Quantification of Microorganisms Involved in Cemented Layer Formation in Sulfidic Mine Waste Tailings (Freiberg, Saxony, Germany)

2007 ◽  
Vol 20-21 ◽  
pp. 481-484 ◽  
Author(s):  
Dagmar Kock ◽  
Torsten Graupner ◽  
Dieter Rammlmair ◽  
Axel Schippers
Keyword(s):  
Extracellular Polymeric Substances ◽  
Mine Waste ◽  
Mineral Weathering ◽  
Most Probable Number ◽  
Layer Formation ◽  
Probable Number ◽  
Cell Numbers ◽  
Erosion Processes ◽  
Mineral Phases

Cemented layers predominantly consisting of gels/poorly crystalline mineral phases have been formed as a consequence of mineral weathering in sulfidic tailings near Freiberg, Saxony, Germany. These layers function as natural attenuation barrier for toxic compounds and reduce oxidation and erosion processes of tailings surfaces. Quantitative molecular biological and cultivation methods were applied to investigate the role of microorganisms for mineral weathering and cemented layer formation. High resolution depth profiles of numbers of microorganisms showed maximal cell numbers in the oxidation zone where cemented layers had been formed. Highest total cell numbers of >109 cells g-1 dry weight (dw) were detected by SybrGreen direct counting. Using quantitative real-time PCR (Q-PCR) between 107 and 109 Bacteria g-1 dw and up to 108 Archaea g-1 dw were determined. As well high numbers of cultivable and living Bacteria could be detected by MPN (most probable number) for Fe(II)- and S-oxidizers and CARD-FISH (catalyzed reporter deposition - fluorescence in situ hybridization). Overall, the high numbers of microorganisms determined with various quantification techniques argue for a significant role of microorganisms in cemented layer formation due to microbial mineral weathering. It is hypothesized that EPS (extracellular polymeric substances) mediate the formation of secondary mineral phases.

Microbial Community Analysis inside a Biooxidation Heap for Gold Recovery in Equador

2017 ◽  
Vol 262 ◽  
pp. 135-138 ◽  
Author(s):  
Carlos L. Aspiazu ◽  
Paulina Aguirre ◽  
Sabrina Hedrich ◽  
Axel Schippers
Keyword(s):  
Microbial Community ◽  
Fine Fraction ◽  
Community Analysis ◽  
Gold Recovery ◽  
Microbial Community Analysis ◽  
Most Probable Number ◽  
Rrna Gene ◽  
Probable Number ◽  
Cell Numbers ◽  
Cell Counts

In a mine owned by the company Orenas S.A. (Equador), a biooxidation process for gold recovery has been developed. Refractory gold ore was crushed, milled and 500 ton of flotation concentrate was agglomerated by coating a support rock. This was piled up on a liner and the biooxidation process in the heap of 35x25x6 m3 was run for approximately 150 days. The oxidized material was subsequently removed for further processing. An outcrop allowed for depth dependent sampling of altogether 36 samples at three sites over the complete depth of 6 m. The fine fraction was removed from the host rock and sent to the laboratory for analysis of the microbial community. The pH ranged between 2.2 and 2.9. Total cell counts determined via counting under a fluorescence microscope after SYBR Green staining indicated a high microbial colonialization of the heap in all depths between 106 to 109 cells per g concentrate, however the highest cell numbers were mainly found in the upper 50 cm. Most-probable-number determination of living, acidophilic iron (II)-oxidizers for one site also revealed a decrease of cell numbers with depth (between 104 to 108 cells per g concentrate). Further molecular analyses of the community composition based on extracted DNA and 16S rRNA gene analyses by TRFLP and qPCR revealed a complex archaeal and bacterial community within the heap. It can be stated that an active community of acidophiles runs the biooxidation process in all sampled parts of the heap.

scholarly journals Evidence for Microbial Fe(III) Reduction in Anoxic, Mining-Impacted Lake Sediments (Lake Coeur d'Alene, Idaho)

