Bioremediation of Chromium (Vi) by a Microbial Consortium Isolated From Tannery Effluents and Their Potential Industrial Application

Abstract

West Bengal has several leather industries and as such huge amount of leather are processed every year. The tannery effluents are discharged into the land and open water causing soil and water pollution respectively. Chromium is one of the most toxic inorganic contaminants which is well known for its carcinogenicity. Thus, our study focuses on investigating the bioremediation potential of common microflora isolated from tannery wastewater. In our study, Isolate 1 has the highest ability to reduce chromium (Cr6+) as compared to others. Isolate 4 has the highest protease, lipase and leather degradation activities. Isolate 1 shows the maximum keratinase activity making it an effective strain for keratinase production. Also, it has been found that pH 8 and temperature 40 °C was most suitable for keratinase production. Owing to the multidimensional ability of these two isolates, they were identified by 16S rRNA sequencing and it reveals that Isolate 1 and Isolate 4 belong to Bacillus cereus F4810/72 and Brevibacillus brevis F4810/72 respectively. Thus, this study establishes the role and efficiencies of these microorganisms in combatting pollution, particularly in the water bodies in which harmful chemicals leak regularly owing to improper waste management by various industries.

A Study on multiple isotherms of Cr6+ions usingBrevibacillus brevisUS575 isolated from tannery effluents

“…Study by Bhattacharjee et al showed the proficiency of Brevibacillus brevis US575 in reducing Cr 6+ to Cr 3+ [14]. The bacteria isolated from water samples were subjected to serial dilution technique in dilutions ranging from 10 -1 to 10 -4 .…”

“…All the four colonies were taken and sub-cultured separately to obtain further pure cultures. Results by Bhattacharjee et al, have also demonstrated the ability of Brevibacillus brevis US575 in degrading leather [14]. Thus this isolate was taken for preparing biomass and to understand its adsorption isotherms, amongst which the authors have adopted the Langmuir and Freundlich isotherms.…”

“…Also, the bacteria have been found to degrade not only chromium but also produces different industrially important enzymes like protease, lipase and keratinase. But as the demand is huge, different methods are also adopted to curtail these environment related issues [14]. In specific, biosorption possesses itself to be a common yet prominent and economical method to remove metal ions present in industrial effluents before release into waterbodies, as it includes biological sources like algae, bacteria, fungi etc [15,16,17].…”