پديدآورندگان :
احمدي اسب چين سلمان مازندران، بابلسر، پرديس دانشگاه مازندران، دانشكده علوم پايه، گروه ميكروبيولوژي , ديوسالار علي مازندران، بابلسر، پرديس دانشگاه مازندران، دانشكده علوم پايه، گروه ميكروبيولوژي , رضايي احمد شركت دانش بنيان سكانداران فرداي وركا قو، مازندران،دانشگاه مازندران، مركز رشد واحدهاي فناور دانشگاه.
چكيده لاتين :
With the expansion of industrialization in the modern world and modern agricultural methods, environmental pollution by heavy and toxic metals has increased and their accumulation in ecosystems, especially water ecosystems, has brought severe risks to the health of humans, animals, plants, microorganisms, as well as the environment. Biological methods called bioremediation have advantages over other physico-chemical methods, which can be mentioned as economical, environmentally friendly, and not producing polluted waste. Bacteria are considered among the most widely used adsorbents due to their ubiquity and resistance to various environmental conditions. In this research, it deals with the isolation of bacterial isolates from various places, including: the effluent of the sausage and sausage factory in Golestan province, Lavij hot spring in Mazandaran province, the industrial factory in Sari city of Mazandaran province, which have the ability to uptake heavy metals cadmium, nickel and lead. Then, the optimization process of biological absorption includes parameters such as: temperature, concentration of metals, amount of bacteria, pH. In the following, the removal of these metals by the isolates was optimized using the Response Surface Methodology (RSM). Finally, the package (Bioreactor) was designed to place these optimized bacteria. These bacterial isolates were studied from the point of view of morphology, biochemical and phylogeny, and 12 isolates were selected from about 40 isolates in the first stage. Based on biochemical, morphological, and molecular results, this isolate was close to Bacillus genus. According to the minimum inhibitory concentration test and the antibiogram of the selected Bacillus bacteria, this isolate was resistant to a concentration of 1500 ppm of cadmium, 2200 ppm of nickel and 2400 ppm of lead and also showed resistance to a wide range of antibiotics. The parameters of temperature, contact time, pH level, initial concentration of cadmium, nickel and lead and the amount of biomass on the absorption of three metals by Bacillus cell biomass have been studied. The results showed that the optimum pH for the removal of cadmium, nickel and lead metals by the isolated Bacillus bacteria was 6.5, 5.5 and 5.7 respectively. The biosorption efficiency of cadmium, nickel and lead metals was 0.72, 0.63 and 0.36 mmol/g, respectively. The temperature for removing cadmium and nickel metal by Bacillus bacteria was about 45 degrees Celsius and for lead metal was about 30 degrees Celsius. The adsorption isotherm for all three metals is similar to the Langmuir isotherm, which shows that the surface adsorption process is single-layer, its kinetics was according to the second-order kinetic model, and the amount of Bacillus bacteria biomass for this process was about 1.5 g/liter. At the end of this research, a bioreactor was designed for this process, and the steps of absorption in this bioreactor were also investigated.
