scholarly journals Starvation Improves Survival of Bacteria Introduced into Activated Sludge

2000 ◽  
Vol 66 (9) ◽  
pp. 3905-3910 ◽  
Author(s):  
Kazuya Watanabe ◽  
Mariko Miyashita ◽  
Shigeaki Harayama
Keyword(s):  
Population Density ◽  
Cell Surface ◽  
Activated Sludge ◽  
Ralstonia Eutropha ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Luria Bertani ◽  
Exponential Growth Phase ◽  
Degrading Bacterium ◽  
Metabolic Activities

ABSTRACT A phenol-degrading bacterium, Ralstonia eutropha E2, was grown in Luria-Bertani (LB) medium or in an inorganic medium (called MP) supplemented with phenol and harvested at the late-exponential-growth phase. Phenol-acclimated activated sludge was inoculated with the E2 cells immediately after harvest or after starvation in MP for 2 or 7 days. The densities of the E2 populations in the activated sludge were then monitored by quantitative PCR. The E2 cells grown on phenol and starved for 2 days (P-2 cells) survived in the activated sludge better than those treated differently: the population density of the P-2 cells 7 days after their inoculation was 50 to 100 times higher than the population density of E2 cells without starvation or that with 7-day starvation. LB medium-grown cells either starved or nonstarved were rapidly eliminated from the sludge. The P-2 cells showed a high cell surface hydrophobicity and retained metabolic activities. Cells otherwise prepared did not have one of these two features. From these observations, it is assumed that hydrophobic cell surface and metabolic activities higher than certain levels were required for the inoculated bacteria to survive in the activated sludge. Reverse transcriptase PCR analyses showed that the P-2 cells initiated the expression of phenol hydroxylase within 1 day of their inoculation into the sludge. These results suggest the utility of a short starvation treatment for improving the efficacy of bioaugumentation.

Cell surface and exopolymer characterization of laboratory stabilized activated sludge from a beverage bottling plant

2001 ◽  
Vol 43 (6) ◽  
pp. 175-184 ◽  
Author(s):  
S. M. Boyette ◽  
J. M. Lovett ◽  
W. G. Gaboda ◽  
J. A. Soares
Keyword(s):  
Cell Surface ◽  
Activated Sludge ◽  
Surface Charge ◽  
Electrophoretic Mobility ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Food Sources ◽  
Colloid Titration ◽  
High Concentrations

Fermentor-stabilized activated sludge from an industrial beverage bottling plant was grown on three different food sources: normal plant wastewater, plant wastewater containing high sucrose concentrations, and a synthetic glucose-based feed stock. Surface charge, hydrophobicity, and exopolysaccharide composition were measured on the stabilized bacterial flocs. Cell surface charge was measured by electrophoretic mobility, dye exchange titration, and a standard colloid titration, while cell hydrophobicity was determined using the bacterial adhesion to hydrocarbons (BATH) test. Exopolysaccharide profiles were determined by measuring concentrations of glucose, galactose, mannose, glucuronic, and galacturonic acids in digested exopolymer extractions using HPLC. Changes in the physical surface properties of the bacteria and the chemical composition of the extracted exopolymers were correlated with differences in the three food sources. Cell surface hydrophobicity was similar for cultures grown on different plant wastewaters, while the culture grown on synthetic food produced less floc hydrophobicity. Electrophoretic mobility measurements, charge titrations, and dye exchange titrations showed different total surface charge as well as varying charge availability. Additionally, total surface charge and total exopolysaccharide concentrations appeared less dependent on food source than the food-to-mass ratio. High concentrations of biodegradable food produced dispersed growth and high concentrations of exopolysaccharides that contributed to poor settling.

Influence of oxygen limitation on the cell surface properties of bacteria from activated sludge

1998 ◽  
Vol 37 (4-5) ◽  
pp. 349-352 ◽  
Author(s):  
R. Palmgren ◽  
F. Jorand ◽  
P. H. Nielsen ◽  
J. C. Block
Keyword(s):  
Cell Surface ◽  
Activated Sludge ◽  
Surface Properties ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Growth Conditions ◽  
Oxygen Limitation ◽  
Cell Surface Properties ◽  
Number Of Factors ◽  
Math Test

Cell surface hydrophobicity is believed to be important to flocculation in activated sludge and biofilm systems. Optimization of these processes includes changes in the growth conditions of the bacteria. A number of factors influence cell surface hydrophobicity. The influence of oxygen on the cell surface hydrophobicity of 4 bacteria isolated from activated sludge was tested. The bacteria were grown in batch cultures with and without oxygen limitation. It was found that oxygen limitation generally caused a lowering of the cell surface hydrophobicity. The study also showed that there are many difficulties in measuring cell surface hydrophobicity since other cell surface properties, such as surface charge, influence the measurement methods. The MATH test was employed to establish how assay conditions influenced the results.

