Biodegradation of Polyethoxylated Nonylphenols

Abstract

Polyethoxylated nonylphenols, with different ethoxylation degrees (NPEOx), are incorporated into many commercial and industrial products such as detergents, domestic disinfectants, emulsifiers, cosmetics, and pesticides. However, the toxic effects exerted by their degradation products, which are persistent in natural environments, have been demonstrated in several animal and invertebrate aquatic species. Therefore, it seems appropriate to look for indigenous bacteria capable of degrading native NPEOx and its derivatives. In this paper, the isolation of five bacterial strains, capable of using NPEO15, as unique carbon source, is described. The most efficient NPEO15 degrader bacterial strains were identified as Pseudomonas fluorescens (strain Yas2) and Klebsiella pneumoniae (strain Yas1). Maximal growth rates were reached at pH 8, 27°C in a 5% NPEO15 medium. The NPEO15 degradation extension, followed by viscometry assays, reached 65% after 54.5 h and 134 h incubation times, while the COD values decreased by 95% and 85% after 24 h for the Yas1 and Yas2 systems, respectively. The BOD was reduced by 99% and 99.9% levels in 24 h and 48 h incubations. The viscosity data indicated that the NPEO15 biodegradation by Yas2 follows first-order kinetics. Kinetic rate constant (k) and half life time (τ) for this biotransformation were estimated to be 0.0072 h−1 and 96.3 h, respectively.

Bio-Removal of Methylene Blue from Aqueous Solution by Galactomyces geotrichum KL20A

“…Figure 3b shows the results after utilizing the kinetic model (Equation (4)). The value obtained for the kinetic constant of the MB removal process by G. geotrichum KL20A at 35 • C was 2.2 × 10 −2 h −1 corresponding to a half time for biotransformation of 31.2 h. This value of the kinetic constant is considerably higher than that obtained for other species for the degradation of pollutants: (a) the degradation of polyethoxylates by bacteria, which reported a k t value of 7.2 × 10 −3 h −1 a half time for biotransformation of 96 h [44]; (b) the removal of disperse blue with Klebsiella sp., yields a k t value of 1.0 × 10 −3 h −1 for a reaction time of 160 h [45].…”

Plant age and genotype affect the bacterial community composition in the tuber rhizosphere of field-grown sweet potato plants

“…In addition, in comparison with bulk soil, significantly higher numbers of bacterial genera were enriched in the tuber rhizosphere of IPB‐137, such as Pseudomonas, Sphingobium , Acinetobacter , Chryseobacterium , Chitinophaga , and Sphingobacterium . Isolates belonging to some of the genera enriched in the tuber rhizosphere of IPB‐137, such as Pseudomonas and Sphingobium, were previously reported to be involved in the degradation of aromatic ring structures (Önneby et al ., ; Ruiz et al ., ; Tien et al ., ). It can only be speculated that aromatic compounds might have been released from the tuberous roots eventually as a result of increased insect attacks.…”

Spatio-temporal variations in chemical pollutants found among urban deposits match changes in thiopurine S-methyltransferase-harboring bacteria tracked by the tpm metabarcoding approach

“…These results suggested that the bacterial community of the pit and its tpmharboring taxa can contribute at the degradation of NPEs. Further analyses will be required to demonstrate a role of the tpm or associated genes in this degradation process but a tpm-harboring strain of P. fluorescens was found as one of the best degrader of NPEs (Ruiz et al, 2013). It is to be noted that the Predicted No Effect Concentration (PNEC) for NPs in sediments (according to the European Union risk assessment report) was estimated at 39 ng/g.…”