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Abstract: An alkalotolerant bacterial community was developed by continuous enrichment in the chemostat in presence of dibenzofuran (DF) as sole carbon source. Six different types of bacterial isolates were cultured on nutrient broth agar plates together with six operational taxonomic units (OTUs) at pH 7.0 and pH 8.0 by 16S rDNA-DGGE method. However, isolates of microbial community was declined from three OTUs (pH 9.0) to two at pH 10.0 after enrichment in alkaline condition. Among the six isolates tested for degradation of DF, Pseudomonas sp. and Bacillus sp. the members of alkalotolerant bacterial community had better potency to degrade dibenzofuran. Alkalotolerant bacterial community introduced in soil microcosm for evaluation of survival of most suitable isolates and degradation of dioxin-like compound indicated more than 90% degradation of dibenzofuran after 45 days by the bacterial community enriched for 180 days in the chemostat at pH 10, however, microbial community was not competent to utilize even 50% DF after day 30, not enriched in the chemostat. The survival of competent bacteria monitored by DGGE method in soil microcosm indicated presence of two major alkalotolerant isolates for utilization of dibenzofuran, substantiated the results and significance of alkalotolerant bacteria for in situ bioremediation of dioxin-like compounds in the environment. [Copyright &y& Elsevier]

Bacteria belonging to phylum Gemmatimonadetes comprise approximately 2% of soil bacterial communities. However, little is known of their ecology due to a lack of cultured representation. Here we present evidence from biogeographical analyses and seasonal quantification of Gemmatimonadetes in soils, which suggests an adaptation to low soil moisture. [ABSTRACT FROM AUTHOR]