|1745-1||Physiological and molecular characterization of sulfate reducing bacterial consortia for use in bioremediation|
|Autores:||Jovanka Trebotich (USACH - Universidad de Santiago de Chile) ; Pablo Romero (USACH - Universidad de Santiago de Chile) ; Alfredo Monsalve (USACH - Universidad de Santiago de Chile) ; Aliosha Figueroa (USACH - Universidad de Santiago de Chile) ; Claudia Ortiz (USACH - Universidad de Santiago de Chile) ; Marcela Wilkens (USACH - Universidad de Santiago de Chile) |
Liquid wastes (LW) generated by the copper production process contain high sulfate concentrations (about 2,500 ppm) producing several environmental impacts. Since the chemical treatments of the LWs are very expensive, the biological approach using sulfate-reducing bacteria (SRB) along with plants that accumulate metals in wetland systems is more affordable. The aim of this study was to evaluate the sulfate reduction efficiency of different bacterial consortia and to characterize the microbiological communities at the molecular level.
Sulfate removal efficiency was evaluated using modified Postgate C media supplemented with vitamins with lactic acid as a carbon source. The most active consortia were selected to determine the sulfate reduction activity in a copper-mining LW using wheat straw as a carbon source and with no other supplementation. The consortia were previously adapted in Postgate C media and 20 % v/v of these cultures was used to inoculate the media. Activated sludge was also used to compare the sulfate reduction efficiency of the consortia. The sulfate reduction activity was assessed by the appearance of black precipitate and quantified by using a turbidimetric method with barium chloride. The bacterial community in each consortium was analyzed by amplifying and cloning 16SrDNA and by the subsequent analysis of 200 clones through restriction fragment length polymorphism (RFLP). The representative inserts of the libraries were sequenced and analyzed with BLAST, Bellerophone (chimeras) and EcoSim 7.71 program (rarefaction curve).
Consortia 4 and 8 showed the highest efficiency of sulfate reduction in modified Postgate C media with lactic acid as a carbon source. These consortia showed also sulfate reduction in the presence of wheat straw, and activated sludge was not active under this condition. Molecular analysis of the bacterial composition at family level, showed that the predominant genus was Clostridium (50 %) represented by the species C. sulfidigenes, C. thiosulfatireducens and C. bifermentans.
In conclusion, all the bacterial consortia showed an interesting sulfate-reducing activity when a copper-mine LW was used in the presence of wheat straw as the unique carbon source. The predominance of the genus Clostridium in all consortia analyzed is remarkable.
Funding: Innova-Chile Corfo Project 09CN14-5795
Palavras-chave: sulfate reduction, bacterial community analysis, RFLP