Biodegradation studies on fatty amines used for reverse flotation of iron ore

Bacteria present in effluents from the process of iron ore flotation were isolated and identified in an attempt to identify the microorganisms responsible for fatty amine degradation. Water samples collected at the tailings dam led to the identification of the bacterial species Serratia marcescens as the microorganism responsible for degradation, while in laboratory flotation conditions, a strain of Enterobacter cloacae was shown to be the biodegrading agent. Both S. marcescens and E. cloacae are Gram-negative, non-sporulated, mobile and facultative anaerobic bacteria. Monitoring of the effluent had shown that after 5 days, around 34% of amine was already consumed, increasing to 75% after 10 days; these data are important for testing the reuse of the fatty amines contained in effluents. Biodegradation experiments carried out with S. marcescens revealed the significant role of temperature and concentration on the biodegradation rate of the etheramine EDA 3B. For the concentration of 10 mg L−1, amine biodegradation rates are very close at all temperatures. However, as amine concentration increases, the influence of temperature can be better observed, mainly for concentrations of 40 and 60 mg L−1. This isolate will be potentially useful in biotreatment of wastewaters and bioremediation of contaminated soils.