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

Abstract

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 ALET) that is able to use a great variety of substrates including glycerol. Strain ALET 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 Propionispora hippei (91.4% 16S rRNA gene identity) from the Sporomusaceae family (Selenomonadales order, Negativicutes class, Firmicutes phylum). Based on the distinctive physiological and phylogenetic characteristics of strain ALET, a new genus and species Lucifera butyrica gen. nov., sp. nov., is proposed. The type strain is ALET (=JCM 19373T = DSM 27520T). Strain ALET is an incomplete oxidizer and acetate, among other products, accumulates during glycerol conversion. Strain ALET was used to extend the substrate range for sulfur reduction by constructing co-cultures with the acetate oxidizer and sulfur reducer Desulfurella amilsii. The co-culture was tested with glycerol as substrate in batch and chemostat experiments. Acetate formed by fermentation of glycerol by strain ALET resulted in sulfur reduction by D. amilsii. 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.Note: The locus tag for the genes encoded in Lucifera butyrica is LUCI_∗. To avoid repetition of the prefix along the text, the locus tags are represented by the specific identifier.

Acetate Degradation at Low pH by the Moderately Acidophilic Sulfate Reducer Acididesulfobacillus acetoxydans gen. nov. sp. nov.

“…The ability to use acetic acid as electron donor is advantageous in extreme environments such as AMD for several reasons. Firstly, acetic acid is a typical end product of other microorganisms such as fermenters present in AMD sediments ( Sánchez-Andrea et al, 2018 ). The ability to metabolize a variety of organic acids, but especially a metabolic end product such as acetic acid ( Table 1 ) increases the carbon and energy available to strain INE in nutrient-limited AMD/ARD environments.…”

Insight Into Interactions of Thermoacidophilic Archaea With Elemental Sulfur: Biofilm Dynamics and EPS Analysis

“…Current global production consists of 15% copper, 5% gold and smaller amounts of other metals using biomining technologies (Johnson, 2014). Unintended metal sulfide dissolution results in serious environmental problems such as acid mine drainage (AMD) or acid rock drainage (ARD) (Hallberg, 2010). Various sulfur intermediates are formed through either thiosulfate or polysulfide pathways during MS dissolution (Vera et al, 2013).…”

Pontiella desulfatans gen. nov., sp. nov., and Pontiella sulfatireligans sp. nov., Two Marine Anaerobes of the Pontiellaceae fam. nov. Producing Sulfated Glycosaminoglycan-like Exopolymers

“…tested in this study. As an example, the reduction of elemental sulfur has also been observed for thermophilic archaea [73], several Planctomycetes [74][75][76] and the firmicute Lucifera butyrica [77], without a noticeable effect on the growth rate or yield. The Kiritimatiellales strains possessed no genes encoding proteins that could facilitate anaerobic respiration of sulfur compounds, such as polysulfide reductase or other types of molybdoenzymes [78], dissimilatory (bi)sulfite reductase pathway proteins or other reductive proteins listed by Wasmund, et al [79].…”