Comparison of microbial communities during the anaerobic digestion of Gracilaria under mesophilic and thermophilic conditions

Azizi, Aqil; Kim, Wonduck; Lee, Jung Hyun

doi:10.1007/s11274-016-2112-6

Cited by 24 publications

(15 citation statements)

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“…In R1 and R5, the methane and biogas yield were much lower than other rectors. In addition, the accumulation of acetate in R1 and R5 might result in the acidification in these reactors, which can deteriorate the anaerobic digestion process [36,37]. These physiochemical parameters of the reactors indicated that 1% RF concentration could not start the anaerobic digestion successfully, and 5% RF concentration could not achieve high methane production.…”

Section: Discussionmentioning

confidence: 99%

Characterization of the Microbial Communities in Rumen Fluid Inoculated Reactors for the Biogas Digestion of Wheat Straw

Zhu

Zhang

et al. 2017

Sustainability

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Abstract:The present study investigated the effect of rumen fluid (RF) concentration on the methane production through anaerobic digestion of wheat straw in batch mode, and compared the microbial communities in RF and RF inoculated reactors by 16S rRNA genes sequencing. Six levels of RF concentration including 1%, 5%, 10%, 15%, 20% and 25% (v/v) were used in reactors R1, R5, R10, R15, R20 and R25 respectively. The results revealed that lower than or equal to 5% RF concentrations resulted in reactor acidification and low methane production. The highest methane yield of 106 mL·CH 4 · g·VS −1 was achieved in R10, whereas higher RF concentrations than 10% could not improve the methane production significantly. Methanosarcina barkeri was abundant in the well-working reactors, and Methanobacterium was dominant in the poor-working reactors, implying the archaeal communities in reactors had changed greatly from the Methanobrevibacter-dominated RF. Although the relative abundance of Clostridium and Ruminococcus were greatly different between RF and reactors, the Bacteroidetes and Firmicutes communities were dominant in all the tested samples. The results indicated that the in vitro anaerobic conditions had altered the rumen methanogenic communities significantly and the facultative acetoclastic Methanosarcina was important for the methane production in the RF seeded reactors.

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Section: Discussionmentioning

confidence: 99%

Characterization of the Microbial Communities in Rumen Fluid Inoculated Reactors for the Biogas Digestion of Wheat Straw

Zhu

Zhang

et al. 2017

Sustainability

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“…Purple nonsulfur bacteria are well-studied for their ability to grow under photoheterotrophic conditions using energy from light and various VFAs as carbon and electron sources. VFAs are common fermentation byproducts, and among them, acetate is usually one of the most abundant VFAs produced during the acidogenic and acetogenic phases of anaerobic digestion (3,4). Rs.…”

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confidence: 99%

Genetic Plasticity and Ethylmalonyl Coenzyme A Pathway during Acetate Assimilation in Rhodospirillum rubrum S1H under Photoheterotrophic Conditions

