Biological Cr(VI) reduction in indigenous sludge cultures from Gauteng, South Africa

2006 ◽  
Vol 54 (10) ◽  
pp. 177-184
Author(s):  
P.E. Molokwanne ◽  
E.M.N. Chirwa
Keyword(s):  
Pure Culture ◽  
Reduction Rate ◽  
Packed Bed ◽  
Bacillus Sp ◽  
Packed Bed Bioreactor ◽  
Toxic Compounds ◽  
Primary Sludge ◽  
Reduction Activity ◽  
Pure Cultures ◽  
Reducing Bacteria

The Cr(VI) reducing capability of an acclimated indigenous culture cultivated from primary sludge was evaluated in batch and packed-bed bioreactor systems. Performance evaluation was carried out in unmodified cultures, cultures modified by substituting terminal organisms in the consortium by a known Cr(VI)-reducing organism (Escherichia coli ATCC 33456), and pure cultures of Cr(VI)-reducing organisms. A high Cr(VI) reduction rate was observed in modified cultures and in the pure culture of the Cr(VI)-reducing bacteria (Bacillus sp.). Furthermore, the Bacillus sp. pure culture outperformed both the unmodified and modified consortium cultures in reducing Cr(VI). Abiotic Cr(VI) reduction activity was evaluated in heat-killed and azide (N3−) inactivated control cultures. No significant Cr(VI) reduction was observed in the controls. This study is part of the continuing research to identify synergistic culture systems for treating toxic compounds from polluted environments.

scholarly journals Implications of Limited Thermophilicity of Nitrite Reduction for Control of Sulfide Production in Oil Reservoirs

2016 ◽  
Vol 82 (14) ◽  
pp. 4190-4199 ◽  
Author(s):  
Tekle Tafese Fida ◽  
Chuan Chen ◽  
Gloria Okpala ◽  
Gerrit Voordouw
Keyword(s):  
Nitrate Reduction ◽  
Nitrite Reduction ◽  
Oil Fields ◽  
Microbial Consortia ◽  
Subsequent Reduction ◽  
Content Type ◽  
Reduction Activity ◽  
Pure Cultures ◽  
Nitrate And Nitrite ◽  
Reducing Bacteria

ABSTRACTNitrate reduction to nitrite in oil fields appears to be more thermophilic than the subsequent reduction of nitrite. Concentrated microbial consortia from oil fields reduced both nitrate and nitrite at 40 and 45°C but only nitrate at and above 50°C. The abundance of thenirSgene correlated with mesophilic nitrite reduction activity.ThaueraandPseudomonaswere the dominant mesophilic nitrate-reducing bacteria (mNRB), whereasPetrobacterandGeobacilluswere the dominant thermophilic NRB (tNRB) in these consortia. The mNRBThauerasp. strain TK001, isolated in this study, reduced nitrate and nitrite at 40 and 45°C but not at 50°C, whereas the tNRBPetrobactersp. strain TK002 andGeobacillussp. strain TK003 reduced nitrate to nitrite but did not reduce nitrite further from 50 to 70°C. Testing of 12 deposited pure cultures of tNRB with 4 electron donors indicated reduction of nitrate in 40 of 48 and reduction of nitrite in only 9 of 48 incubations. Nitrate is injected into high-temperature oil fields to prevent sulfide formation (souring) by sulfate-reducing bacteria (SRB), which are strongly inhibited by nitrite. Injection of cold seawater to produce oil creates mesothermic zones. Our results suggest that preventing the temperature of these zones from dropping below 50°C will limit the reduction of nitrite, allowing more effective souring control.IMPORTANCENitrite can accumulate at temperatures of 50 to 70°C, because nitrate reduction extends to higher temperatures than the subsequent reduction of nitrite. This is important for understanding the fundamentals of thermophilicity and for the control of souring in oil fields catalyzed by SRB, which are strongly inhibited by nitrite.

scholarly journals Removal of aqueous benzene in the immobilized batch and continuous packed bed bioreactor by isolated Bacillus sp. M1

2016 ◽  
Vol 2 ◽  
pp. S87-S95 ◽  
Author(s):  
M.K. Kureel ◽  
S.R. Geed ◽  
B.S. Giri ◽  
A.K. Shukla ◽  
B.N. Rai ◽  
...  
Keyword(s):  
Packed Bed ◽  
Bacillus Sp ◽  
Packed Bed Bioreactor

scholarly journals Sulfate-Reducing Bacteria Methylate Mercury at Variable Rates in Pure Culture and in Marine Sediments

