A COMPARISON of the effects of two methods of acclimation on aerobic biodegradability

Abstract

The acclimation or adaptation of microorganisms to organic chemicals is an important factor influencing both the rate and the extent of biodegradation. In this study two acclimation procedures were evaluated in terms of their effectiveness in enhancing biodegradation, their relative ease of use in the laboratory, and the implications for biodegradability testing. In the single‐flask procedure, microorganisms were acclimated for 2 to 7 d in a single acclimation flask at constant or increasing concentrations of the test chemical without transfer of microorganisms. In the second procedure, the enrichment procedure, microorganisms were acclimated in a series of flasks over a 21‐d period by making adaptive transfers to increasing concentrations of the test chemical. Acclimated microorganisms from each procedure were used as the source of inoculum for subsequent biodegradation tests in which carbon dioxide evolution was measured. Six chemicals were tested: quinoline, p‐nitrophenol, N‐methylaniline, N,N‐dimethylaniline, acrylonitrile, and 2,2,4‐trimethyl‐1,3‐pentanediol monoisobutyrate. Microorganisms acclimated in the single‐flask procedure were much more effective than those acclimated in the enrichment procedure in degrading the test chemicals. The single‐flask procedure is more convenient to use, and it permits monitoring of the time needed for acclimation. The results from these studies have implications for the methodology used in biodegradation test systems and suggest caution before adopting a multiple‐flask, enrichment acclimation procedure before the performance of standardized tests for aerobic biodegradability.

Biotransformation of aromatic compounds from wastewaters containing N and/or S, by nitrification/denitrification: a review

“…In practice, the parameters strongly influencing the success of phenolic compounds degradation include the mode of cultivation (batch, feed-batch or continuous cultures), the presence or absence of other substrate than the contaminant tested, the type and size of the inoculum, the stabilization phase, the kind of electron acceptor (Buitrón and Capdeville 1995;Hu et al 1998;Razo-Flores et al 1996;Watson 1993;Zaidi et al 1996) and the stoichiometry of the system. Since the lipid membrane is the only barrier between the bacterial cytoplasm and the outside world, an alteration on the membrane structure can readily cause cell death, and the toxicity correlates well with the chemical properties of phenolic compounds as the cell membrane may be the main target of these antimicrobial agents (Heipieper et al 1991;Van Schie and Young 2000).…”

Environmental Assessment During Intelligence Preparation of the Battlefield (IPB) - Evaluation of the TIC-Master Computer Program

“…The hydrolysis of acrylonitrile is slow, with half-lives under acidic and basic conditions of 13 and 188 years, respectively (Ellington et al, 1987 AN Group, 1996;BASF AG, 1996). However, acrylonitrile will be extensively degraded (95-100%) following a short acclimation period if emitted to wastewater treatment plants (Tabak et al, 1980;Freeman & Schroy, 1984;Watson, 1993).…”

Widespread Microbial Adaptation to l-Glutamate-N,N-diacetate (L-GLDA) Following Its Market Introduction in a Consumer Cleaning Product

“…Adaptation has been seen in a variety of environmental compartments including fresh 2 and estuarine water, 3 periphyton, 4 sediment, 5−7 aquifers, 8 soil, 9,10 activated sludge, 11,12 and septic tank systems. 13 It has also been observed for a wide range of chemicals including toluene, 8 monosubstituted phenols, 14 nitrophenols, 1,8 aromatic amines, 12 polychlorinated biphenyls, 15 hydrocarbon mixtures, 9,16−18 cationic, [4][5][6][7]19 nonionic, 19 and anionic 13,19 surfactants, amino-carboxylic acid chelating agents, 2,3,11 herbicides, 20 and pesticides. 10 L-Glutamate-N,N-diacetate (L-GLDA), is an aminocarboxylate chelating agent and builder sold under the commercial name Dissolvine GL-47-S (Akzo Nobel, Amersfoort, The Netherlands).…”

“…Occurrence of microbial adaptation is usually demonstrated experimentally or inferred by comparing biodegradation in pre-exposed versus pristine sites. Adaptation has been seen in a variety of environmental compartments including fresh and estuarine water, periphyton, sediment, − aquifers, soil, , activated sludge, , and septic tank systems . It has also been observed for a wide range of chemicals including toluene, monosubstituted phenols, nitrophenols, , aromatic amines, polychlorinated biphenyls, hydrocarbon mixtures, ,− cationic, − , nonionic, and anionic , surfactants, aminocarboxylic acid chelating agents, ,, herbicides, and pesticides …”