Selecting and Characterizing Bacterial Consortia with the Potential of Fixing CO_2 and Removing H_2S in a Biogas Atmosphere

摘要

Biogas must be pretreated before its use; thus, both physical and chemical methods have been implemented to remove the fuel's principal pollutants (CO_2 and H_2S). Additional removal methods that use microorganisms' biological processes to eliminate pollutants have also emerged. A selection was made from six bacterial isolates to obtain consortia that removed CO_2 and eventually H_2S through the enrichment of cultures and the construction of clone libraries of gene 16S ribosomal DNA (rDNA). The results indicate that the principal differences between consortia were determined in the culture medium. C5 and C6 consortia had photosynthetic biomass 1.42 and 1.52 μg/ml, respectively, and concentration of dissolved CO_2 100.6 and 99.1 mg/l, respectively. The clone libraries showed that Rhodopseudomonas sp. had percentages 46.6, 42.5, and 86.8 % in C4, C5, and C6, respectively; Xanthobacter sp., 24.5 %, Castellaniella sp., 18 % in C5, and Sphingobium sp., 39.2 % in C4.