Cyclodextrin-enhanced degradation of toluene and p-toluic acid by Pseudomonas putida

Abstract

Degradation of an immiscible aromatic solvent, toluene, and a water-soluble aromatic compound, p-toluic acid, by a Pseudomonas putida strain in the presence of ␤-cyclodextrin (␤-CD) was investigated. The ability of CDs to interact with hydrophobic organics and form inclusion compounds was exploited in this study to remove or alleviate the toxicities of substrates and consequently to enable or enhance degradation. Liquid toluene was found to be highly toxic to P. putida. However, this phase toxicity was removed when crystalline ␤-CDcomplexed toluene was provided as the substrate. The latter was fully degraded at a concentration of up to 10 g/liter. Degradation of toluene vapors was enhanced in the presence of ␤-CD as a result of reduced molecular toxicity and facilitated absorption of the gaseous substrate. Similarly, ␤-CD alleviated the inhibitory effect of p-toluic acid on P. putida. This protective effect of CD was remarkably more prominent when the microbial culture was shock loaded with an otherwise toxic dose of p-toluic acid (1.8 g/liter).

Electrospun nylon 6,6 nanofibers functionalized with cyclodextrins for removal of toluene vapor

“…Here, toluene vapor is selected as a model VOC since CD can form IC with toluene that is commonly used in industry for certain purposes . The toluene vapor entrapment performance of the nylon 6,6 and nylon 6,6/CD nanofibers was compared.…”

Methyl‐β‐cyclodextrin‐enhanced solubilization and aerobic biodegradation of polychlorinated biphenyls in two aged‐contaminated soils

“…According to previous findings (Christodoulatos and Koutsospyros, 1998;Cookson, 1995;Fava et al, , 2000Fava and Ciccotosto, 2002), this finding may be ascribed to the high degree of homogeneity and mass transfer rates probably achieved in the soil matrix treated in the recycled reactors where, therefore, improved interactions between RAMEB and the adsorbed pollutants were probably reached. The occurrence of effective interactions between RAMEB and adsorbed PCBs may have great relevance for PCB solubilization and bioavailability in such reactors, as CDs typically enhance the bioavailability of water-insoluble or adsorbed hydrophobic molecules by interacting with them; the water-soluble (or water-insoluble) inclusion complexes resulting from this interaction can then liberate the target molecules in the water phase, making them more available to biological receptors (Bardi et al, 2000;Schwartz and Bar, 1995;Sheremata and Hawari, 2000;Szente and Szejtli, 1999;Wang et al, 1998).…”

“…In the microbiological conversion of poorly soluble substrates, such as steroids and lipids, cyclodextrins (CDs) are used at the industrial scale to improve the bioavailability of these substrates, resulting in accelerated and more complete conversion (Szejtli, 1990). During the last decade, a series of investigations have reported on the interaction between CDs and hydrophobic organic pollutants aiming successfully at the enhancement of their bioavailability and biodegradation in different matrixes, such as liquid cultures of specialized bacteria (Bardi et al, 2000;Fava and Grassi, 1996;Schwartz and Bar, 1995) along with contaminated soils (Gruiz et al, 1996;Sheremata and Hawari, 2000;Wang et al, 1998), wastewaters (Olah et al, 1988), and aquifers (Boving et al, 1999;McCray et al, 1998). Two CDs (i.e., hydroxypropyl-␤-CD and ␥-CD) have been proven to be nontoxic and biodegradable additives capable of enhancing the bioavailability and aerobic biodegradation of PCBs in an aged-contaminated soil treated under both slurry-and fixed-phase aerobic conditions .…”

Longitudinal changes in microbial assemblages of the Ogeechee River

“…probably favour growth of P. putida because of the ability of these bacteria to use aromatic compounds, such as toluene (e.g. Schwartz & Bar, 1995). Acinetobacter calcoaceticus abundance showed little variability among sites.…”