Growth, respiratory activity and chlorpyrifos biodegradation in cultures of Azotobacter vinelandii ATCC 12837

This study aimed to evaluate the growth, respiratory activity, and biodegradation of chlorpyrifos in cultures of Azotobacter vinelandii ATCC 12837. A strategy based on the modification of culture media and aeration conditions was carried out to increase the cell concentration of A. vinelandii , in order to favor and determine its tolerance to chlorpyrifos and its degradation ability. The culture in shaken flasks, using sucrose as a carbon source, significantly improved the growth compared to media with mannitol. When the strain was cultivated under oxygen-limited (5.5, 11.25 mmol L- 1 h- 1 ) and no-oxygen-limited conditions (22 mmol L -1 h -1 ), the growth parameters were not affected. In cultures in a liquid medium with chlorpyrifos, the bacteria tolerated a high pesticide concentration (500 ppm) and the growth parameters were improved even under conditions with a reduced carbon source (sucrose 2 g L -1 ). The strain degraded 99.6 % of chlorpyrifos at 60 h of cultivation, in co-metabolism with sucrose; notably, A. vinelandii ATCC 12837 reduced by 50% the initial pesticide concentration in only 6 h (DT 50 ).

Keratinocyte cellular damage induced by pesticide doses below the cytotoxic level evidenced by electrical impedance and broadband dielectric spectroscopy

Cellular response of a normal human keratinocyte cell line exposed to non-cytotoxic doses of a deltamethrin-based pesticide was investigated by means of two different electrical impedance data spectroscopy approaches: Nyquist plot and broadband dielectric spectroscopy. The measurements have shown that the membrane capacity increases with pesticide concentration and this facilitates the electric current through cell membranes. Furthermore, the impedance of the extracellular matrix also increases with pesticide concentration, thus reducing the electric current outside the cell. Dielectric permittivity changes in the cellular samples at frequency larger than 100 Hz. Fluorescence measurements emphasized an increase of neutral membrane lipids as consequence of the pesticide exposure. Comparison of fluorescence response of pesticide exposed cells with the control ones showed a time increase of the emission intensity, suggesting the existence of a membrane lipid response aimed at repairing of the cell damage due to pesticide exposure. Therefore, both the spectroscopic techniques have demonstrated to be potential means to investigate the response to cell stress and damage. This opens up new possibilities in the early diagnosis of cellular modifications related to pesticides exposure of cells.

Growth, respiratory activity and chlorpyrifos biodegradation in cultures of Azotobacter vinelandii ATCC 12837

This study aimed to evaluate the growth, respiratory activity, and biodegradation of chlorpyrifos in cultures of Azotobacter vinelandii ATCC 12837. A strategy based on the modification of culture media and aeration conditions was carried out to increase the cell concentration of A. vinelandii, in order to favor and determine its tolerance to chlorpyrifos and its degradation ability. The culture in shaken flasks, using sucrose as a carbon source, significantly improved the growth compared to media with mannitol. When the strain was cultivated under oxygen-limited (5.5, 11.25 mmol L−1 h−1) and no-oxygen-limited conditions (22 mmol L−1 h−1), the growth parameters were not affected. In cultures in a liquid medium with chlorpyrifos, the bacteria tolerated a high pesticide concentration (500 ppm) and the growth parameters were improved even under conditions with a reduced carbon source (sucrose 2 g L−1). The strain degraded 99.6% of chlorpyrifos at 60 h of cultivation, in co-metabolism with sucrose; notably, A. vinelandii ATCC 12837 reduced by 50% the initial pesticide concentration in only 6 h (DT50). Graphical Abstract

EFEKTIVITAS PESTISIDA ORGANIK EKSTRAK KULIT JERUK NIPIS TERHADAP KEMATIAN JANGKRIK

Pestisida organik adalah pestisida yang bahan dasarnya berasal dari tumbuhan yang bersifat mudah terurai di alam. Salah satu tumbuhan yang dapat dijadikan bahan baku pembuatan pestisida organik adalah kulit jeruk nipis. Kulit jeruk dapat berpotensi menjadi repellent karena mengandung minyak atsiri dengan komponen limonene, mirsen, linalool, oktanal, decanal, sitronelol, neral, geraniol, valensen dan sinensial. Linalool, sitronelol dan geraniol termasuk senyawa yang bersifat repellent terhadap serangga (arthropoda). Pengunaan bahan alami dari ekstrak kulit jeruk diharapkan lebih aman jika dibandingkan dengan bahan kimia Dichloro Diphenyl Trichloroethane (DDT). Proses pembuatan pestisida organik dilakukan dengan ekstraksi maserasi menggunakan ethanol sebagai pelarut. Dalam penelitian ini bertujuan untuk mengetahui pengaruh variabel terhadap hasil pengujian pestisida organic terhadap jangkrik. Hasil penelitian menunjukkan pada konsentrasi pestisida organic 5% didapatkan prosentase kematian jangkrik 72%, pada konsentrasi 15% didapatkan prosen kematian jangkrik 80%, dan pada konsentrasi 25% didapatkan prosen kematian jangkrik 88%. Hasil penelitian menunjukkan bahwa adanya pengaruh terhadap perbedaan konsentrasi pestisida organic terhadap kematian jangkrik. Kata kunci: jeruk nipis, maserasi, pestisida organik AbstractOrganic pesticides are pesticides whose basic ingredients come from plants that are easily biodegradable in nature. One of the plants that can be used as raw material for making organic pesticides is lime peel. Orange peel can potentially be a repellent because it contains essential oils with components of limonene, mirsen, linalool, octanal, decanal, citronellol, neral, geraniol, valensen and sinensial. Linalool, citronellol and geraniol are compounds that are repellent to insects (arthropoda). The use of natural ingredients from orange peel extract is expected to be safer when compared to the chemical Dichloro Diphenyl Trichloroethane (DDT). The process of making organic pesticides is done by maceration extraction using ethanol as a solvent. This study aims to determine the effect of variables on the results of testing organic pesticides on crickets. The results showed that at 5% organic pesticide concentration, 72% of crickets died, at 15%, 80% of crickets died, and at 25%, 88% of crickets died. The results showed that there was an effect on differences in the concentration of organic pesticides on the mortality of crickets.. Keywords: lime, maceration, organic pesticide

