Project description:Acidithiobacillus ferrooxidans (A. ferrooxidans) ATCC 23270 is a model bacteria for bioleaching research. Because of the use of extractant in metal extraction industry, A. ferrooxidans needs to cope with the water-organic two-phase system. To get insight into the molecular response of A. ferrooxidans to organic solvent, global gene expression pattern was examined in A. ferrooxidans ATCC 23270 cells subjected to Lix984n (an organic extractant) using the method of whole-genome DNA microarray. The data suggested that the global response of A. ferrooxidans to Lix984n stress was characterized by the up-regulation of genes involved in pentose phosphate pathway, fatty acid and glutamate biosynthesis contrary to the significant down-regulation of the majority motility-related genes. In further study, compared to heterotrophic bacteria in dealing with short-time stress, A. ferrooxidans has a special strategy of continuously enhancing the expression of genes encoding proteins involved in electron transport, such as petI, petII, cyo and cyd. Besides, acrAB-tolC operon encoding organic solvent efflux pump and its positive regulator gene ostR were addressed.
Project description:Transcriptomic study of A. ferrooxidans was explored either during aerobic growth with sulfur as an electron source and oxygen as final electron acceptor or in anaerobic conditions with ferric iron as the final electron receptor. Differential RNA levels were related to changes in cellular functions that were used to develop a preliminary model for A. ferrooxidans electron transport during dissimilatory ferric iron reduction.
Project description:Full title: Environmental transcriptome analysis of LfeRT32a in its natural microbial community comparing the biofilm and planktonic modes of life. Extreme acidic environments are characterized among other features by the high metal content and the lack of nutrients (oligotrophy). Macroscopic biofilms and filaments usually grow on the water-air interface or under the stream attached to solid substrates (streamers). In the Tinto River (Spain), brown filaments develop under the water stream where the Gram-negative iron-oxidizing bacteria Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans are abundant. Both microorganisms play a critical role in bioleaching processes for industrial (biominery) and environmental applications (acid mine drainage, bioremediation). The aim of this study was to investigate the physiological differences between the free living (planktonic) and the sessile (biofilm associated) lifestyles of L. ferrooxidans as part of a natural extremely acidophilic community.
