scholarly journals Cross-feeding between Thauera aminoaromatica and Rhodococcus pyridinivorans drove quinoline biodegradation in a denitrifying bioreactor

2020 ◽  
Author(s):  
Xinxin Wu ◽  
Xiaogang Wu ◽  
Ji Li ◽  
Qiaoyu Wu ◽  
Yiming Ma ◽  
...  
Keyword(s):  
Heterocyclic Compounds ◽  
Removal Rate ◽  
Resting Cells ◽  
Intermediate Metabolites ◽  
End Products ◽  
Initial Oxygen ◽  
Significant Step ◽  
Abundant Taxon ◽  
Specific Amplification ◽  
Microbial Mechanism

AbstractThe complex bacterial community is predominated by several taxa, such as Thauera and Rhodococcus, in a quinoline-degrading denitrifying bioreactor. Yet it remains unclear about how the interactions between the different bacteria mediate the quinoline metabolism in denitrifying condition. In this study, we designed a sequence-specific amplification to guide the isolation of the most predominant bacteria and obtained four strains of Thauera aminoaromatica, the representative of one key member in the bioreactor. Test on these isolates demonstrated that all of them were unable to strive on quinoline but could efficiently degrade 2-hydroxyquinoline, the hypothesized primary intermediate of quinoline catabolism, under nitrate-reducing condition. However, another isolate, Rhodococcus pyridinivorans YF3, corresponding to the second abundant taxon in the same bioreactor, was found to degrade quinoline via 2-hydroxyquinoline. The end products and removal rate of quinoline by isolate YF3 were largely varied with the quantity of available oxygen. Specifically, quinoline could only be converted into 2-hydroxyquinoline without further transformation under the condition with insufficient oxygen, e.g. less than 0.5% initial oxygen in the vials. However, if were aerobically pre-cultured in the medium with quinoline the resting cells of YF3 could anaerobically convert quinoline into 2-hydroxyquinoline. A two-strain consortium constructed with isolates from Thauera (R2) and Rhodococcus (YF3) demonstrated an efficient denitrifying degradation of quinoline. Thus, we experimentally proved that the metabolism interaction based on the 2-hydroxyquinoline cross-feeding between two predominant bacteria constituted the mainstream of quinoline degradation. This work sheds light on the understanding of mechanism of quinoline removal in the denitrifying bioreactor.ImportanceWe experimentally verified the most predominant Thauera sp. was indeed active degrader for the intermediate metabolites and the second abundant taxon Rhodococcus exerted, however, key function for opening the food box for a complex quinoline-degrading community. An ecological guild composed of two isolates was assembled, revealing the different roles of keystone organisms in the microbial community. This study, to our best knowledge, is the first report on the cross feeding between the initial attacker with unprofitable catalysis of reluctant heterocyclic compounds and the second bacterium which then completely degrade the compound transformed by the first bacterium. These results could be a significant step forward towards elucidation of microbial mechanism for quinoline denitrifying degradation.

scholarly journals Cross-Feeding between Members of Thauera spp. and Rhodococcus spp. Drives Quinoline-Denitrifying Degradation in a Hypoxic Bioreactor

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Xinxin Wu ◽  
Xiaogang Wu ◽  
Ji Li ◽  
Qiaoyu Wu ◽  
Yiming Ma ◽  
...  
Keyword(s):  
Removal Rate ◽  
Degradation Mechanism ◽  
Bacterial Species ◽  
Content Type ◽  
Reducing Conditions ◽  
Initial Oxygen ◽  
Oxygen Conditions ◽  
Significant Step ◽  
Abundant Taxon ◽  
Amplification Strategy