2000 ◽  
Vol 66 (1) ◽  
pp. 154-162 ◽  
Author(s):  
David E. Cummings ◽  
Anthony W. March ◽  
Benjamin Bostick ◽  
Stefan Spring ◽  
Frank Caccavo ◽  
...  
Keyword(s):  
Iron Reduction ◽  
Dry Weight ◽  
Most Probable Number ◽  
Probable Number ◽  
Coeur D'alene ◽  
Reduction Of Iron ◽  
Study Support ◽  
Reducing Bacteria ◽  
Microbiological Data

ABSTRACT Mining-impacted sediments of Lake Coeur d'Alene, Idaho, contain more than 10% metals on a dry weight basis, approximately 80% of which is iron. Since iron (hydr)oxides adsorb toxic, ore-associated elements, such as arsenic, iron (hydr)oxide reduction may in part control the mobility and bioavailability of these elements. Geochemical and microbiological data were collected to examine the ecological role of dissimilatory Fe(III)-reducing bacteria in this habitat. The concentration of mild-acid-extractable Fe(II) increased with sediment depth up to 50 g kg−1, suggesting that iron reduction has occurred recently. The maximum concentrations of dissolved Fe(II) in interstitial water (41 mg liter−1) occurred 10 to 15 cm beneath the sediment-water interface, suggesting that sulfidogenesis may not be the predominant terminal electron-accepting process in this environment and that dissolved Fe(II) arises from biological reductive dissolution of iron (hydr)oxides. The concentration of sedimentary magnetite (Fe3O4), a common product of bacterial Fe(III) hydroxide reduction, was as much as 15.5 g kg−1. Most-probable-number enrichment cultures revealed that the mean density of Fe(III)-reducing bacteria was 8.3 × 105 cells g (dry weight) of sediment−1. Two new strains of dissimilatory Fe(III)-reducing bacteria were isolated from surface sediments. Collectively, the results of this study support the hypothesis that dissimilatory reduction of iron has been and continues to be an important biogeochemical process in the environment examined.

A Novel Method for the Reduction of Numbers of Listeria monocytogenes Cells by Freezing in Combination with an Essential Oil in Bacteriological Media

2003 ◽  
Vol 66 (3) ◽  
pp. 390-395 ◽  
Author(s):  
HAYDEN K. CRESSY ◽  
ALISTAIR R. JERRETT ◽  
CAROLYN M. OSBORNE ◽  
PHIL J. BREMER
Keyword(s):  
Listeria Monocytogenes ◽  
Most Probable Number ◽  
Polysorbate 80 ◽  
Bactericidal Action ◽  
Freezing And Thawing ◽  
Probable Number ◽  
Freeze Thaw ◽  
Cell Numbers ◽  
Low Concentrations ◽  
Novel Method

The use of multiple freeze (−20°C)–thaw cycles in combination with isoeugenol and polysorbate 80 was investigated as a method for the reduction of numbers of Listeria monocytogenes cells in a bacteriological medium. Three freeze (1 h, −20°C)–thaw cycles in the presence of isoeugenol at concentrations of 0, 100, and 300 ppm resulted in average L. monocytogenes reductions of 0.69, 2.65, and 3.3 log10 MPN (most probable number) per ml, respectively. Increasing the number of freeze–thaw cycles further decreased cell numbers, with reductions of nearly 5 log10 MPN/ml being obtained with six freeze-thaw cycles. Freeze–thaw cycles were effective in reducing cell numbers at isoeugenol concentrations down to 25 ppm. Rapid freezing rates with liquid nitrogen were found to be less effective in reducing numbers of L. monocytogenes cells. Two rapid freeze–thaw cycles in the presence of 100 ppm isoeugenol and polysorbate 80 resulted in a reduction of 1.45 log10 MPN/ml. Two freezing (−20°C) cycles involving slow freezing and thawing rates with samples being held frozen for 6 h for each cycle resulted in reductions larger than those obtained with faster freezing rates. It was found that complete thawing in freeze-thaw cycles was not necessary to achieve bactericidal action. The application of multiple freeze-thaw cycles in combination with low concentrations of isoeugenol could effectively reduce numbers of L. monocytogenes cells in bacteriological media.

scholarly journals Risk of Listeria monocytogenes Contamination of Raw Ready-To-Eat Seafood Products Available at Retail Outlets in Japan

