Production of bioemulsifiers by Amycolatopsis tucumanensis DSM45259 and their potential application in remediation technologies forsoils contaminated with hexavalent chromium

Abstract

In recent years, increasing interest has been shown in the use of bioemulsifiers as washing agents thatcan enhance desorption of soil-bound metals. However, high production costs derived from the useof expensive substrates for formulation of the fermentation media represent the main challenge forfull, large-scale implementation of bioemulsifiers. This work reports on a first study of bioemulsifierproduction by the actinobacterium Amycolatopsis tucumanensis DSM 45259 using different carbon andnitrogen sources. Preliminary results on the potential use of these compounds as washing agents for soilscontaminated with Cu(II) and Cr(VI) are also presented. The best specific production was detected usingglycerol and urea as carbon and nitrogen substrates, respectively. However, with all of the substratesused during the batch assay, the bioemulsifiers showed high levels of stability at extreme conditions ofpH, temperature, and salt concentration. Under the current assay conditions, the bioemulsifiers werenot effective in removing Cu(II) from soil. However, they were able to mediate Cr(VI) recovery, with theremoval percentage doubled compared to that seen when using deionized water. These findings appearpromising for the development of remediation technologies for hexavalent chromium compounds basedupon direct use of these microbial emulsifiers.