Bacterial influence on partitioning rate during the biodegradation of styrene in a biphasic aqueous-organic system

Abstract

The degradation by a consortium of slightly-halophile marine bacteria of styrene initially dissolved in silicone oil was monitored in batch reactors stirred at 75, 125 and 500 rpm, respectively. In the 75 and 125 rpm cases, the styrene biodegradation rate was higher than the rate of spontaneous partitioning of styrene from the oil to the water, determined under abiotic conditions. Abiotic transfer tests carried out after biodegradation runs revealed that bacterial activity had resulted in a significant increase in the rate of styrene partitioning between the two liquid phases. Even though bacterial adsorption was noticeable at the oil-water interface, this effect appeared to be due to the release by the bacteria of chemicals in the aqueous phase. Similarity with observations made with Triton X-100 suggested that the chemicals released may have been biosurfactants or solubilizing agents.

Initial characterization of new bacteria degrading high-molecular weight polycyclic aromatic hydrocarbons isolated from a 2-year enrichment in a two-liquid-phase culture system

“…The formation of a biofilm at the interface of the aqueous and organic phases was observed in the present study and in other reports on TLP cultures (Efroymson and Alexander 1991; Ortega‐Calvo and Alexander 1994; Ascon‐Cabrera and Lebeault 1995; Jimenez and Bartha 1996; Osswald et al . 1996).…”

“…The formation of a biofilm at the interface of the aqueous and organic phases was observed in the present study and in other reports on TLP cultures (Efroymson and Alexander 1991;Ortega-Calvo and Alexander 1994;Ascon-Cabrera and Lebeault 1995;Jimenez and Bartha 1996;Osswald et al 1996). The microorganisms at the interface can presumably acquire the PAHs directly from the organic phase, and are probably more hydrophobic than the microorganisms freely dispersed in the aqueous phase.…”

Two-Liquid-Phase Slurry Bioreactors To Enhance the Degradation of High-Molecular-Weight Polycyclic Aromatic Hydrocarbons in Soil

“…Ascon‐Cabrera and Lebeault (31) used this compound to enhance the biodegradation of 1,2‐dichlorobenzene, 1,2,3‐ and 1,2,4‐trichlorobenzene, ethyl butyrate, and 2‐ethylbutyraldehyde by a mixed culture, and ethyl butyrate and 2,4,6‐trichlorophenol by defined cultures (32, 33). Better degradation of styrene (37, 38) and several PAHs (34) was also achieved by mixed cultures in TLP bioreactors in which silicone oil was used as the water‐immiscible liquid. This is the first report however in which a TLP system was combined with a slurry system to improve the biodegradation of target compounds into soil.…”

PAHs biodegradation potential of indigenous consortia from agricultural soil and contaminated soil in two-liquid-phase bioreactor (TLPB)

“…Additionally, the organic phase usually exhibits a higher affinity for oxygen than pure water, thus larger amounts of oxygen can be transferred to TLPB, which facilitates the aerobic treatment of pollutants [15]. So far the TLPB has been widely employed in biodegradation of organic compounds such as styrene [16,17], chlorobenzenes [18] and PAHs [19][20][21], and silicone oil is most frequently selected as the organic phase [14,22,23]. Such applications achieved high efficiency in eliminating hydrophobic compounds when suitable microorganisms were introduced [22,[24][25][26].…”