The effect of yellow affinity substance on cellulases of
            <b>
              <i>Ruminococcus flavefaciens</i>
            </b>

Kopečný, J.; Hodrová, B.

doi:10.1046/j.1472-765x.1997.00202.x

Cited by 16 publications

(9 citation statements)

References 5 publications

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“…Furthermore, isolates of subgroup B of group 2 (Fig. 1) produced a yellow affinity substance when grown on filter paper, indicating that these bacteria produce probably the carotenoid-like compound that adheres to fiber and mediates the adsorption of bacterial cellulases as was reported for ruminococci by Kopečný and Hodrová (1997).…”

Section: 2mentioning

confidence: 66%

Ecological and physiological characterization shows that Fibrobacter succinogenes is important in rumen fiber digestion — Review

2008

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Fibrobacter succinogenes is a major cellulolytic species in the rumen. On the basis of molecular data, this species can be classified into four phylogenetic groups. Recently gathered ecological and physiological data have revealed the importance of this species, particularly phylogenetic group 1, in rumen fiber digestion. These data indicate that group 1 should be the focus of future efforts to maximize the fibrolytic function of the rumen.

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Section: 2mentioning

confidence: 66%

Ecological and physiological characterization shows that Fibrobacter succinogenes is important in rumen fiber digestion — Review

2008

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“…An alternative possibility is related to the discoloration of the filter paper. Such discoloration has been previously reported and attributed to a poorly defined "yellow affinity substance" produced by certain anaerobic bacteria that reportedly serves as an affinity agent for endo-and exo-glucanases (Kopečný and Hodrová 1997;Ljungdahl et al 1983). Thus, processes apparently occurred during the lag phase that did not release fermentable sugars and were not detectable by the cellulose activity assay, but were important for increasing the susceptibility of cellulose to hydrolysis to six-carbon sugars following expression of critical enzyme(s), at some time between days 4 and 6 (Fig.…”

Section: Dashed Lines Indicate Fitted Datamentioning

confidence: 74%

Applying theories of microbial metabolism for induction of targeted enzyme activity in a methanogenic microbial community at a metabolic steady state

Speda

Johansson

Jonsson

et al. 2016

Appl Microbiol Biotechnol

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Novel enzymes that are stable in diverse conditions are intensively sought because they offer major potential advantages in industrial biotechnology, and microorganisms in extreme environments are key sources of such enzymes. However, most potentially valuable enzymes are currently inaccessible due to the pure culturing problem of microorganisms. Novel metagenomic and metaproteomic techniques that circumvent the need for pure cultures have theoretically provided possibilities to identify all genes and all proteins in microbial communities, but these techniques have not been widely used to directly identify specific enzymes because they generate vast amounts of extraneous data.In a first step towards developing a metaproteomic approach to pinpoint targeted extracellular hydrolytic enzymes of choice in microbial communities, we have generated and analyzed the necessary conditions for such an approach by the use of a methanogenic microbial community maintained on a chemically defined medium. The results show that a metabolic steady state of the microbial community could be reached, at which the expression of the targeted hydrolytic enzymes were suppressed, and that upon enzyme induction a distinct increase in the targeted enzyme expression was obtained. Furthermore, no cross talk in expression was detected between the two focal types of enzyme activities under their respective inductive conditions. Thus, the described approach should be useful to generate ideal samples, collected before and after selective induction, in controlled microbial communities to clearly discriminate between constituently expressed proteins and extracellular hydrolytic enzymes that are specifically induced, thereby reducing the analysis to only those proteins that are distinctively up-regulated.

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“…The selected isolates differed from each other with respect to fermentation profiling, substrate spectrum, and each produced a differential quantity of yellow affinity substance (YAS) during growth on cellulose. The positive effect of this YAS on adsorption and binding of cellulolytic complex of anaerobic bacteria during growth on crystalline cellulosic substrates is well known [41, 42]. …”

Section: Resultsmentioning

confidence: 99%

Cellulosic ethanol production via consolidated bioprocessing by a novel thermophilic anaerobic bacterium isolated from a Himalayan hot spring

Singh

Mathur

Tuli

et al. 2017

Biotechnol Biofuels

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BackgroundCellulose-degrading thermophilic anaerobic bacterium as a suitable host for consolidated bioprocessing (CBP) has been proposed as an economically suited platform for the production of second-generation biofuels. To recognize the overall objective of CBP, fermentation using co-culture of different cellulolytic and sugar-fermenting thermophilic anaerobic bacteria has been widely studied as an approach to achieving improved ethanol production. We assessed monoculture and co-culture fermentation of novel thermophilic anaerobic bacterium for ethanol production from real substrates under controlled conditions.ResultsIn this study, Clostridium sp. DBT-IOC-C19, a cellulose-degrading thermophilic anaerobic bacterium, was isolated from the cellulolytic enrichment cultures obtained from a Himalayan hot spring. Strain DBT-IOC-C19 exhibited a broad substrate spectrum and presented single-step conversion of various cellulosic and hemicellulosic substrates to ethanol, acetate, and lactate with ethanol being the major fermentation product. Additionally, the effect of varying cellulose concentrations on the fermentation performance of the strain was studied, indicating a maximum cellulose utilization ability of 10 g L−1 cellulose. Avicel degradation kinetics of the strain DBT-IOC-C19 displayed 94.6% degradation at 5 g L−1 and 82.74% degradation at 10 g L−1 avicel concentration within 96 h of fermentation. In a comparative study with Clostridium thermocellum DSM 1313, the ethanol and total product concentrations were higher by the newly isolated strain on pretreated rice straw at an equivalent substrate loading. Three different co-culture combinations were used on various substrates that presented two-fold yield improvement than the monoculture during batch fermentation.ConclusionsThis study demonstrated the direct fermentation ability of the novel thermophilic anaerobic bacteria on various cellulosic and hemicellulosic substrates into ethanol without the aid of any exogenous enzymes, representing CBP-based fermentation approach. Here, the broad substrate utilization spectrum of isolated cellulolytic thermophilic anaerobic bacterium was shown to be of potential utility. We demonstrated that the co-culture strategy involving novel strains is efficient in improving ethanol production from real substrate.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0756-6) contains supplementary material, which is available to authorized users.

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The effect of yellow affinity substance on cellulases of Ruminococcus flavefaciens

Cited by 16 publications

References 5 publications

Ecological and physiological characterization shows that Fibrobacter succinogenes is important in rumen fiber digestion — Review

Ecological and physiological characterization shows that Fibrobacter succinogenes is important in rumen fiber digestion — Review

Applying theories of microbial metabolism for induction of targeted enzyme activity in a methanogenic microbial community at a metabolic steady state

Cellulosic ethanol production via consolidated bioprocessing by a novel thermophilic anaerobic bacterium isolated from a Himalayan hot spring

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