Test parameters and cell chain length of Streptococcus thermophilus affect the microbial adhesion to hydrocarbons assay: a methodical approach

2019 ◽  
Vol 366 (12) ◽  
Author(s):  
Carsten Nachtigall ◽  
Carmen Weber ◽  
Sandra Rothenburger ◽  
Doris Jaros ◽  
Harald Rohm
Keyword(s):  
Cell Surface ◽  
Hydrophobic Interactions ◽  
Cell Surface Hydrophobicity ◽  
Streptococcus Thermophilus ◽  
Surface Hydrophobicity ◽  
Exponential Growth Phase ◽  
Microbial Adhesion ◽  
Test Parameters ◽  
Math Test ◽  
The Impact

ABSTRACT The microbial adhesion to hydrocarbons (MATH) test is one of the most common method to determine the hydrophobicity of cell surfaces. Despite its prevalence, no standard test parameters are used in literature, making a direct comparison of data almost impossible. Criticism also focuses on test parameters that may mask hydrophobic interactions and hence lead to erroneous test results. We methodically investigated the impact of different MATH test parameters on the calculation of the cell surface hydrophobicity of Streptococcus thermophilus, a widespread exopolysaccharide-producing lactic acid bacterium used in the production of fermented milk products. Besides composition and ionic strength of the buffer used for cell re-suspension, we observed a pronounced time dependency of the turbidity of the cell suspension during phase separation due to sedimentation and/or cell lysis. A new modification of the MATH assay was applied to enable the determination of cell surface hydrophobicity of long chain-forming bacteria. As the cell surface hydrophobicity was not altered during exponential growth phase, we assume that the cell surface and its capsular exopolysaccharide layer are not changed during cultivation.

scholarly journals Biodegradation of Petroleum Hydrocarbons by Bacillus subtilis BL-27, a Strain with Weak Hydrophobicity

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3021 ◽  
Author(s):  
Dan Wang ◽  
Jiahui Lin ◽  
Junzhang Lin ◽  
Weidong Wang ◽  
Shuang Li
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Cell Surface ◽  
Petroleum Hydrocarbons ◽  
Cell Surface Hydrophobicity ◽  
Tween 80 ◽  
Surface Hydrophobicity ◽  
Adherence Rate ◽  
Degrading Bacterium ◽  
Rpod Gene

The biodegradation of petroleum hydrocarbons has many potential applications and has attracted much attention recently. The hydrocarbon-degrading bacterium BL-27 was isolated from petroleum-polluted soil and was compounded with surfactants to improve biodegradation. Its 16S rDNA and rpoD gene sequences indicated that it was a strain of Bacillus subtilis. Strain BL-27 had extensive adaptability and degradability within a broad range of temperatures (25–50 °C), pH (4.0–10.0) and salinity (0–50 g/L NaCl). Under optimal conditions (45 °C, pH 7.0, 1% NaCl), the strain was able to degrade 65% of crude oil (0.3%, w/v) within 5 days using GC-MS analysis. Notably, strain BL-27 had weak cell surface hydrophobicity. The adherence rate of BL-27 to n-hexadecane was 29.6% with sucrose as carbon source and slightly increased to 33.5% with diesel oil (0.3%, w/v) as the sole carbon source, indicating that the cell surface of BL-27 is relatively hydrophilic. The strain was tolerant to SDS, Tween 80, surfactin, and rhamnolipids at a concentration of 500 mg/L. The cell surface hydrophobicity reduced more with the addition of surfactants, while the chemical dispersants, SDS (50–100 mg/L) and Tween 80 (200–500 mg/L), significantly increased the strain’s ability to biodegrade, reaching 75–80%. These results indicated that BL-27 has the potential to be used for the bioremediation of hydrocarbon pollutants and could have promising applications in the petrochemical industry.

scholarly journals Monolayer Adsorption of a “Bald” Mutant of the Highly Adhesive and Hydrophobic Bacterium Acinetobacter sp. Strain Tol 5 to a Hydrocarbon Surface

2008 ◽  
Vol 74 (8) ◽  
pp. 2511-2517 ◽  
Author(s):  
Katsutoshi Hori ◽  
Hisami Watanabe ◽  
Shun'ichi Ishii ◽  
Yasunori Tanji ◽  
Hajime Unno
Keyword(s):  
Cell Surface ◽  
Pure Water ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Green Technologies ◽  
Phase Partitioning ◽  
Degrading Bacterium ◽  
Monolayer Adsorption ◽  
Bacterium Strain ◽  
Math Test

ABSTRACT The affinity of microbial cells for hydrophobic interfaces is important because it directly affects the efficiency of various bioprocesses, including green biotechnologies. The toluene-degrading bacterium Acinetobacter sp. strain Tol 5 has filamentous appendages and a hydrophobic cell surface, shows high adhesiveness to solid surfaces, and self-agglutinates. A “bald” mutant of this bacterium, strain T1, lacks the filamentous appendages and has decreased adhesiveness but retains a hydrophobic cell surface. We investigated the interaction between T1 cells and an organic solvent dispersed in an aqueous matrix. During a microbial-adhesion-to-hydrocarbon (MATH) test, which is frequently used to measure cell surface hydrophobicity, T1 cells adhered to hexadecane droplet surfaces in a monolayer, whereas wild-type cells aggregated on the droplet surfaces. The adsorbed T1 cells on the hexadecane surfaces hindered the coalescence of the droplets formed by vortexing, stabilizing the emulsion phase. Following the replacement of the aqueous phase with fresh pure water after the MATH test, a proportion of the T1 cells that had adsorbed to the hydrocarbon surface detached during further vortexing, suggesting a reversible adsorption of T1 cells. The final ratio of the adhering cells to the total cells in the detachment test coincided with that in the MATH test. The adhesion of T1 cells to the hydrocarbon surface conformed to the Langmuir adsorption isotherm, which describes reversible monolayer adsorption. Reversible monolayer adsorption should be useful for green technologies employing two-liquid-phase partitioning systems and for bioremediation because it allows effective reaction and transport of hydrophobic substrates at oil-water interfaces.

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