Beyond low lignin: Identifying the primary barrier to plant biomass conversion by fermentative bacteria.

Renewable alternatives for nonelectrifiable fossil-derived chemicals are needed and plant matter, the most abundant biomass on Earth, provide an ideal feedstock. However, the heterogeneous polymeric composition of lignocellulose makes conversion difficult. Lignin presents a formidable barrier to fermentation of nonpretreated biomass.

Engineering ethanologenicity into the extremely thermophilic bacterium Anaerocellum (f. Caldicellulosiriuptor) bescii.

The anaerobic bacterium Anaerocellum (f. Caldicellulosiruptor) bescii natively ferments the carbohydrate content of plant biomass (including microcrystalline cellulose) into predominantly acetate, H, and CO, and smaller amounts of lactate, alanine and valine. While this extreme thermophile (growth T 78 °C) is not natively ethanologenic, it has been previously metabolically engineered with this property, albeit initially yielding low solvent titers (∼15 mM).

Chalcopyrite bioleaching efficacy by extremely thermoacidophilic archaea leverages balanced iron and sulfur biooxidation.

Factors that contribute to optimal chalcopyrite bioleaching by extremely thermoacidophilic archaea were examined for ten species belonging to the order Sulfolobales from the genera Acidianus (A. brierleyi), Metallosphaera (M. hakonensis, M.

Phenotype-driven assessment of the ancestral trajectory of sulfur biooxidation in the thermoacidophilic archaea Sulfolobaceae.

Certain members of the family Sulfolobaceae represent the only archaea known to oxidize elemental sulfur, and their evolutionary history provides a framework to understand the development of chemolithotrophic growth by sulfur oxidation. Here, we evaluate the sulfur oxidation phenotype of Sulfolobaceae species and leverage comparative genomic and transcriptomic analysis to identify the key genes linked to sulfur oxidation. Metabolic engineering of the obligate heterotroph revealed that the known cytoplasmic components of sulfur oxidation alone are not sufficient to drive prolific sulfur oxidation.