%0 Journal Article %A Padden, A. Nikki. %A Dillon, Vivian M. %A Edmonds, John. %A Collins, M. David. %A Alvarez, Nerea. %A John, Philip. %T An indigo-reducing moderate thermophile from a woad vat, Clostridium isatidis sp. nov. %D 1999 %J International Journal of Systematic and Evolutionary Microbiology, %V 49 %N 3 %P 1025-1031 %@ 1466-5034 %R https://doi.org/10.1099/00207713-49-3-1025 %K indigo reduction %K Clostridium isatidis sp. nov. %K moderate thermophile %K phylogeny %I Microbiology Society, %X A Gram-positive, anaerobic, moderate thermophile, strain Wv6T, capable of reducing indigo dye, was isolated from a fermenting woad vat prepared essentially as in medieval Europe. Strain Wv6T formed rod-shaped cells, which occurred singly, in pairs or in chains and produced terminal oval endospores Strain Wv6T was saccharolytic. Growth occurred at pH 5.9-9.9 (initial pH) with an optimum at 50 °C of pH 7.2±0.2 (constant pH). At pH 7.8, the temperature range for growth was 30-55 °C with the optimum at 49-52 °C. Comparative 16S rRNA gene sequence analysis demonstrated that the bacterium represents a hitherto unknown subline within rRNA cluster I Clostridium. Based on the results of the phylogenetic analysis and phenotypic criteria, it is proposed that the unknown moderate thermophile should be classified as Clostridium isatidi sp. nov., a new species of the genus Clostridium. The type strain of Clostridium isatidis is strain Wv6T (= NCFB 3071T). %U https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/00207713-49-3-1025