Bacterial adhesion to glass and metal-oxide surfaces.

The effect of fluid velocity on the transport of motile and nonmotile bacteria was studied in saturated soil columns using radiolabeled cells. According to colloid filtration theory, decreasing the...

Influence of Fluid Velocity and Cell Concentration on the Transport of Motile and Nonmotile Bacteria in Porous Media

: The biodegradation of naphthalene, creosote, and naphthalene-enriched creosote applied to wood pilings used at Roosevelt Roads Naval Base in Puerto Rico was studied. It was found that naphthalene-degrading bacteria rapidly colonized new wood pilings within hours after installation but that the rate of attachment and subsequent colonization was significantly slower for the naphthalene- enriched creosote-treated wood. The bacteria attaching to new wood were predominantly stalked bacteria whereas the microbial flora of old wood reflected that of the surrounding water and sediment. The gut of Limnoria tripunctata reared in the laboratory was found to be free of bacteria but the external surfaces of the borer were heavily colonized by bacteria. (Author)

Microbial Degradation of Petroleum in the Marine Environment.

A pentachlorophenol (PCP)-mineralizing bacterium was isolated from polluted soil and identified as Pseudomonas sp. strain RA2. In batch cultures, Pseudomonas sp. strain RA2 used PCP as its sole source of carbon and energy and was capable of completely degrading this compound as indicated by radiotracer studies, stoichiometric release of chloride, and biomass formation. Pseudomonas sp. strain RA2 was able to mineralize a higher concentration of PCP (160 mg liter-1) than any previously reported PCP-degrading pseudomonad. At a PCP concentration of 200 mg liter-1, cell growth was completely inhibited and PCP was not degraded, although an active population of Pseudomonas sp. RA2 was still present in these cultures after 2 weeks. The inhibitory effect of PCP was partially attributable to its effect on the growth rate of Pseudomonas sp. strain RA2. The highest specific growth rate (mu = 0.09 h-1) was reached at a PCP concentration of 40 mg liter-1 but decreased at higher or lower PCP concentrations, with the lowest mu (0.05 h-1) occurring at 150 mg liter-1. Despite this reduction in growth rate, total biomass production was proportional to PCP concentration at all PCP concentrations degraded by Pseudomonas sp. RA2. In contrast, final cell density was reduced to below expected values at PCP concentrations greater than 100 mg liter-1. These results indicate that, in addition to its effect as an uncoupler of oxidative phosphorylation, PCP may also inhibit cell division in Pseudomonas sp. strain RA2.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of a novel Pseudomonas sp. that mineralizes high concentrations of pentachlorophenol.

Seven chemicals, three buffers, and a salt solution known to affect bacterial attachment were tested to quantify their abilities to enhance the penetration of Alcaligenes paradoxus in porous media. Chemical treatments included Tween 20 (a nonionic surfactant that affects hydrophobic interactions), sodium dodecyl sulfate (an anionic surfactant), EDTA (a cell membrane permeabilizer that removes outer membrane lipopolysaccharides), sodium PPi (a surface charge modifier), sodium periodate (an oxidizer that cleaves surface polysaccharides), lysozyme (an enzyme that cleaves cell wall components), and proteinase K (a nonspecific protease that cleaves peptide bonds). Buffers included MOPS [3-(N-morpholino)propanesulfonic acid], Tris, phosphate, and an unbuffered solution containing only NaCl. Transport characteristics in the porous media were compared by using a sticking coefficient, alpha, defined as the rate at which particles stick to a grain of medium divided by the rate at which they strike the grain. Tween 20 reduced alpha by 2.5 orders of magnitude, to alpha = 0.0016, and was the most effective chemical treatment for decreasing bacterial attachment to glass beads in buffered solutions. Similar reductions in alpha were achieved in unbuffered solutions by reducing the solution ionic strength to 0.01 mM. EDTA, protease, and other treatments designed to alter cell structures did not reduce alpha by more than an order of magnitude. The number of bacteria retained by the porous media was decreased by treatments that made A. paradoxus more hydrophobic and less electrostatically charged, although alpha was poorly correlated with electrophoretic mobility and hydrophobicity index measurements at lower alpha values.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of different chemical treatments on transport of Alcaligenes paradoxus in porous media.

Microbial transport through porous media: The effects of hydraulic conductivity and injection velocity☆

http://envismadrasuniv.org/Bioremediation/pdf/Decision%20making%20%20Is%20bioremediation.pdf

K.L. Duston

Papers

Microbial transport through porous media: The effects of hydraulic conductivity and injection velocity☆

Decision making — is bioremediation a viable option?