2010 ◽  
Vol 76 (10) ◽  
pp. 3383-3386 ◽  
Author(s):  
Satoko Miya ◽  
Hajime Takahashi ◽  
Tatsuya Ishikawa ◽  
Tateo Fujii ◽  
Bon Kimura
Keyword(s):  
Listeria Monocytogenes ◽  
Most Probable Number ◽  
Infection Model ◽  
Probable Number ◽  
Cell Numbers ◽  
Regulatory Guidelines ◽  
Retail Outlets ◽  
Seafood Products ◽  
Storage Temperatures ◽  
Fish Roe

ABSTRACT Examination of Listeria monocytogenes prevalence among ready-to-eat foods in Japan revealed frequent (5.7 to 12.1%) contamination of minced tuna and fish roe products, and the isolates had the same virulence levels as clinical isolates in terms of invasion efficiency and infectivity in cell cultures and a murine infection model, respectively. Premature stop codons in inlA were infrequent (1 out of 39 isolates). Cell numbers of L. monocytogenes in minced tuna and salmon roe increased rapidly under inappropriate storage temperatures (from a most probable number [MPN] of 100 to 101/g to an MPN of 103 to 104/g over the course of 2 days at 10°C). Thus, regulatory guidelines are needed for acceptable levels of L. monocytogenes in these foods.

scholarly journals Influence of Modified Atmosphere Packaging on the Survival of Salmonella Enteritidis PT 8 on the Surface of Chilled Chicken Legs

2010 ◽  
Vol 79 (9) ◽  
pp. S127-S132 ◽  
Author(s):  
Radka Hulánková ◽  
Gabriela Bořilová ◽  
Iva Steinhauserová
Keyword(s):  
Salmonella Enteritidis ◽  
Modified Atmosphere Packaging ◽  
Most Probable Number ◽  
Modified Atmosphere ◽  
Probable Number ◽  
Wildtype Strain ◽  
Cell Numbers ◽  
Modified Atmospheres ◽  
Natural Microflora ◽  
Chicken Legs

The aim of this study was to find whether low numbers of Salmonella in the presence of natural microflora will survive on the surface of chicken legs stored in 30% CO2/70% N2 and 20% CO2/80% O2. In four experiments, a total of 240 pieces of chicken leg were inoculated with a Salmonella Enteritidis, PT 8, wildtype strain resulting in initial concentrations of approximately 4 log, 2.5 log, 1.5 log and 0.5 log cells per piece and kept under selected modified atmospheres for 14 days. Counts of Salmonella were determined by the Most Probable Number method (MPN) at days 0, 3, 7, 10 and 14 of storage. No significant increase or decrease in Salmonella numbers was observed in the atmosphere of 20% CO2/80% O2. In the atmosphere of 30% CO2/70% N2 there was a significant decrease in cell numbers at days 10 and 14; however, this decrease was proved only in experiments with an initial Salmonella concentration of 4 log and 1.5 log cells per piece. We proved that even low numbers of S. Enteritidis in the presence of natural microflora survive well on the surface of poultry stored at 3 °C in both modified atmospheres we tested. In the case of temperature abuse even products with low initial numbers of Salmonella may constitute a health risk for consumers.

Prevalence and Number of Salmonella in Irish Retail Pork Sausages†

2004 ◽  
Vol 67 (9) ◽  
pp. 1834-1839 ◽  
Author(s):  
C. BOUGHTON ◽  
F. C. LEONARD ◽  
J. EGAN ◽  
G. KELLY ◽  
P. O'MAHONY ◽  
...  
Keyword(s):  
Phage Type ◽  
Control Program ◽  
Multidrug Resistant ◽  
Most Probable Number ◽  
Probable Number ◽  
Pork Sausage ◽  
Pork Industry ◽  
Phage Types ◽  
Pork Sausages

