Simultaneous Cu(II) and Cr(VI) Removal by Single and Mixed Cultures of Indigenous Actinobacteria

A. RODRIGUEZ; A. E. ALVARENGA; V. L. COLIN; L. B. VILLEGAS; M. J. AMOROSO; C. M. ABATE

Puerto Vallarta

Congreso; 16th International Symposium on the Biology of Actinomycetes (ISBA16).; 2011

Heavy metal pollution is one of the most serious environmental problemsbecause they are not chemical and not biology degraded therefore they canremain for a long time in the nature. Microorganisms play a significant role inbioremediation of heavy metal contaminated soil and wastewater.Actinobacteria are known for their ability to colonize soil and they constitute asignificant component of the microbial population in it. Previous studies withactinobacteria reported the potential capacity of them, as tools for Cu(II), Cr(VI)or Cd(II) bioremediation. Normally soil or sediments present problems of cocontaminationwith various heavy metals.The results obtained leads us to study the possibility to use single and mixedcultures of actinobacteria for Cu(II) and Cr(VI) removal in liquid mediumsimultaneously.Amycolaptosis tucumanensis, Streptomyces sp. MC1, Streptomyces sp. F4isolated from contaminated sediments and characterized in before works andtwo new strains (called GHB and TC1) isolated from Tucumán, which alsoshowed heavy metal tolerant were used. Strains inhibition test were done ondifferent solid medium. TC1 showed inhibition activity in some medium.Therefore single and mixed cultures with and without TC1 were used. Cellswere incubated in Minimal Medium with glucose as only carbon source andsupplemented with 20 ppm of Cu(II) and Cr(VI). Cultures were incubated during144 h at 30 ºC and 160 rpm. Cells were harvested each 24 h and biomass wasdetermined by dry weight. Cr(VI) removal activity was measured by thecolorimetric method of 1,5-diphenylcarbazide and total chromium and copper byAtomic Absorption in the supernatant.Mixed Cultures without TC1 were more effective in Cr(VI) removal but did notshow significant differences on Cu(II) removal with single cultures.These results show that mixed cultures are a better tool than single cultures inCu(II) and Cr(VI) removal when they are at the same time.