, as a recalcitrant substrate, with the greatest methane production rate of 0.67 L CH4/(LR·d) at an HRT of 16 d. On the other hand, using the easily biodegradable CW as a monosubstrate, the two-stage process was considered a better treatment system compared to a single one. During the single-stage process, operational problems were observed due to the limited buffering capacity of CW. However, the two-stage anaerobic digestion of CW produced a stable methane production rate of 0.68 L CH4/(LR·d) or 13.7 L CH4/Lfeed, while the total COD was removed by 76%.


1997 ◽  
Vol 35 (8) ◽  
pp. 209-215 ◽  
Author(s):  
Shuzo Tanaka ◽  
Toshio Kobayashi ◽  
Ken-ichi Kamiyama ◽  
Ma. Lolita N. Signey Bildan

Effects of pretreatment on the anaerobic digestion of waste activated sludge (WAS) were investigated in terms of VSS solubilization and methane production by batch experiments. The methods of pretreatment studied are NaOH addition (chemical), heating (thermal) and heating with NaOH addition (thermochemical) to the domestic WAS and to the combined WAS from domestic, commercial and industrial wastewaters. The thermochemical pretreatment gave the best result among three methods in the combined WAS, i.e., the VSS was solubilized by 40-50% and the methane production increased by more than 200% over the control when the WAS was heated at 130°C for 5 minutes with the dose 0.3 g NaOH/g VSS. In the domestic WAS, the VSS solubilization rate was 70-80% but the increase of the methane production was about 30% after thermochemically pretreated. The domestic WAS consists of 41% protein, 25% lipid and 14% carbohydrate on COD basis, and the solubilization rate of protein, which is the largest constituent of the WAS, was 63% in the thermochemical pretreatment. Although the effect of the thermochemical pretreatment on the methane production was higher to the combined WAS than to the domestic WAS, the methane production rate was 21.9 ml CH4/g VSSWAS·day in the domestic WAS and 12.8 ml CH4/g VSSWAS·day in the combined WAS.


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Gemma Henderson ◽  
◽  
Faith Cox ◽  
Siva Ganesh ◽  
Arjan Jonker ◽  
...  

Abstract Ruminant livestock are important sources of human food and global greenhouse gas emissions. Feed degradation and methane formation by ruminants rely on metabolic interactions between rumen microbes and affect ruminant productivity. Rumen and camelid foregut microbial community composition was determined in 742 samples from 32 animal species and 35 countries, to estimate if this was influenced by diet, host species, or geography. Similar bacteria and archaea dominated in nearly all samples, while protozoal communities were more variable. The dominant bacteria are poorly characterised, but the methanogenic archaea are better known and highly conserved across the world. This universality and limited diversity could make it possible to mitigate methane emissions by developing strategies that target the few dominant methanogens. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. There were few strong co-occurrence patterns between microbes, suggesting that major metabolic interactions are non-selective rather than specific.


Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 860 ◽  
Author(s):  
Helen Coarita Fernandez ◽  
Diana Amaya Ramirez ◽  
Ruben Teixeira Franco ◽  
Pierre Buffière ◽  
Rémy Bayard

Different methods were tested to evaluate the performance of a pretreatment before anaerobic digestion. Besides conventional biochemical parameters, such as the biochemical methane potential (BMP), the methane production rate, or the extent of solubilization of organic compounds, methods for physical characterization were also developed in the present work. Criteria, such as the particle size distribution, the water retention capacity, and the rheological properties, were thus measured. These methods were tested on samples taken in two full-scale digesters operating with cattle manure as a substrate and using hammer mills. The comparison of samples taken before and after the pretreatment unit showed no significant improvement in the methane potential. However, the methane production rate increased by 15% and 26% for the two hammer mills, respectively. A relevant improvement of the rheological properties was also observed. This feature is likely correlated with the average reduction in particle size during the pretreatment operation, but these results needs confirmation in a wider range of systems.


2020 ◽  
Vol 14 (4) ◽  
pp. 551-557
Author(s):  
Yongku Li ◽  
Xiaomin Hu ◽  
Lei Feng

The changing parameters, as the biogas production rate, the methane production rate, the cumulative biogas amount, the cumulative methane amount, the biogas composition, pH etc. in high temperature anaerobic fermentation of chicken manure and stalks were analyzed by experiments with different mass ratios of chicken manure or livestock manure and stalks with a high C/N ratio. The methane production mechanism of high temperature anaerobic digestion of chicken manure and stalks was discussed in detail. It showed that not only the biogas production rates but also the methane production rates of R1–R7 demonstrated the trend of initial increase and then decrease after 50 d of high temperature anaerobic digestion. Besides, the gas production of R1 with pure chicken manure stopped on the 30th d of the reaction. The gas production of other groups R2–R7 also stopped on the corresponding 34th, 36th, 36th, 37th, 37th, and 37th day, respectively. At the end of the reaction, the cumulative biogas amounts and the cumulative methane amounts of R1–R7 were 411.58 and 269.54, 459.91 and 314.41, 425.32 and 294.11, 401.85 and 272.54, 382.63 and 257.07, 363.04 and 218.16, and 257.15 and 160.10 N ml/(g VS). The biogas slurry pH of R1–R7 all demonstrated a trend of initial decrease and then increase, e. g., pH of R2 reached the minimum of 5.94 on the 5th day. pH values of other groups were between 6.01 and 6.39. After the addition of 4 g of sodium bicarbonate on the 7th day, biogas slurry pH of R1–R7 all increased. pH was maintained between 7.16 and 7.44 until the end of the reaction.


2006 ◽  
Vol 54 (9) ◽  
pp. 221-227 ◽  
Author(s):  
Y. Yoneyama ◽  
A. Nishii ◽  
M. Nishimoto ◽  
N. Yamada ◽  
T. Suzuki

Upflow anaerobic sludge blanket (UASB) methane fermentation treatment of cow manure that was subjected to screw pressing, thermal treatment and subsequent solid–liquid separation was studied. Conducting batch scale tests at temperatures between 140 and 180 °C, the optimal temperature for sludge settling and the color suppression was found to be between160–170 °C. UASB treatment was carried out with a supernatant obtained from the thermal treatment at the optimal conditions (170 °C for 30 minutes) and polymer-dosed solid–liquid separation. In the UASB treatment with a CODCr loading of 11.7 kg/m3/d and water temperature of 32.2 °C, the CODCr level dropped from 16,360 mg/L in raw water to 3,940 mg/L in treated water (CODCr removal rate of 75.9%), and the methane production rate per CODCr was 0.187 Nm3/kg. Using wastewater thermal-treated at the optimal conditions, also a methane fermentation treatment with a continuously stirred tank reactor (CSTR) was conducted (CODCr in raw water: 38,000 mg/L, hydraulic retention time (HRT): 20 days, 35 °C). At the CODCr loading of 1.9 kg/m3/d, the methane production rate per CODCr was 0.153 Nm3/kg. This result shows that UASB treatment using thermal pre-treatment provides a CODCr loading of four times or more and a methane production rate of 1.3 times higher than the CSTR treatment.


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