Chlortetracycline Antibiotics Research Articles

Performance of four different microalgae-based technologies in antibiotics removal under multiple concentrations of antibiotics and strigolactone analogue GR24 administration

The formation of symbionts by using different combinations of endophytic bacteria, microalgae, and fungi to purify antibiotics-containing wastewater is an effective and promising biomaterial technology. As it enhances the mixed antibiotics removal performance of the bio-system, this technology is currently extensively studied. Using exogenous supplementation of various low concentrations of the phytohormone strigolactone analogue GR24, the removal of various antibiotics from simulated wastewater was examined. The performances of Chlorella vulgaris monoculture, activated sludge–C. vulgaris–Clonostachys rosea, Bacillus licheniformis–C. vulgaris–C. rosea, and endophytic bacteria (S395-2)–C. vulgaris–C. rosea co-culture systems were systematically compared. Their removal capacities for tetracycline, oxytetracycline, and chlortetracycline antibiotics from simulated wastewater were assessed. Chlorella vulgaris–endophytic bacteria–C. rosea co-cultures achieved the best performance under 0.25 mg L−1 antibiotics, which could be further enhanced by GR24 supplementation. This result demonstrates that the combination of endophytic bacteria with microalgae and fungi is superior to activated sludge–B. licheniformis–microalgae–fungi systems. Exogenous supplementation of GR24 is an effective strategy to improve the performance of antibiotics removal from wastewater.

Long-term inhibition of chlortetracycline antibiotics on anaerobic digestion of swine manure

This study aimed to identify whether chronic effects are present in the anaerobic digestion (AD) of swine manure (SM) containing chlortetracycline (CTC), which is one of the major broad-spectrum veterinary antibiotics, and to elucidate the long-term inhibitory effects and recovery from the inhibition based on AD performance and microbial community. Two continuous-stirred tank reactors treating SM with and without CTC spiking (3 mg/L) were operated for 900 days. Due to the degradation and transformation, the total concentration including CTC's epimer and isomer in the test reactor was 1.5 mg/L. The exposure level was determined according to probabilistically estimated concentrations with uncertainties in field conditions. Until the cessation of CTC exposure on day 585, the methane generation of test reactor continuously decreased to 55 ± 17 mL/g-VS/day, 53% that of control. The methane generation and organic removal were not recovered within 300 days after the CTC exposure was stopped. During the experiment, stability parameters such as pH, total ammonium nitrogen, the composition of methane and alkalinity were the same for both reactors. The concentration and composition of VFAs in the test reactor were different with those of control but not in inhibition level. Microbial profiles revealed that reduction in bacterial diversity and changed balance in microbial species resulted in the performance downgrade under the long-term antibiotic pressure. Since it is hard to recover from the inhibition and difficult to predict the inhibition using physicochemical indicators, continuous exposure to CTC needs to be avoided for the sustainable management of AD plants treating SM.

Rational design of in‐situ‐modified resorcinol formaldehyde aerogels for removing chlortetracycline antibiotics from aqueous solutions

AbstractOrganic resorcinol formaldehyde aerogels with distinct pore sizes/surface areas in different ratios of (resorcinol/catalyst) R/C = 300, 400, 600 and (resorcinol/water) R/W = 2 were prepared utilizing sol–gel technique and in‐situ modified by incorporating 1 wt% meta‐phenylenediamine. The porous nanostructure, surface area, and pore size of the aerogels were characterized by scanning electron microscopy, Brunauer–Emmett–Teller, and Barrett–Joyner–Halenda techniques. Raman spectroscopy, Fourier transform infrared spectroscopy, and X‐ray diffraction were employed to get understanding into the chemical structure. Furthermore, we investigated the removal percentage of antibiotic via UV–vis spectroscopy. The ability of modified aerogels in removing chlortetracycline (CTC) at different pH values (2–12), contact times (2–24 h), initial concentrations of CTC (50–100 mg L−1), and the adsorbent dose (2–10 mg) was evaluated. Consequently, the adsorption optimum conditions were found, the adsorption isotherms were measured, and isotherm models were fitted to the results to interpret the kinetics of adsorption. The obtained fitting parameters using the pseudo‐second‐order model revealed a well alignment with the experimental data. Finally, we demonstrated that the modified‐aerogels have a high capacity in CTC antibiotics removal up to 90% and an adsorption capacity of 440 mg g−1 as well as an efficient regeneration capacity for five consecutive cycles without significant degradation of the adsorption properties.