ABSTRACT The complex bacterial community in a quinoline-degrading denitrifying bioreactor is predominated by several taxa, such as Thauera and Rhodococcus. However, it remains unclear how the interactions between the different bacteria mediate quinoline metabolism under denitrifying conditions. In this study, we designed a sequence-specific amplification strategy to isolate the most predominant bacteria and obtained four strains of Thauera aminoaromatica, a representative of a key member in the bioreactor. Tests on these isolates demonstrated that all were unable to degrade quinoline but efficiently degraded 2-hydroxyquinoline, the hypothesized primary intermediate of quinoline catabolism, under nitrate-reducing conditions. However, another isolate, Rhodococcus sp. YF3, corresponding to the second most abundant taxon in the same bioreactor, was found to degrade quinoline via 2-hydroxyquinoline. The end products and removal rate of quinoline by isolate YF3 largely varied according to the quantity of available oxygen. Specifically, quinoline could be converted only to 2-hydroxyquinoline without further transformation under insufficient oxygen conditions, e.g., less than 0.5% initial oxygen in the vials. However, resting YF3 cells aerobically precultured in medium with quinoline could anaerobically convert quinoline to 2-hydroxyquinoline. A two-strain consortium constructed with isolates from Thauera (R2) and Rhodococcus (YF3) demonstrated efficient denitrifying degradation of quinoline. Thus, we experimentally verified that the metabolic interaction based on 2-hydroxyquinoline cross-feeding between two predominant bacteria constitutes the main quinoline degradation mechanism. This work uncovers the mechanism of quinoline removal by two cooperative bacterial species existing in denitrifying bioreactors. IMPORTANCE We experimentally verified that the second most abundant taxon, Rhodococcus, played a role in degrading quinoline to 2-hydroxyquinoline, while the most abundant taxon, Thauera, degraded 2-hydroxyquinoline. Metabolites from Thauera further served to provide metabolites for Rhodococcus. Hence, an ecological guild composed of two isolates was assembled, revealing the different roles that keystone organisms play in the microbial community. This report, to the best of our knowledge, is the first on cross-feeding between the initial quinoline degrader and a second bacterium. Specifically, the quinoline degrader (Rhodococcus) did not benefit metabolically from quinoline degradation to 2-hydroxyquinoline but instead benefited from the metabolites produced by the second bacterium (Thauera) when Thauera degraded the 2-hydroxyquinoline. These results could be a significant step forward in the elucidation of the microbial mechanism underlying quinoline-denitrifying degradation.

Full-Scale Study to Treat Hydrogen Sulfide with Biofilter

2013 ◽  
Vol 443 ◽  
pp. 629-633 ◽  
Author(s):  
Chao Zhang ◽  
Bo Fu Li ◽  
Ying He Jiang
Keyword(s):  
Gas Flow ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Removal Rate ◽  
National Level ◽  
Municipal Wastewater Treatment ◽  
Operation Process ◽  
End Products ◽  
Resident Time ◽  
Municipal Wastewater Treatment Plants

With the development of urbanization, the odor from municipal wastewater treatment plants has disturbed the neighborhood and the control of odor has become an urgency research subject. The H2S odor was treated by the biofilter. The removal load of the biofilter, end products of H2S degradation, and operation process were studied in this paper. The results of removal H2S odor with the biofilter were as follows: When the gas flow rate was 1000m3/h (resident time 16.2s) and 1250m3/h (resident time 13.0s), and the inlet concentration of H2S ranged from 1.876 to 34.705mg/m3, the removal rate maintained above 99.92%, and the average outlet concentration was 0.001 mg/m3 which was far lower than the national level of discharge standard. The relationship between removal rate and temperature satisfied with the formula , and for H2S, θ=1.016. Furthermore, the end products of H2S degradation were only sulfate without sulfide. With the increase of sulfate, the removal of H2S was not affected. The study of operating parameters with the biofilter provided the necessary technical support for industrial design and operation control.

scholarly journals Gut microbial catabolism of grape seed flavan-3-ols by human faecal microbiota. Targetted analysis of precursor compounds, intermediate metabolites and end-products

2012 ◽  
Vol 131 (1) ◽  
pp. 337-347 ◽  
Author(s):  
Fernando Sánchez-Patán ◽  
Carolina Cueva ◽  
Maria Monagas ◽  
Gemma E. Walton ◽  
Glenn R. Gibson ◽  
...  
Keyword(s):  
Grape Seed ◽  
Faecal Microbiota ◽  
Intermediate Metabolites ◽  
End Products

The Degradation Efficiency Study of Coke-Wastewater Bacteria by the Exogenous Substrates

2011 ◽  
Vol 183-185 ◽  
pp. 725-728
Author(s):  
Ping Li ◽  
Hong Gang Li ◽  
Ling Zhang ◽  
Fang Ma
Keyword(s):  
Heterocyclic Compounds ◽  
Removal Rate ◽  
Nitrogen Sources ◽  
Ammonia Nitrogen ◽  
Degradation Efficiency ◽  
Reaction Conditions ◽  
Carbon And Nitrogen Sources ◽  
Carbon And Nitrogen ◽  
Coke Wastewater ◽  
Wastewater Bacteria

