High expression of ring-hydroxylating dioxygenase genes ensure efficient degradation of p-toluate, phthalate, and terephthalate by Comamonas testosteroni strain 3a2.

Para-toluic acid, a major pollutant in industrial wastewater, is hazardous to human health. It has been demonstrated that Gram-negative bacteria are among the most effective degraders of para-toluic acid. In this study, the ability of Comamonas testosteroni strain 3a2, isolated from a petrochemical industry wastewater, to degrade para-toluic acid was investigated. The effect of different carbon (glucose and ethylene glycol) and nitrogen sources (urea, yeast extract, peptone, NaNO3, NH4NO3) on the biodegradation of para-toluic acid by the isolate 3a2 was evaluated. Furthermore, ring hydroxylating dioxygenase genes were amplified by PCR and their expression was evaluated during the biodegradation of para-toluic acid. The results indicated that strain 3a2 was able to degrade up to 1000 mg/L of para-toluic acid after 14 h. The highest degradation yield was recorded in the presence of yeast extract as nitrogen source. However, the formation of terephthalic acid and phthalic acid was noted during para-toluic acid degradation by the isolate 3a2. Toluate 1,2-dioxygenase, terephthalate 1,2 dioxygenase, and phthalate 4,5 dioxygenase genes were detected in the genomic DNA of 3a2. The induction of ring hydroxylating dioxygenase genes was proportional to the concentration of each hydrocarbon. This study showed that the isolate 3a2 can produce terephthalate and phthalate during the para-toluic acid biodegradation, which were also degraded after 24 h.

Biodegradation of Terephthalic Acid by Isolated Active Sludge Microorganisms and Monitoring of Bacteria in a Continuous Stirred Tank Reactor

Abstract Terephthalic acid is extensively used as an important raw material in polyester fibers, as well as the production of polyethylene terephthalate bottles and textile industries. Especially, in the petrochemical industry, toxic chemicals are released to the atmosphere during the production of polyethylene terephthalate, unless the wastewater treatment is carried out. It's a well-known fact that chemicals have serious side effects on human health, so manufacturing companies should not dispose of such harmful chemicals without treatment. Biodegradation is an effective option for eco-friendly degradation of hydrocarbons. Hydrocarbon-degrading bacteria are everywhere in environment and can utilize these chemicals as sources of carbon and energy. In the present study, aerobic bacterial strains T1, T4, T5, and TK were isolated from activated sludge and crude oil deposits of a petrochemical company in Turkey. The strains were identified to be Pseudomonas sp., Chryseobacterium sp., Burkholderia sp., and Arthrobacter sp. according to morphological, physiological and biochemical characteristics. The strains were able to degrade about 100% of 100 mg/L terephthalic acid within, respectively, 8, 67, 52, 24 hour as sole carbon and energy source. Therefore, these isolates can be effectively used for degradation of terephthalic acid contaminated sites. In addition to this, a Continuous Stirred Tank Reactor (CSTR) was used to test the biodegradation capabilities of the isolates in the activated sludge system. Throughout the biodegradation, bacterial existence and numbers were monitored using designed primer-probe sets in real-time polymerase chain reaction (PCR).

Delivery of pemetrexed by magnetic nanoparticles: design, characterization, in vitro and in vivo assessment.

Drug-loaded magnetic nanoparticles have been developed because of the advantages of specific drug targeting in cancer treatment. Pemetrexed (PEM) is a multi-targeting antifolate agent that is effective for the treatment of many cancers, for example, non-small cell lung cancer. Here, PEM loaded magnetic O-carboxymethyl chitosan (O-CMC) nanoparticles were prepared to deliver PEM on tumor tissue with an external magnetic field. The modification of chitosan to O-CMC was confirmed by FTIR analysis. Nanoparticle synthesis was performed via ionic gelation method. The diameter of magnetic O-CMC nanoparticles (MCMC) was found to be 130.1 ± 22.96 nm. After PEM loading, diameter was found to be 123.9 ± 11.42 nm. The drug release of PEM loaded MCMC (PMCMC) was slower in physiological medium than in acidic medium. A549-luc-C8 and CRL5807 cell lines were used for MTT test which showed that IC50 values of nanoparticles were lower than PEM. The antitumor efficiency of PMCMC in xenograft tumor model was examined with in vivo imaging system (IVIS) and caliper and with hematological analyses. In vivo studies revealed that PMCMC had targeted antitumor activity in A549-luc-C8-tumor-bearing mice compared to PEM. As a result, it was suggested that PMCMC have great potential for the treatment of non-small cell lung cancer.