Screening of oxytetracycline & chlortetracycline residues in poultry feeds in Bangladesh

A total of 112 poultry feed samples were screened for oxytetracycline and chlortetracycline antibiotic residues by thin-layer chromatography (TLC). The samples were collected from Natore, Naogaon, Rangpur and Comilla districts of Bangladesh. Poultry feed samples were classified according to their product type (homemade, commercial) and types of poultry feed (broiler feed, layer feed and sonali feed). All the homemade poultry feed samples (100%) tested positive for oxytetracycline and chlortetracycline antibiotic residue when screened. About 95% of commercial poultry feed tested positive for antibiotic residue in all four districts. In this study, the positive screening for oxytetracycline and chlortetracycline antibiotic residue in broiler, layer and sonali poultry feed types are 98%, 95% and 90%, respectively. This study also observed that antibiotic residue remained in feed samples irrespective of temperature and time as they had been stored for about a year at room temperature. From this study, it was revealed that the use of antibiotics in poultry feeds was extensive. Moreover, the duration of sustaining in poultry feed also raised concerns regarding their use and effect on the environment. This study has also increased the concern about the strict monitoring of the use of antibiotics in the poultry industry.

Long-Term Inhibition of Chlortetracycline Antibiotics on Anaerobic Digestion of Swine Manure

Long-Term Inhibition of Chlortetracycline Antibiotics on Anaerobic Digestion of Swine Manure

Epimerization and Isomerization Kinetics of Chlortetracycline Antibiotics in Swine Manure and its Anaerobic Digestate

Epimerization and Isomerization Kinetics of Chlortetracycline Antibiotics in Swine Manure and its Anaerobic Digestate

Long-Term Inhibition of Chlortetracycline Antibiotics on Anaerobic Digestion of Swine Manure

Long-Term Inhibition of Chlortetracycline Antibiotics on Anaerobic Digestion of Swine Manure

Synthesis and characterization of γ-cyclodextrin-graphene oxide nanocomposite: Sorption, kinetics, thermodynamics and simulation studies of tetracycline and chlortetracycline antibiotics removal in water

γ-Cyclodextrin-graphene oxide nanocomposite was synthesized and characterized for sorption, kinetics, thermodynamics, and simulation studies of tetracycline and chlortetracycline antibiotics removal from water. The optimized sorption parameters were 400 mg/L concentration, 30 min contact time, pH 8.0, dose 1.0 g/L and 25 °C temperature. The sorption followed Langmuir, Temkin, and D-Rs models. The maximum removals of tetracycline and chlortetracycline were 91.25 and 93.75% respectively, with a variation of percentage removal at different pHs ranges [355.0 (88.75%), 360.0 (90.0%) and 365.0 mg/g (91.25%) for tetracycline and 365.0 (91.25%), 370.0 (92.5%) and 375.0 mg/g (93.75%) chlortetracycline]. The sorption followed pseudo-second kinetic order reaction and liquid film diffusion kinetic model. The positive values of entropy (12.043 & 12.842 kJ/mol.K) and negative values of enthalpy (-0.944 & −1.113 kJ/mol) and free energy (-14.60 to −13.55 kJ/mol) confirmed the spontaneous sorption at all temperatures. The simulation results agreed with the sorption results. Also, the modeling was used to ascertain the supramolecular mechanism, which involved hydrogen bonding and π-π interactions.

Synthesis and characterization of modified resorcinol formaldehyde aerogel as a novel absorbent to remove oxytetracycline and chlortetracycline antibiotics from wastewater

Synthesis and characterization of modified resorcinol formaldehyde aerogel as a novel absorbent to remove oxytetracycline and chlortetracycline antibiotics from wastewater

Uncertainty-based concentration estimation of chlortetracycline antibiotics in swine farms and risk probability assessment for agricultural application of manure

Consideration of livestock farming practices is necessary for the reliable prediction of veterinary antibiotics concentrations in livestock manure and soil and characterization of their ecological risks. This study aims to predict concentrations of chlortetracycline (CTC) generated from slurry pit and evaluate its ecological risk in soil based on the European Medicine Agency guidelines by considering slurry pit farm practices such as cleaning water volume and those uncertainties. Additionally, sensitivity analysis was conducted on the exposure estimation of CTC in soil employing the Monte Carlo simulation. The predicted environmental concentrations of CTC in the slurry pit and soil were in a range of 0.54–5.64 mg/kgmanure and 3.42–67.59 μg/kgsoil, respectively, for a 90 % confidence level. The predicted ranges included the measured values reported in previous studies. The probability of risk quotient (RQ) exceeding one was estimated at 9.3 % based on the Monte Carlo simulation. The four most influential factors on the exposure to CTC in soil were identified as nitrogen in fertilizer/compost, cleaning water volume, ratio of sick pigs requiring antibiotics, and pit emptying cycles. The results indicate that the ecological risk of CTC in the soil is possible and can be controlled by slurry pit farm practices.

