Isolation and characterization of carcinogenic chromium reducing Pseudomonas aeruginosa from water of Buriganga river

Abstract

Hexavalent chromium is a highly toxic heavy metals which has the carcinogenic and mutagenic property. It is mobile in nature and causes many more diseases such as skin cancer, lung cancer, nasal infection etc. This hexavalent chromium is mainly used in diffrent industries like leather, tannery, dye, stainless steel etc. From these industries, chromium released in the environment without proper treatment which can be a dangerous for human and the environment. Hexavalent is more toxic than any other form of chromium.In this study, a bacterial strain was indentified named Pseudomonas aeruginosa which has the capability to reduce hexavalent chromium and produce trivalent form and show the resistance to Chromium. The strain was collected from Buriganga river and isolation was done in nutrient agar plates. Then purified the strain and used in different experiment such as DPCZ based bioassay. Bioassay method was used to find out their reduction capacity at three different temperature 25˚C, 37˚C, and 42˚C with three diffrentpH 5.5, 7, 8.5. From bioassay study, it was observed that the isolate has good Chromium reduction capacity at 37˚C pH 8.5 and 7. Highest reduction was found at 37˚C pH 8.5 which means the optimum reduction condition of the strain. It is also found from this study that the enzyme that bacteria used for reduction is exoenzyme. From this study it was also observed that this strain is mostly susceptible to Ciprofloxacin whereas strain is resistant to some other antibiotics such as Penicillin G, Amoxycillin, and Cefuroxime Sodium. MIC was also observed which showed that bacteria can tolerate upto 9mM of chromium concentration. Finally 16S rDNA squencing was used for identification and using the sequence data a phylogenetic tree was made which showed the similarity between the experimental strain and Pseudomonas aeruginosa.