Bioremediation of BTEX Hydrocarbons: Effect of Soil Inoculation with the Toluene-Growing Fungus Cladophialophora Sp. Strain T1

Abstract

The biodegradation of a mixture of benzene, toluene, ethylbenzene, xylene, (BTEX) and methyl-tert-butyl ether (MTBE) was studied in soil microcosms. Soil inoculation with the toluene-metabolising fungus Cladophialophora sp. strain T1 was evaluated in sterile and non-sterile soil. Induction of biodegradation capacity following BTEX addition was faster in the soil native microflora than in axenic soil cultures of the fungus. Toluene, ethylbenzenes, and the xylenes were metabolized by the fungus but biodegradation of benzene required the activity of the indigenous soil microorganisms. MTBE was not biodegraded under the tested environmental conditions. Biodegradation profiles were also examined under two pH conditions after a long term exposure to BTEX. At neutral conditions the presence of the fungus had little effect on the intrinsic soil biodegradation capacity. At an acidic pH, however, the activity of the indigenous degraders was inhibited and the presence of Cladophialophora sp. increased significantly the biodegradation rates of toluene and ethylbenzene. Comparison of the BTEX biodegradation rates measured in soil batches combining presence and absence of indigenous degraders and the fungal inoculum indicated that no severe antagonism occurred between the indigenous bacteria and Cladophialophora sp. The presence of the fungal inoculum at the end of the experiments was confirmed by PCR-TGGE analysis of small subunits of 18S rDNA.

Biodegradation activity in the soil contaminated with oil products

“…To overcome this problem surfactants have been added to contaminated soils to improve the availability of hydrocarbons. The rate of degradation depends on the microbial population, the type and level of contamination (Boldu-Prenafeta et al, 2004). Another way of increasing the biodegradation efficiency can be improving the aeration; the addition of biogenic elements (phosphorus, nitrogen, potassium) has also been proposed (Liužinas, Jankevičius, 2003;Si-Zhong et al, 2009).…”

“…Therefore, the aim of this work was to determine how sewage sludge can influence the biodegradation activity of soil contaminated with oil products, as well as to determine what groups of microorganisms influence these processes most. It is known that the efficiency of this process depends on the number of microorganisms present in the soil and their ability to adapt, specificity of their functioning, nutritional substances suitable for growth, composition of pollutants, and physicochemical properties of soil (Iwamoto, Nasu, 2001;Vasudevan, Rajaram, 2001;Boldu-Prenafeta et al, 2004). It was determined earlier that a small amount of metals in the sewage sludge only speeds up the treatment.…”

Bioremediation of Toluene using Microbial Consortium Obtained from Industrial Effluent

“…Environmental Contamination due to rise in Petrochemical Industry has become a matter of serious concern from the last few decades (Prenafeta-Bold´u1, 2004). Waste effluent generated from the petrochemical Industry consists of highly toxic derivatives of organic compounds like benzene, toluene, xylene and other poly aromatic compounds .…”

Review: <i>BTEX compounds in water – future trends and directions for water treatment</i>

“…The group of microorganisms mostly reported for use as bioremediation agents are bacteria; however, fungal species have also been reported to be able to degrade BTEX compounds for use as carbon and energy sources. Prenafeta-Boldú et al (2004) reported the use of a toluene-metabolising fungus to degrade BTEX compounds under various pH conditions. Alvarez and Vogel (1995) highlighted the ability of indigenous bacteria to degrade BTEX compounds without suffering as much metabolic inhibition as micro-organisms from other sources.…”