Fate of chlortetracycline antibiotics during anaerobic degradation of cattle manure

As veterinary antibiotics (VAs) cause adverse effects on nature, anaerobic digestion (AD) of livestock manure has been receiving attention as an exposure route of VAs. This research evaluated the anaerobic degradation and phase distribution of chlortetracycline (CTC) with its epimer (4-epi-CTC, ECTC) and isomer (Iso-CTC, ICTC). In addition, whether CTC can inhibit not only AD of a substrate but also the degradation of CTC was assessed. Anaerobic batch assays were performed with cattle manure for 30 days by varying the initial concentration of CTC; 0, 10, 25, 50, and 100 mg/L. Approximately 25–43 % (w/w) of CTC was primarily degraded while 18–25 % and 20–26 % of CTC was transformed into ECTC and ICTC, respectively. Up to 88 % (w/w) of the remaining CTC, ECTC, and ICTC was present in the solid phase. In addition, CTC inhibited not only the mineralization of the cattle manure but also the degradation of CTC due to co-metabolism. In conclusion, significant quantities of CTC, ECTC, and ICTC can be exposed to nature by solid phase of anaerobic digestate. The inhibition on AD can reduce the degradation of CTC, ECTC, and ICTC during the AD.

Comparing adsorption properties of NH 4 Cl-modified activated carbon towards chlortetracycline antibiotic with those of commercial activated carbon

Abstract In this work, kinetics, equilibrium, thermodynamic and other adsorption properties of a novel activated carbon with regular-shaped pores (NH4Cl-modified activated carbon, NAC) for removal of chlortetracycline antibiotic from aqueous solutions was compared with those of a commercial standard activated carbon (SAC). Effects of temperature, on chlortetracycline adsorption by both adsorbents were carefully investigated and compared. Then optimum conditions were used for comparing the adsorption properties of adsorbents. Among the isotherm models studied, the equilibrium experimental data of both activated carbons were followed by Redlich-Peterson model, and the parameters calculated from the studied models showed more favourability of chlortetracycline adsorption onto NAC via the physical π-π electron-donor-acceptor interaction. The experimental data were fitted to several kinetic models and, based on calculated respective parameters such as rate constants, equilibrium adsorption capacities, correlation coefficients and statistical indices, both the Ritchie second order and pseudo second-order model showed the best in describing the adsorption process for both activated carbons, and the kinetic performance of NAC was significantly higher than that of SAC. The calculated thermodynamic parameters of the adsorption process revealed that, under the conditions used in this study, the adsorption of chlortetracycline onto NAC is more feasible, spontaneous and endothermic than its adsorption onto SAC. Overall, the results indicated that, compared to SAC, NAC is a more suitable choice for removal of chlortetracycline antibiotic from aqueous solutions.

L-Tyrosine oxidative metabolism byStreptomyces aureofaciens

L-Tyrosine metabolism found in normal mammalian system via homogentisic acid was investigated inStreptomyces aureofaciens S-834 as L-tyrosine was shown to possess the stimulatory role in the production of chlortetracycline antibiotic. L-Tyrosine as well as the substrates of the intermediary oxidative enzymes-p-hydroxyphenylpyruvate (p-HPPA) hydroxylase and homogentisate (HGA) oxygenase were incubated with the washed, resting cells of the culture and by adding sodium diethyldithiocarbamate andα,α'-dipyridyl, the specific inhibitors of these enzymes to the culture, the oxidative intermediates-p-HPPA and HGA were blocked from further utilisation and were accumulated and isolated by extraction with the appropriate solvent system. The intermediates consisted of keto acids and aromatic phenolic acids were separated by adsorption and elution on silica gel and sephadex gel columns. p-HPPA and acetoacetate (AA) were identified as keto acids by obtaining their 2,4-dinitrophenylhydrazone derivatives. HGA as well as p-HPPA were identified as phenolic acids along with HGA lactone using diazotized reagents. These investigations helped to establish L-tyrosine oxidative pathway inStreptomyces aureofaciens via p-HPPA, HGA and AA leading to the biosynthesis of chlortetracycline antibiotic.