A new Fe3O4/CuO/AC Nanocomposite for Imidacloprid Removal: Characterization, Optimization, and Adsorption Modeling

A new magnetic adsorbent (Fe3O4/CuO/AC) composed of magnetite (Fe3O4) and copper oxide (CuO) nanoparticles Impregnated with activated carbon (AC) has been fabricated and used for the first time to remove imidacloprid (IMCP) insecticide from the aqueous solutions. This composite was characterized using field emission scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, energy dispersive x-ray diffraction, and vibrating sample magnetometer. The main influential factors such as the solution pH, the adsorbent amount, temperature, agitating time, and initial pesticide concentration were also tested to evaluate the optimized condition. Based on the results obtained from isotherm and kinetic modeling, the adsorption mechanism of IMCP on Fe3O4/CuO/AC is a combination of physisorption and chemisorption phenomena. The experimental data fitted best to the Freundlich isotherm model revealing the presence of heterogeneous sites for IMCP adsorption. Besides, the kinetics results revealed that the adsorption process well fitted with pseudo-second-order model, implying that the chemisorption was determining step in adsorption process. Thermodynamic results showed the spontaneous and exothermic nature of the adsorption process. Under optimal conditions (pH 7; contact time, 10 min; initial pesticide concentration, 10 mg L-1), IMCP removal efficiency was 99.6%, indicating the excellent ability of Fe3O4/CuO/AC nanocomposite for the adsorption of this pesticide from water solutions.

Process optimization and enhancement of pesticide adsorption by porous adsorbents by regression analysis and parametric modelling

In the present study, the adsorptive removal of organophosphate diazinon pesticide using porous pumice adsorbent was experimentally investigated in a batch system, modelled and optimized upon response surface methodology (RSM) and artificial neural network-genetic algorithm (ANN-GA), fitted to isotherm, kinetic and thermodynamic models. The quantification of adsorbent elements was determined using EDX. XRD analysis was utilized to study the crystalline properties of adsorbent. The FT-IR spectra were taken from adsorbent before and after adsorption to study the presence and changes in functional groups. The constituted composition of the adsorbent was determined by XRF. Also, the ionic strength and adsorbent reusability were explored. The influences of operational parameters like pH, initial pesticide concentration, adsorbent dosage and contact time were investigated systematically. ANN-GA and RSM techniques were used to identify the optimal process variables that result in the highest removal. Based on the RSM approach, the optimization conditions for maximum removal efficiency is obtained at pH = 3, adsorbent dosage = 4 g/L, contact time = 30 min, and initial pesticide concentration = 6.2 mg/L. To accurately identify the parameters of nonlinear isotherm and kinetic models, a hybrid evolutionary differential evolution optimization (DEO) is applied. Results indicated that the equilibrium adsorption data were best fitted with Langmuir and Temkin isotherms and kinetic data were well described by pseudo-first and second-order kinetic models. The thermodynamic parameters such as entropy, enthalpy and Gibbs energy were evaluated to study the effect of temperature on pesticide adsorption.

RISK ASSESSMENT OF PESTICIDE INTAKE WITH LOCAL FOOD PRODUCTS FOR ADULT HEALTH OF THE CITY OF КAZAN

The current study was carried out to access the effect of DDT and HCH contaminated local food consumption on the adult population of Kazan city. Unexpectedly, the computations considered outcomes for a wide range of food items that are covered by the dietary admission model have hazard appraisal. The degrees of non-cancer-causing hazards for the strength of the grown-up populace related with the complex entry of DDT and HCCH at the median (Ме) level and the level of the 95th percentile with the basic food groups are identified. The ongoing dietary danger evaluation and at the degree of the 95th Percentile showed that the likelihood of Tatarstan inhabitants being presented to pesticide buildup levels that could prompt high (HI =13.41) negative wellbeing results. Such high levels of risk need urgent actions on the decrease of pesticide concentration and imply the development and implementation of planned curative measures.