2000 ◽  
Vol 66 (6) ◽  
pp. 2430-2437 ◽  
Author(s):  
Jeffrey K. King ◽  
Joel E. Kostka ◽  
Marc E. Frischer ◽  
F. Michael Saunders
Keyword(s):  
Sulfate Reduction ◽  
Marine Sediments ◽  
Marine Sediment ◽  
Pure Culture ◽  
Sulfate Reducing Bacteria ◽  
Mercury Methylation ◽  
Sulfate Reducing ◽  
The Family ◽  
Pure Cultures ◽  
Reducing Bacteria

ABSTRACT Differences in methylmercury (CH3Hg) production normalized to the sulfate reduction rate (SRR) in various species of sulfate-reducing bacteria (SRB) were quantified in pure cultures and in marine sediment slurries in order to determine if SRB strains which differ phylogenetically methylate mercury (Hg) at similar rates. Cultures representing five genera of the SRB (Desulfovibrio desulfuricans, Desulfobulbus propionicus,Desulfococcus multivorans, Desulfobacter sp. strain BG-8, and Desulfobacterium sp. strain BG-33) were grown in a strictly anoxic, minimal medium that received a dose of inorganic Hg 120 h after inoculation. The mercury methylation rates (MMR) normalized per cell were up to 3 orders of magnitude higher in pure cultures of members of SRB groups capable of acetate utilization (e.g., the family Desulfobacteriaceae) than in pure cultures of members of groups that are not able to use acetate (e.g., the family Desulfovibrionaceae). Little or no Hg methylation was observed in cultures of Desulfobacterium orDesulfovibrio strains in the absence of sulfate, indicating that Hg methylation was coupled to respiration in these strains. Mercury methylation, sulfate reduction, and the identities of sulfate-reducing bacteria in marine sediment slurries were also studied. Sulfate-reducing consortia were identified by using group-specific oligonucleotide probes that targeted the 16S rRNA molecule. Acetate-amended slurries, which were dominated by members of the Desulfobacterium and Desulfobacter groups, exhibited a pronounced ability to methylate Hg when the MMR were normalized to the SRR, while lactate-amended and control slurries had normalized MMR that were not statistically different. Collectively, the results of pure-culture and amended-sediment experiments suggest that members of the family Desulfobacteriaceae have a greater potential to methylate Hg than members of the familyDesulfovibrionaceae have when the MMR are normalized to the SRR. Hg methylation potential may be related to genetic composition and/or carbon metabolism in the SRB. Furthermore, we found that in marine sediments that are rich in organic matter and dissolved sulfide rapid CH3Hg accumulation is coupled to rapid sulfate reduction. The observations described above have broad implications for understanding the control of CH3Hg formation and for developing remediation strategies for Hg-contaminated sediments.

Bioreactor for Accurately Assessing Biocide Effectiveness in Controlling Biogenic Souring in Mature Oil Wells

SPE Journal ◽  
2018 ◽  
Vol 23 (05) ◽  
pp. 1809-1816
Author(s):  
J. A. Ferreira ◽  
P. F. Almeida ◽  
J.. Nunes dos Santos ◽  
I. C. Sampaio ◽  
L.. França Figueirêdo ◽  
...  
Keyword(s):  
Dynamic System ◽  
Packed Bed ◽  
Sulfate Reducing Bacteria ◽  
Oil Wells ◽  
Neem Oil ◽  
Packed Bed Bioreactor ◽  
Recovery Rates ◽  
Sulfate Reducing ◽  
Batch Testing ◽  
Reducing Bacteria

Summary Biocide injections are used for controlling biological souring in mature oil wells, but unpredictable results of such practices are also frequently reported. To address this problem, this research aimed to quantify the effect of four new biocides, and one commonly used biocide, within a dynamic system (packed-bed bioreactor) without using batch testing. The bioreactor was operated for 591 days, and the results showed that sulfate-reducing-bacteria (SRB) activity could recover within a period that varied from 15 to 60 days. Neem-oil (NO) (1.5% vol/vol) and 3,5-dimethyl-1,3,5-thiadiazinane-2-thione (Dazomet, DZ) (0.5% vol/vol) were the most efficient in controlling SRB activity. The tests showed that the mechanistic interaction controlling souring is not only associated with the compounds’ toxicity. Immiscible biocides not only killed cells, but they also can control SRB-recovery rates after the injection of biocides.

