Project description:Many trees form ectomycorrhizal symbiosis with fungi. During symbiosis, the tree roots supply sugar to the fungi in exchange for nitrogen, and this process is critical for the nitrogen and carbon cycles in forest ecosystems. However, the extents to which ectomycorrhizal fungi can liberate nitrogen and modify the soil organic matter and the mechanisms by which they do so remain unclear since they have lost many enzymes for litter decomposition that were present in their free-living, saprotrophic ancestors. Using time-series spectroscopy and transcriptomics, we examined the ability of two ectomycorrhizal fungi from two independently evolved ectomycorrhizal lineages to mobilize soil organic nitrogen. Both species oxidized the organic matter and accessed the organic nitrogen. The expression of those events was controlled by the availability of glucose and inorganic nitrogen. Despite those similarities, the decomposition mechanisms, including the type of genes involved as well as the patterns of their expression, differed markedly between the two species. Our results suggest that in agreement with their diverse evolutionary origins, ectomycorrhizal fungi use different decomposition mechanisms to access organic nitrogen entrapped in soil organic matter. The timing and magnitude of the expression of the decomposition activity can be controlled by the below-ground nitrogen quality and the above-ground carbon supply.
Project description:The carbonate leaching of scandium from the landfilled bauxite residue (red mud) of the Bogoslovsky Aluminum Plant (Russia) and samples of red mud (RM) after alkaline pretreatment has been investigated. The results of kinetic studies allowing to compare and evaluate the effectiveness of different conditions and intensification factors in the process of scandium leaching from RM in carbonate/bicarbonate media are presented. It was determined that for 2.0 mol L-1 Na2CO3 leaching solution ultrasonic treatment under gas (CO2) carbonation conditions in the pH range of 9.5-10.0 allows reducing the scandium leaching time by two times and reaching 40-45% scandium extraction. Leaching of RM in carbonate/bicarbonate media is accompanied by secondary processes (adsorption, hydrolysis, and coprecipitation) leading to a decrease in scandium extraction. The obtained results allow improving understanding of scandium chemical behavior in complex aqueous carbonate/bicarbonate systems and can be used for the optimization of the alternative carbonate process for scandium extraction from RM.
Project description:The fermented and distilled Chinese alcoholic beverage strong flavor baijiu (SFB) gets its characteristic flavor during fermentation in cellars lined with pit mud. Microbes in the pit mud produce many key precursors of flavor esters. The over 20 year maturation time of natural pit mud have promoted attempts to produce artificial pit mud (APM) with shorter maturation time. However, knowledge on the molecular basis of APM microbial dynamics and associated functional variation during SFB brewing is limited, and the role of this variability in high quality SFB production remains poorly understood. We studied APM maturation in new cellars till the fourth brewing batch using 16S rRNA gene amplicon sequencing, real-time quantitative PCR and function prediction based on the sequencing results, and metaproteomics and metabolomics techniques. The results provide insight into global APM prokaryotic dynamics and their role in SFB production, which will be helpful for further optimization of APM culture technique and improvement of SFB quality.