The coke-wastewater contained all the pollutants which are the aromatic compounds and heterocyclic compounds with benzene ring. Under the normal conditions, it is difficult to obtain good results. By the microbial metabolism of the theory , it is easy to microbial degradation. The use of the primary matrix improves the degradation rate of organic matter .we studied some co-metabolism of carbon and nitrogen sources which affect the bacteria in the degradation of coke-wastewater to remove ammonia and COD. At the same kind of reaction conditions, the removal rate of COD and ammonia nitrogen increase the maximum extent by the addition of glucose and NaNO2. Alkaline substances promote the degradation efficiency.

Biodegradability of some nitrogenous heterocyclic compounds and co-degradation with phenol by denitrifiers in anoxic sludge reactor

2015 ◽  
Vol 72 (3) ◽  
pp. 347-353 ◽  
Author(s):  
Zixing Wang ◽  
Xiaochen Xu ◽  
Fenglin Yang ◽  
Zhongxia Tan ◽  
Jie Chen
Keyword(s):  
Heterocyclic Compounds ◽  
Suspended Solids ◽  
Coal Gasification ◽  
Loading Rate ◽  
Removal Rate ◽  
Carbon Sources ◽  
Organic Loading Rate ◽  
Growth Substrate ◽  
Organic Loading ◽  
Coal Gasification Wastewater

Phenol and nitrogenous heterocyclic compounds (NHCs) are typical organic pollutants in coal gasification wastewater which are difficult to deal with. Unlike phenol, the stable molecular structure of NHCs make them nearly impossible to degrade under aerobic or anaerobic condition. In this paper, biodegradation of phenol and NHCs as carbon sources for denitrification was studied in a laboratory-scale anoxic reactor. Denitrifiers could degrade 490 mg/L phenol and 321.5 mg/L NO3−-N within 12 hours with removal efficiencies of 99.8% and 99.6%, respectively. The inhibition of pyridine on the microbes could be reduced by adding phenol into influent and the experimental results showed that pyridine could be degraded as the sole carbon source with the maximum organic loading rate of 4.38 mg/(g MLSS·h) (MLSS: mixed liquor suspended solids). When phenol was included as a growth substrate, the degradation performance of quinoline and pyrrole was improved due to co-degradation, and removal rate of NHCs increased according with increment of phenol in influent.

scholarly journals Degradation pathway and microbial mechanism of high-concentration thiocyanate in gold mine tailings wastewater

RSC Advances ◽  
2020 ◽  
Vol 10 (43) ◽  
pp. 25679-25684
Author(s):  
Lei Li ◽  
Fanyao Yue ◽  
Yancheng Li ◽  
Aijiang Yang ◽  
Jiang Li ◽  
...  
Keyword(s):  
Mine Tailings ◽  
Removal Rate ◽  
Degradation Pathway ◽  
Gold Mine ◽  
High Concentration ◽  
Gold Mine Tailings ◽  
Microbial Mechanism

Thiocyanate (SCN−) was degraded in COS pathway, and the removal rate was 99.94%. The Thiobacillus played an important role.

Ultrastructure of Melosira resting cell rejuvenation

1984 ◽  
Vol 42 ◽  
pp. 734-735
Author(s):  
C. E. M. Bourne ◽  
L. Sicko-Goad
Keyword(s):  
Electron Microscopy ◽  
Lake Michigan ◽  
Light And Electron Microscopy ◽  
Resting Cells ◽  
Planktonic Diatoms ◽  
Resting Cell ◽  
Vegetative Survival ◽  
Cytological Changes ◽  
Recent Attention ◽  
Freshwater Diatom

Much recent attention has been focused on vegetative survival forms of planktonic diatoms and other algae. There are several reports of extended vegetative survival of the freshwater diatom Melosira in lake sediments. In contrast to those diatoms which form a morphologically distinct resistant spore, Melosira is known to produce physiological resting cells that are indistinguishable in outward morphology from actively growing cells.We used both light and electron microscopy to document and elucidate the sequence of cytological changes during the transition from resting cells to actively growing cells in a population of Melosira granulata from Douglas Lake, Michigan sediments collected in mid-July of 1983.

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