AUTHOR=Sánchez-Andrea Irene , Florentino Anna Patrícya , Semerel Jeltzlin , Strepis Nikolaos , Sousa Diana Z. , Stams Alfons J. M. 

TITLE=Co-culture of a Novel Fermentative Bacterium, Lucifera butyrica gen. nov. sp. nov., With the Sulfur Reducer Desulfurella amilsii for Enhanced Sulfidogenesis

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.03108

DOI=10.3389/fmicb.2018.03108

ISSN=1664-302X

ABSTRACT=<p>Biosulfidogenesis can be used to remediate low pH and high metal content waters such as acid mine drainage and recover the present metals. The selection of a cheap electron donor for the process is important for the economic viability. In this work we isolated a novel versatile acidotolerant fermentative bacterium (strain ALE<sup>T</sup>) that is able to use a great variety of substrates including glycerol. Strain ALE<sup>T</sup> is an obligate anaerobe, and cells are motile, rod-shaped, spore-forming, and stain Gram-positive. Growth occurred in a pH range from 3.5 to 7 (optimum 5.5), and temperature range from 25 to 40°C (optimum 37°C). It grows by fermentation of sugars, organic acids and glycerol. It has the ability to use thiosulfate, iron and DMSO as electron acceptors. Its genome is 4.7 Mb with 5122 protein-coding sequences, and a G+C content of 46.9 mol%. Based on 16S rRNA gene sequence analysis, the closest cultured species is <italic>Propionispora hippei</italic> (91.4% 16S rRNA gene identity) from the <italic>Sporomusaceae</italic> family (<italic>Selenomonadales</italic> order, <italic>Negativicutes</italic> class, <italic>Firmicutes</italic> phylum). Based on the distinctive physiological and phylogenetic characteristics of strain ALE<sup>T</sup>, a new genus and species <italic>Lucifera butyrica</italic> gen. nov., sp. nov., is proposed. The type strain is ALE<sup>T</sup> (=JCM 19373<sup>T</sup> = DSM 27520<sup>T</sup>). Strain ALE<sup>T</sup> is an incomplete oxidizer and acetate, among other products, accumulates during glycerol conversion. Strain ALE<sup>T</sup> was used to extend the substrate range for sulfur reduction by constructing co-cultures with the acetate oxidizer and sulfur reducer <italic>Desulfurella amilsii.</italic> The co-culture was tested with glycerol as substrate in batch and chemostat experiments. Acetate formed by fermentation of glycerol by strain ALE<sup>T</sup> resulted in sulfur reduction by <italic>D. amilsii</italic>. The co-culture strategy offers good perspectives to use a wide range of cost-efficient substrates, including glycerol, to produce sulfide by specialized sulfur reducers. The recovery of heavy metals from metalliferous streams may become economically feasible by this approach.</p><p><bold>Note:</bold> The locus tag for the genes encoded in <italic>Lucifera butyrica</italic> is LUCI_<sup>∗</sup>. To avoid repetition of the prefix along the text, the locus tags are represented by the specific identifier.</p>