Balasubramanian Arunraj

Atmospheric methane (CH4) acts as a key contributor to global warming and a short-lived climate forcer. CH4 mitigation represents the most promising means to address short-term climate change. Ruminant enteric CH4 produced by methanogenic archaea represents 27.2% of global CH4 emissions. Only a few of the direct methanogenesis inhibitors identified bear high mitigation potential hence it is important to investigate their underlying modes of action. Here, we elucidated biophysical and thermodynamic interplay between known inhibitors and cofactor F430, to determine their stoichiometric ratios and binding affinities. We leverage this prior in a robust contrastive learning approach to functionally cluster known sixteen inhibitors and 53,959 bovine-linked metabolites. We demonstrate a multi-factor optimization protocol to identify putative inhibitors with: (i) high bacterial membrane permeability, (ii) no adverse effect to ruminal fermentation, (iii) known degradation pathway, and (iv) direct commercial availability. Subsequent in vitro assays and community metabolic modeling with a first set of eight treatment molecules revealed structo-metabolic priors that tie thermodynamic signatures of inhibition to metabolic flux shifts. We established a multi-scale workflow that transforms ostensibly negative compounds into mechanistic insight, linking rumen metabolic flux shifts to MCR–F430-Ni(I) inhibition chemistry as a foundation for rational methane-mitigation design. COVER

The mounting demand for rare earth elements (REEs) and the similarities in their chemical and physical properties render their separation and selective recovery quite challenging. Microbe-based adsorbents are quite effective owing to their diverse functional groups on the cell wall and are perceived to be environmentally benign. This work reports the application of yeast (Saccharomyces cerevisiae) embedded in cellulose matrix as an efficient adsorbent for the separation of Eu(III) from aqueous medium. The fungi–biopolymer combination acts as a good host to welcome Eu(III) on its surface through effective coordination with the diverse functional groups. The pH, adsorbent dosage, isotherm studies, and thermodynamic and kinetic parameters were studied, and the characterization was done using FT-IR, XRD, XRF, XPS, SEM-EDX, BET, and confocal microscopy techniques. Ion chromatography was used to monitor the quantitative measurement of Eu(III) during the course of adsorption and desorption process. The regeneration of the biosorbent was achieved using EDTA as the complexing agent for Eu(III). The biosorbent gives a maximum adsorption capacity of 25.91 mg g^–1 through Langmuir isotherm model. Further, the biosorbent was employed to recover Eu(III) from a phosphor powder containing other rare earths as well as phosphor powder from a spent fluorescent lamp.

The current study deals with the utility of Saccharomyces cerevisiae (yeast) immobilized in glutaraldehyde cross-linked chitosan matrix for the removal of Eu(III) from aqueous solution. The biosorbent was characterized using FT-IR, SEM-EDX, XRD, TGA, and XPS analysis. Experimental variables that influence the adsorption were studied and the concentration of Europium was determined by ion chromatography. At pH 5.0, the adsorption was spontaneous and endothermic in nature. The biosorbent gave a Langmuir adsorption capacity of 19.41 mg g⁻¹ and followed pseudo second-order kinetics. The regeneration of biosorbent was achieved using potassium thiocyanate and the method showed good selectivity.