Removal of Cadmium and Lead from Contaminated Soils Using Sophorolipids from Fermentation Culture of Starmerella bombicola CGMCC 1576 Fermentation

Abstract

Soil contaminated with Cd and Pb has caused sharp decrease of cultivatable soil and has been attracting increasing attention. Biosurfactants are efficient in solving the problem. However, little information is available about the influence of sophorolipids (SLs) on the remediation of Cd- or Pb-contaminated soil. The sophorolipids produced by Starmerella bombicola CGMCC 1576 were used to study the effects of Cd and Pb removal in batch soil washing from artificially contaminated soil. The removal efficiency of crude total SLs was better than both distilled water and synthetic surfactants. Furthermore, 83.6% of Cd and 44.8% of Pb were removed by 8% crude acidic SLs. Acidic SLs with high water solubility were more effective than lactonic SLs in enhancing remediation of heavy metal-contaminated soils. The complexation of Cd with the free carboxyl group of the acidic SLs was observed by Fourier-transform infrared spectroscopy study, and this complexation was effective in heavy metal removal from the soil. The fermentation broth of S. bombicola, without further preparation, removed 95% of Cd and 52% of Pb. These results suggested that SLs produced by S. bombicola could function as potential bioremediation agents for heavy metal-contaminated soil.

Comparative Heavy Metal Removal Efficiencies of Biosurfactants Produced by Odoribacter Splanchnicus DSM 20712, Bacterium Clone JX981747 and Soil Washing Agents

“…Furthermore, the high rate of metal removal as observed in this study have shown that surfactants could remove metals by ion exchange precipitation, dissolution and counterion association with the crude sugar surfactant, depicting superior performance similar to previous reports (Mulligan et al, 1999, 2004and Qi et al, 2018. Generally, the concentration of biosurfactant have been observed to be a critical factor in uencing heavy metal removal e ciency in this study and elsewhere (Mulligan et al, 2001 andQi et al, 2018). E ciencies of biosurfactant and soil washing agents in heavy metal removal Mulligan et al, (1999) showed the feasibility of removing cadmium, lead, and zinc with 2% anionic biosurfactants surfactin from soil that is low in exchangeable metal fractions.…”

Heavy Metals and Pesticides Toxicity in Agricultural Soil and Plants: Ecological Risks and Human Health Implications

“…Pb has been listed as a hazardous heavy metal pollutant due to its high toxicity [72]. Long-term exposure to low concentrations of Pb leads to high toxic levels.…”

Microbial Surfactants: The Next Generation Multifunctional Biomolecules for Applications in the Petroleum Industry and Its Associated Environmental Remediation

“…The rhamnolipid-aided washing method was proven by Nielson et al [152] to be more efficient than a synthetic surfactant (carboxymethyl-β-cyclodextrin). A sophorolipid-enhanced soil washing method was used to remove 83.6% of Cd and 44.5% of Pb by Qi et al [153]. However, in the presence of sophorolipid-producing Starmerella bombicolla , the removal increased to 95% of Cd and 52% of Pb.…”