Meur

Deutschbauer

Koch

et al. 2018

Appl Environ Microbiol

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Purple nonsulfur bacteria represent a promising resource for biotechnology because of their great metabolic versatility. has been widely studied regarding its metabolism of volatile fatty acid, mainly acetate. As the glyoxylate shunt is unavailable in, the citramalate cycle pathway and the ethylmalonyl-coenzyme A (CoA) pathway are proposed as alternative anaplerotic pathways for acetate assimilation. However, despite years of debate, neither has been confirmed to be essential. Here, using functional genomics, we demonstrate that the ethylmalonyl-CoA pathway is required for acetate photoassimilation. Moreover, an unexpected reversible long-term adaptation is observed, leading to a drastic decrease in the lag phase characterizing the growth of in the presence of acetate. Using proteomic and genomic analyses, we present evidence that the adaptation phenomenon is associated with reversible amplification and overexpression of a 60-kb genome fragment containing key enzymes of the ethylmalonyl-CoA pathway. Our observations suggest that a genome duplication and amplification phenomenon is not only involved in adaptation to acute stress but can also be important for basic carbon metabolism and the redox balance. Purple nonsulfur bacteria represent a major group of anoxygenic photosynthetic bacteria that emerged as a promising resource for biotechnology because of their great metabolic versatility and ability to grow under various conditions. S1H has notably been selected by the European Space Agency to colonize its life support system, called MELiSSA, due to its capacity to perform photoheterotrophic assimilation of volatile fatty acids (VFAs), mainly acetate. VFAs are valuable carbon sources for many applications, combining bioremediation of contaminated environments with the generation of added-value products. Acetate is one of the major volatile fatty acids generated as a by-product of fermentation processes. In, purple nonsulfur bacteria, the assimilation of acetate is still under debate since two different pathways have been proposed. Here, we clearly demonstrate that the ethylmalonyl-CoA pathway is the major anaplerotic pathway for acetate assimilation in this strain. Interestingly, we further observed that gene duplication and amplification, which represent a well-known phenomenon in antibiotic resistance, also play a regulatory function in carbon metabolism and redox homeostasis.

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“…Initial degradation of organic matter has been recorded to involve Proteobacteria, with many of them utilizing glucose and VFAs. Synergistetes have also been recorded to be related to the utilization of acetate …”

Section: Resultsmentioning

confidence: 99%

“…Synergistetes have also been recorded to be related to the utilization of acetate. [38][39][40] On day 10, the proportion of Bacteroidetes and Firmicutes in the intermittent reflux test (upper layer: 74.18%; lower layer: 52.1%) was generally higher than in the continuous reflux test (upper layer: 57.76%; lower layer: 47.34%). This selective enrichment might correlate with the improved cellulose degradation and it may account for the greater methane production in the intermittent reflux test.…”

Section: Wileyonlinelibrarycom/jctbmentioning

confidence: 99%

Leachate recirculation effects on solid‐state anaerobic digestion of Pennisetum hybrid and microbial community analysis

Xing

Kong

Dong

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND A leach‐bed reactor (LBR) with leachate recirculation is a suitable technology for lignocellulosic biomass anaerobic digestion. In this study, the effect of percolate reflux strategies (continuous recirculation and intermittent recirculation) on methane production from Pennisetum hybrid, a type of energy crop, was investigated using a two‐layered LBR. RESULTS Compared to a solid‐state anaerobic digestion batch test, LBRs with percolate recirculation provide a stable process with a short lag phase by avoiding inhibition of volatile fatty acid accumulation and inoculation effect. The results also indicated that continuous reflux led to a lower accumulative methane yield (56.20 L kg−1 VS) compared to intermittent reflux (78.50 L kg−1 VS), resulting from washing effect and poorer distribution on the lower layer. According to microbial analysis, Bacteroidetes, Firmicutes, Proteobacteria and Synergistetes were the most predominant bacterial phyla in each LBR test sample and aceticlastic methanogen (at least >55%) plays a predominant role for methane production in all samples. CONCLUSIONS The results indicate that leachate recirculation could provide stable conditions for methane yield; however, two‐layer reactor designs which cannot guarantee the desired distribution in the lower layer result in a low methane yield. Suitable design of LBRs to maintain a well‐distributed reflux leachate should be further investigated. © 2019 Society of Chemical Industry

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Comparison of microbial communities during the anaerobic digestion of Gracilaria under mesophilic and thermophilic conditions

Cited by 24 publications

References 50 publications

Characterization of the Microbial Communities in Rumen Fluid Inoculated Reactors for the Biogas Digestion of Wheat Straw

Characterization of the Microbial Communities in Rumen Fluid Inoculated Reactors for the Biogas Digestion of Wheat Straw

Genetic Plasticity and Ethylmalonyl Coenzyme A Pathway during Acetate Assimilation in Rhodospirillum rubrum S1H under Photoheterotrophic Conditions

Leachate recirculation effects on solid‐state anaerobic digestion of Pennisetum hybrid and microbial community analysis

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