Burkholderia bannensis sp. nov., an acidneutralizing bacterium isolated from torpedo grass (Panicum repens) growing in highly acidic swamps

Two strains of acid-neutralizing bacteria, E25 ^T and E21, were isolated from torpedo grass (Panicum repens) growing in highly acidic swamps (pH 2-4) in actual acid sulfate soil areas of Thailand. Cells of the strains were Gram-negative, aerobic, non-spore-forming rods, 0.6-0.8 μm wide and 1.6-2.1 μm long. The strains showed good growth at pH 4.0-8.0 and 17-37 °C. The organisms contained ubiquinone Q-8 as the predominant isoprenoid quinone and C _16:0, C _17:0 cyclo and C _18:1ω7c as the major fatty acids. Their fatty acid profiles were similar to those reported for other Burkholderia species. The DNA G+C content of the strains was 65 mol%. On the basis of 16S rRNA gene sequence similarity, the strains were shown to belong to the genus Burkholderia. Although the calculated 16S rRNA gene sequence similarity of E25 ^T to strain E21 and the type strains of Burkholderia unamae, B. tropica, B. sacchari, B. nodosa and B. mimosarum was 100, 98.7, 98.6, 97.6, 97.4 and 97.3%, respectively, strains E25 ^T and E21 formed a group that was distinct in the phylogenetic tree; the DNA-DNA relatedness of E25 ^T to E21 and B. unamae CIP 107921 ^T, B. tropica LMG 22274 ^T, B. sacchari LMG 19450 ^T, B. nodosa LMG 23741 ^T and B. mimosarum LMG 23256 ^T was 90, 42, 42, 42, 45 and 35%, respectively. The results of physiological and biochemical tests including whole-cell protein pattern analysis allowed phenotypic differentiation of these strains from previously described Burkholderia species. Therefore, strains E25 ^T and E21 represent a novel species, for which the name Burkholderia bannensis sp. nov. is proposed. The type strain is E25 ^T (=NBRC 103871 ^T =BCC 36998 ^T).