A national Salmonella control program in the pork industry was enacted in Ireland in August 2002. This study was undertaken as part of a larger project investigating the role of pork as a source of human salmonellosis in Ireland. The objective of this survey was to assess the prevalence of Salmonella in Irish pork sausage at retail level. Samples, comprising branded prepacked sausages and loose sausages from supermarket meat counters and butcher shops, were collected from selected retail sites in four cities from October to December 2001 and from June to August 2002. A three-tube most-probable-number method was used to enumerate Salmonella in a selected number of samples that were positive by enrichment. Salmonella serotypes were detected in 4.4 and 1.7% of samples at each of the respective sampling periods, a level similar to those reported in other U.S. and U.K. studies. Isolates were characterized by serotype, phage type, and antimicrobial susceptibility. Eighteen (70%) were resistant to at least one antimicrobial, and 15 (58%) were resistant to four or more antimicrobials. Most of the isolates exhibited resistance to tetracycline. Five different phage types were detected. DT104 was the predominant phage type among Salmonella Typhimurium isolates. This study revealed that multidrug-resistant salmonellae are present in a proportion of Irish sausages and that further risk analysis work is necessary in order to quantify the risk posed to public health.

Analysis of Coliform and Colifecal Total Pollution Test on Various Types of Drinking Water Using the MPN (Most Probable Number) Method

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Wanda Aulya ◽  
Fadhliani Fadhliani ◽  
Vivi Mardina
Keyword(s):  
Drinking Water ◽  
Fecal Coliform ◽  
Pathogenic Bacteria ◽  
Microbiological Quality ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Inspection Method ◽  
Sample Number ◽  
Probable Number ◽  
Fecal Coliform Bacteria

Water is the main source for life and also the most severe substance caused by pollution. The mandatory parameters for determining microbiological quality of drinking water are total non-fecal Coliform bacteria and Coliform fecal (Escherichia coli). Coliform bacteria are a group of microorganisms commonly used as indicators, where these bacteria can be a signal to determine whether a water source has been contaminated by bacteria or not, while fecal Coliform bacteria are indicator bacteria polluting pathogenic bacteria originating from human feces and warm-blooded animals (mammals) . The water inspection method in this study uses the MPN (Most Probable Number) method which consists of 3 tests, namely, the presumption test, the affirmation test, and the reinforcement test. The results showed that of 15 drinking water samples 8 samples were tested positive for Coliform bacteria with the highest total bacterial value of sample number 1, 15 (210/100 ml), while 7 other samples were negative. From 8 positive Coliform samples only 1 sample was stated to be negative fecal Coliform bacteria and 7 other samples were positive for Coliform fecal bacteria with the highest total bacterial value of sample number 1 (210/100 ml).

Cemaran Eshericia coli dalam makanan laut yang beredar di pasar tradisional Kota Pontian

2015 ◽  
Vol 1 (1) ◽  
pp. 44
Author(s):  
Rafika Sari ◽  
Pratiwi Apridamayanti
Keyword(s):  
Most Probable Number ◽  
Probable Number

Latar Belakang: Makanan laut merupakan salah satu jenis makanan yang banyak dikonsumsi oleh masyarakat selain sebagai komoditi ekspor. Mengkonsumsi makanan laut yang telah terkontaminasi bakteri hidup atau toksin yang dihasilkannya dapat menyebabkan keracunan makanan. Tujuan penelitian ini adalah untuk mengetahui adanya kontaminasi bakteri koliform E.coli sebagai indikator pencemaran pada makanan laut dan memberikan informasi kelayakan dan keamanan konsumsi dari makanan laut di dua pasar tradisional terbesar di daerah Pontianak. Metode: Sampel yang digunakan adalah ikan, sotong dan udang. Penelitian terhadap sampel dilakukan menggunakan uji Most Probable Number (MPN) yang dilengkapi dengan uji biokimia untuk mengidentifikasi jenis bakteri pada sampel melalui penanaman bakteri pada media agar Lactose Broth (LB) dan Briliant Green Lactose Bile Broth (BGLB). Hasil: Hasil penelitian menunjukkan bakteri koliform E.coli terdeteksi pada 100% sampel dengan nilai MPN yang tidak memenuhi kriteria kelayakan konsumsi, yakni >3/g. Kesimpulan: Makanan yang ada tidak memenuhi kriteria kelayakan konsumsi.

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