Biotechnology & nanotechnology
Mahta Majdnia; Maryam Sadrnia; Fatemeh Shahbazi; Nooshin Sohrabi
Abstract
Introduction: One of the best ways to remove toxic metals is to use bacteria resistant to these metals with biological purification process. The aim of this research is to isolate bacteria resistant to tin, copper, chromium and nickel from industrial wastewater and their molecular identification.
Materials ...
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Introduction: One of the best ways to remove toxic metals is to use bacteria resistant to these metals with biological purification process. The aim of this research is to isolate bacteria resistant to tin, copper, chromium and nickel from industrial wastewater and their molecular identification.
Materials and methods: First, wastewater contaminated with heavy metals was collected from electroplating factories located in Tehran province. The wastewater sample was cultured on LB Agar containing certain concentrations of heavy metals and the grown bacteria were isolated. On the grown bacteria, the minimum growth inhibitory concentration (MIC) of heavy metals was determined by the microbroth dilution method. Genomic DNA of two strains with the highest level of resistance, purity and polymerase chain reaction was performed with the help of specific primers. The PCR product was sequenced and ribotyping was done.
Results: 9 gram positive and negative bacilli and gram negative coccobacilli were isolated from wastewater containing heavy metals. Two Gram-negative bacillus strains showed the highest resistance to heavy metals in the MIC test. Based on the sequencing results, these two strains were identified as Enterobacter and Pseudomonas.
Conclusion: Two strains with the highest resistance to four metals were isolated from the effluent of electroplating factories and phylogenetic evaluation was performed. These bacteria can be used in the biological treatment of wastewater containing heavy metals.
Biotechnology & nanotechnology
Naimeh Khazali; Maryam Sadrnia; Reza Hajihosseini
Abstract
Background: Microbial lipases are an important group of enzymes with biotechnology value. In the present research, an attempt was made to isolate and identify lipase-producing microbial strains from industrial wastewater samples.Materials and Methods: After taking samples from sewage and sewage from ...
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Background: Microbial lipases are an important group of enzymes with biotechnology value. In the present research, an attempt was made to isolate and identify lipase-producing microbial strains from industrial wastewater samples.Materials and Methods: After taking samples from sewage and sewage from different places,16 colonies were isolated from these samples. The isolates were cultured in a specific culture medium containing Tween80 to check the ability to produce lipase enzyme. Enzyme activity was determined using the light absorption curve. In order to identify the isolates molecularly, ribotyping was performed. For this purpose, the DNA of the isolates was extracted and PCR was performed with the help of 16SrRNA gene primers. The PCR product was sequenced and the strains were identified using sequence blast in the NCBI database.Results: Out of a total of 16 isolates, ten strains (62.5%) were able to produce lipase enzyme as a result of creating a transparent halo in the culture medium of the lipid test. Among these, two isolates with the same halo formation rate and source of isolation, which had the highest growth and activity after 144 hours were selected from the culture. Enzyme activity values for bacteria isolated from slaughterhouse effluent and garage effluent ranged from 2.99 to 22.65 and 3.73to 39.2 units/ml, respectively.Conclusion: Due to their very high lipase activity compared to the strains introduced in other researches, Aeromonas veroni and Copriavidus metallidurans bacteria are suggested as very suitable and efficient strains for the biological treatment of wastewater.