Metabolism of benzene, toluene, and xylene hydrocarbons in soil
نویسندگان
چکیده
Enrichment cultures obtained from soil exposed to benzene, toluene, and xylene (BTX) mineralized benzene and toluene but cometabolized only xylene isomers, forming polymeric residues. This observation prompted us to investigate the metabolism of 14C-labeled BTX hydrocarbons in soil, either individually or as mixtures. BTX-supplemented soil was incubated aerobically for up to 4 weeks in a sealed system that automatically replenished any O2 consumed. The decrease in solvent vapors and the production of 14CO2 were monitored. At the conclusion of each experiment, 14C distribution in solvent-extractable polymers, biomass, and humic material was determined, obtaining 14C mass balances of 85 to 98%. BTX compounds were extensively mineralized in soil, regardless of whether they were presented singly or in combinations. No evidence was obtained for the formation of solvent-extractable polymers from xylenes in soil, but 14C distribution in biomass (5 to 10%) and humus (12 to 32%) was unusual for all BTX compounds and especially for toluene and the xylenes. The results suggest that catechol intermediates of BTX degradation are preferentially polymerized into the soil humus and that the methyl substituents of the catechols derived from toluene and especially from xylenes enhance this incorporation. In contrast to inhibitory residues formed from xylene cometabolism in culture, the humus-incorporated xylene residues showed no significant toxicity in the Microtox assay.
منابع مشابه
In-Situ Treatment of Soil Contaminated by Benzene (A BTEX Compound)
Introduction Gasoline is a complex solution of different hydrocarbons. Naturally occurring petroleum contains aromatic hydrocarbons, a class of unsaturated hydrocarbons that includes benzene, toluene, ethylenzene, and xylene (collectively known as BTEX). Since the EPA banned lead additions to gas in 1973, aromatic hydrocarbons were added to increase the octane concentration, thereby maximizing ...
متن کاملSubstrate interactions during the biodegradation of benzene, toluene, ethylbenzene, and xylene (BTEX) hydrocarbons by the fungus Cladophialophora sp. strain T1.
The soil fungus Cladophialophora sp. strain T1 (= ATCC MYA-2335) was capable of growth on a model water-soluble fraction of gasoline that contained all six BTEX components (benzene, toluene, ethylbenzene, and the xylene isomers). Benzene was not metabolized, but the alkylated benzenes (toluene, ethylbenzene, and xylenes) were degraded by a combination of assimilation and cometabolism. Toluene a...
متن کاملModulation of affinity of a marine pseudomonad for toluene and benzene by hydrocarbon exposure.
Trace (microgram liter) quantities of either toluene or benzene injected into an amino-acid-limited continuous culture of Pseudomonas sp. strain T2 were utilized immediately with affinities of 2.6 and 6.8 liters g of cells h, respectively, and yielded large amounts of organic products, carbon dioxide, and cells. The immediate utilization of hydrocarbons by hydrocarbon-deprived organisms helps t...
متن کاملModulation of Affinity of a Marine Pseudomonad for Toluene and Benzene by Hydrocarbon Exposure
Trace (microgram liter-') quantities of either toluene or benzene injected into an amino-acid-limited continuous culture of Pseudomonas sp. strain T2 were utilized immediately with affinities of 2.6 and 6.8 liters g of cells-' h-1, respectively, and yielded large amounts of organic products, carbon dioxide, and cells. The immediate utilization of hydrocarbons by hydrocarbon-deprived organisms h...
متن کاملپاکسازی بیولوژیکی خاکهای آلوده به اتیل بنزن, تولوئن و نفتالین
Background & Objective: Aromatic hydrocarbons are produced by incomplete combustion of fossil fuels and pollute the soil following the emission into the atmosphere by precipitation. Numerous studies suggest that microbial inoculation has contributed to biodegradation of aromatic hydrocarbons. However, other studies have not confirmed the efficacy of this procedure in biodegradation. Regarding t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Applied and environmental microbiology
دوره 64 12 شماره
صفحات -
تاریخ انتشار 1998