Novel Methodology for Washing of Chromium Contaminated Soil Using Biosurfactant in Pakistan


  • Zahid Nawaz Center for Organic Chemistry, School of Chemistry, University of The Punjab, Lahore-54590, Pakistan
  • Farrukh Bashir Department of Chemistry, Sardar Bahadur Khan (SBK) Women’s University, Quetta-87300, Balochistan
  • Anam Sajid Department of Natural Sciences and Humanities, Faculty of NHS & IS, University of Engineering and Technology, Lahore, New Campus, KSK- 54590 Pakistan
  • Muhammad Shahid 4Center for Physical Chemistry, School of Chemistry, University of The Punjab, Lahore- 54590, Pakistan
  • Iftikhar Hussain Center for Physical Chemistry, School of Chemistry, University of The Punjab, Lahore- 54590, Pakistan
  • Muhammad Aamir Raza Pakistan Council of Scientific and Industrial Research Laboratories Complex, Quetta-87300, Pakistan
  • Farida Bhelil Department of Chemistry, Sardar Bahadur Khan Women’s University (SBKWU), Quetta, Pakistan
  • Musarat Riaz Department of Chemistry, Sardar Bahadur Khan (SBK) Women’s University, Quetta-87300, Balochistan



Biosurfactant, Bioremediation, Chromium, Heavy metals, Optimization, Pseudomonas aeruginosa, Rhamnolipid, Washing of soil, Waste treatment


Chromium is acutely toxic, mutagenic, and carcinogenic for all forms of life. Industrial sources release chromium thus contaminating water and soil. As biosurfactants are natural, easily degradable, non-toxic, environment-friendly, and cost-effective products, we have applied them here for bioremediation and prepared rhamnolipids as biosurfactants. Rhamnolipids were prepared by using Pseudomonas aeruginosa in mineral salt (MS) media at pH 7 and kept in an incubating shaker for 48 hours at 37oC. Centrifugation was used to extract the cells from the culture broth and cell-free broth was later used for washing the soil. K2Cr2O7 was used for soil spiking. By optimizing different variables like pH, time, concentration of chromium, dilution of rhamnolipids, and percentage removal of chromium was studied Best removal (89.25%) of chromium was obtained in 6 hours using 3:1 rhamnolipid dilution for 500 ppm of K2Cr2O7 at pH 4. However in some cases, after 24 hours, as rhamnolipid started releasing chromium, a decrease in chromium removal percentage has been observed which represents the mechanism shift from micelle remediation to reduction one and causes reduction of Cr+6 to insoluble Cr+3. Results of the present research suggested that microbial metabolites such as biosurfactants are found to be significantly efficient for the removal of chromium (89.25%) from the contaminated soil.


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