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Thomas, Swapna; Sarfaraz, Sami; Mishra, Lakshmi Chandra; Iyengar, Leela

doi:10.1023/a:1013947722911

Cited by 46 publications

(7 citation statements)

References 16 publications

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“…In several previous studies on defined co-cultures, it was a common strategy to proceed by isolating the dominant members of a mixed enrichment culture and then recombining the isolates in order to reproduce the stability and function of the original microflora [17,21,29,30]. Here, we combined two closely-related strains from geographically distant, albeit similar, habitats, i.e., C. saccharolyticus DSM 8903 and C. kristjanssonii DSM 12137.…”

Section: Discussionmentioning

confidence: 99%

“…Although the approach appears interesting, the stability of these artificial communities is remarkably difficult to achieve for various reasons, as discussed by Weibel [4]. To date, there appears to be only few studies that report on the construction of co-cultures consisting of two or more bacterial species that can stably coexist over a long period of time [17-21]. …”

Section: Introductionmentioning

confidence: 99%

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Stable coexistence of two Caldicellulosiruptor species in a de novo constructed hydrogen-producing co-culture

2010

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BackgroundMixed culture enrichments have been used frequently for biohydrogen production from different feedstock. In spite of the several advantages offered by those cultures, they suffer poor H2 yield. Constructing defined co-cultures of known H2 producers may offer a better performance than mixed-population enrichments, while overcoming some of the limitations of pure cultures based on synergies among the microorganisms involved.ResultsThe extreme thermophiles Caldicellulosiruptor saccharolyticus DSM 8903 and C. kristjanssonii DSM 12137 were combined in a co-culture for H2 production from glucose and xylose in a continuous-flow stirred tank reactor. The co-culture exhibited a remarkable stability over a period of 70 days under carbon-sufficient conditions, with both strains coexisting in the system at steady states of different dilution rates, as revealed by species-specific quantitative PCR assays. The two strains retained their ability to stably coexist in the reactor even when glucose was used as the sole growth-limiting substrate. Furthermore, H2 yields on glucose exceeded those of either organism alone under the same conditions, alluding to a synergistic effect of the two strains on H2 production. A maximum H2 yield of 3.7 mol (mol glucose)-1 was obtained by the co-culture at a dilution rate of 0.06 h-1; a higher yield than that reported for any mixed culture to date. A reproducible pattern of population dynamics was observed in the co-culture under both carbon and non-carbon limited conditions, with C. kristjanssonii outgrowing C. saccharolyticus during the batch start-up phase and prevailing at higher dilution rates. A basic continuous culture model assuming the ability of C. saccharolyticus to enhance the growth of C. kristjanssonii could mimic the pattern of population dynamics observed experimentally and provide clues to the nature of interaction between the two strains. As a proof, the cell-free growth supernatant of C. saccharolyticus was found able to enhance the growth of C. kristjanssonii in batch culture through shortening its lag phase and increasing its maximum biomass concentration by ca. 18%.ConclusionsThis study provides experimental evidence on the stable coexistence of two closely related organisms isolated from geographically-distant habitats under continuous operation conditions, with the production of H2 at high yields. An interspecies interaction is proposed as the reason behind the remarkable ability of the two Caldicellulosiruptor strains to coexist in the system rather than only competing for the growth-limiting substrate.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stable coexistence of two Caldicellulosiruptor species in a de novo constructed hydrogen-producing co-culture

2010

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“…At high concentrations of heavy crude oil degradation percentage did not change and increasing concentration decreased microbial growth and degradation percentage [11]. Usually in biodegradation of hydrocarbons, increase of hydrocarbon concentration raised degraded hydrocarbon and reduced percentage of degradation [24,28-31]; nevertheless increase of concentration was able to decrease [24,25] or increase [31] microbial growth.…”

Section: Discussionmentioning

confidence: 99%

Study on biodegradation of Mazut by newly isolated strain Enterobacter cloacae BBRC10061: improving and kinetic investigation

Khorasani

Mashreghi

Yaghmaei

2013

J Environ Health Sci Engineer

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Mazut as a source content of various hydrocarbons is hard to be degraded and its cracking could turn mazut into useful materials. Nevertheless degradation of mazut by routine methods is too expensive but application of indigenous microorganisms as biocatalysts could be effective and important to lower the costs and expand its consumption. Mazut biodegradation can be improved using various strategies; Therefore in this study newly isolated strain Enterobacter cloacae BBRC 10061 was used in a method of gradual addition of mazut into medium and its results were compared with simple addition method. To investigate degradation of mazut by BBRC 10061, influence of increase of mazut concentration was assayed based on gradual addition method. Also different kinetic models were used to evaluate kinetics of the process. Results showed that gradual addition method has been a beneficial technique for improvement of mazut degradation because bacterial induction to produce biosurfactant and essential enzymes for cracking mazut was higher during process. Although addition of more mazut increased the rate of biodegradation but percentage of degradation decreased. pH of medium decreased during biodegradation period while electric potential increased. Also the biodegradation kinetics was not fitted with the biokinetic models; therefore kinetics of biodegradation of mazut has to be studied by new models.

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“…It can cause sicknesses of liver, kidney or nervous system, if they were taken in for a long time. There is also the possibility of induced lymphosarcoma, lung cancer, colorectal cancer, cervical cancer and other cancers [4,5]. These chlorinated benzene and chlorinated phenols has been posted on the US Environmental Protection Agency (USEPA) website, which are classified as priority control pollutants.…”

Section: Introductionmentioning

confidence: 99%

Analyze the health risk assessment of chlorinated organic pollutants in the water source for food processing in Nanning

Wang¹,

Kong²,

Gao³

et al. 2016

Proceedings of the 2015 4th International Conference on Sustainable Energy and Environmental Engineering

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6 kinds of chlorinated organic pollutants, such as chlorobenzene, 1, 2-dichlorobenzene, 1, 4 -dichlorobenzene, 1,2,4-trichlorobenzene, 2, 4 -dichlorophenol and pentachlorophenol, were analyzed in 5 main water source for 50 food processing companies in Nanning. The health risk assessment of the chlorinated organic pollutants were also studied by the drinking water assessment method of United States Environmental Protection Agency (USEPA). The results showed that all the chlorinated organic pollutants were not detected in the water example, as the concentrations are lower than the detection limit of the instruments. The instrumental detection limit were used as the concentrations of the pollutants to value the health risk assessment, and the results showed that the hazard index (HI) of total non-carcinogenic risks of the pollutants were below 1.0, suggesting that the water posed negligible health risk on local residents.

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Untitled

Cited by 46 publications

References 16 publications

Stable coexistence of two Caldicellulosiruptor species in a de novo constructed hydrogen-producing co-culture

Stable coexistence of two Caldicellulosiruptor species in a de novo constructed hydrogen-producing co-culture

Study on biodegradation of Mazut by newly isolated strain Enterobacter cloacae BBRC10061: improving and kinetic investigation

Analyze the health risk assessment of chlorinated organic pollutants in the water source for food processing in Nanning

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