The aim was to study the bioleaching performance of chemoheterotrophic bacterium involved in leaching of major, rare earth, and radioactive elements from red mud (RM), and to explore the underlying mechanism. An acid-producing bacterium, identified as Acetobacter sp., was isolated from RM impoundment and used in the bioleaching experiments under one-step, two-step and spent medium process at up to 10% pulp density. The results showed that the leaching ratios of Al, Lu, Y, Sc, and Th were 55%, 53%, 61%, 52%, and 53% respectively under one-step process at 2% pulp density. Under both one- and two-step processes at 2% pulp density, the radioactivity of bioleached RM can meet the relevant regulation in China. The total amount of organic acids excreted by Acetobacter sp. increased with an increase of RM pulp density. After bioleaching, contents of hematite and gibbsite decreased but perovskite increased in RM. Micromorphology analysis indicated that the cells of Acetobacter sp. adhered to RM particles and formed large-size aggregates, and a new crystal of weddellite emerged. In view of the shorter lag phase and smaller biomass comparing to fungi even under direct contact with RM, bacterium Acetobacter sp. is supposed to apply to in situ heap or dump bioleaching of RM.

The selected Moutai aromatic microorganisms and their metabolites were applied into the fermentation of tobacco leaves in order to improve the tobacco quality. The results showed that a variety of aromatic substances in Moutai, as well as the typical flavor substances commonly used in cigarettes, were detected in the fermented tobacco leaf extract. In view of the GC-MS results as well as the sensory smoking evaluation of tobacco leaf extracts under designed experimental conditions, the optimal parameters of stable single-strain fermentation process was at 40 ℃ for 10-15 days. The results of specific effects of different fermentation conditions on the content of aroma substances in different parts of tobacco leaves after fermentation, as well as the subsequent sensory evaluation, provided basic data for the improvement of tobacco fermentation and aroma flavoring technology, which was conducive to the development of new cigarettes.

The recovery of strategic metals (Sc, REEs, etc.) from red mud, a highly alkaline industrial solid waste, is severely hindered by silicate encapsulation and silica gelation during acid leaching. This study proposes a bio-desilication pretreatment using an acclimated strain of Bacillus mucilaginosus to address these challenges. Under optimized bio-desilication conditions, silicon leaching and desilication rates of 58.3% and 62.6% were achieved, respectively. Mechanistic investigations revealed that bacterial cells and their metabolites (organic acids and EPS) preferentially attack defect sites in aluminosilicate minerals, disrupting the Si–O network and liberating Si4+ and Al3+ ions, thereby driving extensive phase reconstruction, including dissolution of aluminosilicates (e.g., kaolinite, cancrinite), enrichment of stable minerals (e.g., hematite, rutile), and precipitation of secondary phases (e.g., calcite, calcium oxalate). This significantly enhanced subsequent metal leaching efficiencies in sulfuric acid, nitric acid, phosphoric acid, and Aspergillus niger bioleaching systems, with improvements ranging from 44.3% to 273%, while effectively suppressing silica gel formation. A preliminary economic analysis indicates a net benefit of ¥1,650 per ton of red mud, highlighting the potential of this sustainable bio-desilication strategy for valorizing silicate-bearing alkaline solid wastes.