The Role of Dissolved Silica on the Biodegradation of Octylamine

• Published in: Environmental science & technology 1999-11, Vol.33 (21), p.3723-3729
• Main Authors: Selig, Hildegarde, Hayes, Kim F, Adriaens, Peter
• Format: Article
• Language: English
• Subjects: Applied sciences; Biodegradable materials; Biodegradation; Biological and physicochemical properties of pollutants. Interaction in the soil; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Groundwater; Groundwaters; Natural water pollution; octylamine; Organic chemistry; Pollution; Pollution, environment geology; Rhodococcus erythropolis; silica; Soil and sediments pollution; Studies; Toxicity; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es9808595

Dissolution of aquifer-associated mineral solids such as silica may affect the natural bioattenuation of organic compounds by altering their chemical speciation and thus their biodegradability. A study was conducted to evaluate the effect of dissolved silica on the rates of biodegradation of a cationic surfactant, octylamine, by Rhodococcus erythropolis. The presence of dissolved silica or a surrogate added by dissolving sodium metasilicate significantly enhanced the biodegradation rates of octylamine. Microbial kinetic studies based on the Monod/Haldane equation indicated that the rate enhancement was caused by a decrease in the inhibitory properties of octylamine, rather than by an improvement in buffering of the medium. In the presence of dissolved silica, μmax and K s remain virtually unaffected, but the inhibition constant, K i, increased several orders of magnitude (from K i = 1.32 mM in the silica-free system to K i > 106 mM in the silica system). Surface tension studies suggested that the presence of dissolved silica significantly decreased the surface-activity of octylamine.