Selenium Uptake by a Coal Mine Wetland Sediment

2003 ◽  
Vol 38 (3) ◽  
pp. 483-497 ◽  
Author(s):  
Susan A. Baldwin ◽  
Al Henry Hodaly
Keyword(s):  
Growth Medium ◽  
Coal Mine ◽  
Mine Waste ◽  
Reduction Rate ◽  
Plant Debris ◽  
Bacteria Growth ◽  
Sulfate Reducing ◽  
Selenium Uptake ◽  
Negative Effect ◽  
Reducing Bacteria

Abstract Sediment from a wetland receiving runoff from a coal mine waste dump in the Elk River Valley of southeast British Columbia was assessed for potential selenium uptake. Selenite [SeO32-, Se(IV)] was found to adsorb to the washed sediment at pH 7 to 8, whereas no selenate [SeO42-, Se(VI)] was adsorbed, in the concentration range of 8 to 225 μg L-1 Se as selenite or selenate. Sulfate- and selenate-reducing bacterial activity was detected in the sediment. In the presence of sulfate-reducing bacteria growth medium, Se as selenate was reduced from 619(±53) μg L-1 to 15(±0.7) μg L-1, and in the presence of selenate-reducing bacteria growth medium, Se as selenate was reduced from 364(±66) mg L-1 to 22(±10) mg L-1. Semi-continuous microcosms containing sediment overlaid with selenate (500 μg L-1 Se) and sulfate (0.9 g L-1) containing water were amended with plant debris from the site or nutrients (lactate and fertilizer). Potential selenate reduction rate (0.76 h-1) was highest in the unamended microcosms. Amendment with plant debris from the site had a negative effect on selenate reduction rate in the short term (after one hour) and a positive effect on Se removal in the long term (after one week). This study suggests that wetland sediments at the mine site may be important sinks for Se.

Three-dimensional CFD simulation of anaerobic reactions in a continuous packed-bed bioreactor

2021 ◽  
Author(s):  
Sasan Zarei ◽  
Seyyed Mohammad Mousavi ◽  
Teimour Amani ◽  
Mehrdad Khamforoush ◽  
Arezou Jafari
Keyword(s):  
Cfd Simulation ◽  
Three Dimensional ◽  
Packed Bed ◽  
Packed Bed Bioreactor

Toxicity and recalcitrant compound removal from bleaching pulp plant effluents by an integrated system: anaerobic packed-bed bioreactor and ozone

2010 ◽  
Vol 61 (1) ◽  
pp. 199-205 ◽  
Author(s):  
T. R. Chaparro ◽  
C. M. Botta ◽  
E. C. Pires
Keyword(s):  
Pulp Mill ◽  
Packed Bed ◽  
Ultraviolet Absorption ◽  
Integrated System ◽  
Packed Bed Bioreactor ◽  
Cellulose Pulp ◽  
Adsorbable Organic Halides ◽  
Organic Halides ◽  
Before And After ◽  
Absorption Measurements

Effluents originated in cellulose pulp manufacturing processes are usually toxic and recalcitrant, specially the bleaching effluents, which exhibit high contents of aromatic compounds (e.g. residual lignin derivates). Although biological processes are normally used, their efficiency for the removal of toxic lignin derivates is low. The toxicity and recalcitrance of a bleached Kraft pulp mill were assessed through bioassays and ultraviolet absorption measurements, i.e. acid soluble lignin (ASL), UV280, and specific ultraviolet absorption (SUVA), before and after treatment by an integrated system comprised of an anaerobic packed-bed bioreactor and oxidation step with ozone. Furthermore, adsorbable organic halides (AOX) were measured. The results demonstrated not only that the toxic recalcitrant compounds can be removed successfully using integrated system, but also the ultraviolet absorption measurements can be an interesting control-parameter in a wastewater treatment.

Production of HIV-1 gp120 in Packed-Bed Bioreactor Using the Vaccinia Virus/T7 Expression System

2000 ◽  
Vol 16 (5) ◽  
pp. 744-750 ◽  
Author(s):  
Y.-C. Hu ◽  
J. Kaufman ◽  
M.W. Cho ◽  
H. Golding ◽  
J. Shiloach
Keyword(s):  
Vaccinia Virus ◽  
Expression System ◽  
Packed Bed ◽  
Packed Bed Bioreactor ◽  
T7 Expression System ◽  
Hiv 1
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