A target engagement assay to assess uptake, potency and retention of antibiotics in living bacteria

A major challenge in antibiotics drug discovery is to turn potent biochemical inhibitors of essential bacterial components into effective antimicrobials. This difficulty is underpinned by a lack of methods to investigate the physicochemical properties needed for candidate antibiotics to permeate the bacterial cell envelope and avoid clearance by the action of bacterial efflux pumps. To address these issues, here we used a target engagement assay to measure the equilibrium and kinetics binding parameters of antibiotics to their molecular targets in live bacteria. We validated this approach for a known antibiotic target, dihydrofolate reductase, using the Gram-negative bacteria Escherichia coli and the emerging human pathogen Mycobacterium abscessus. We expect the use of similar target engagement assays to expedite the discovery and progression of novel, cell-permeable antibiotics with on-target activity.

Efficacy of Alkaline-Treated Soy Waste Biomass for the Removal of Heavy-Metal Ions and Opportunities for Their Recovery

In this study, soy waste biomass (SW) resulting from oil extraction was treated with alkaline solution, and the obtained material (Na-SW) was used as biosorbent for the removal of Pb(II), Cd(II), and Zn(II) ions from aqueous media. The performance of this biosorbent was examined in batch systems, at different initial metal ion concentrations and contact times (pH 3.4; 5 g of biosorbent/L). Isotherm and kinetic modeling was used to calculate the equilibrium and kinetics of the biosorption processes. The maximum biosorption capacity, calculated from the Langmuir isotherm model, followed the order Zn(II) (0.49 mmol/g) > Cd(II) (0.41 mmol/g) ≈ Pb(II) (0.40 mmol/g), while the kinetics of biosorption processes fit the pseudo-second-order model. Three cycles of biosorption/desorption were performed to estimate the reusability of Na-SW biosorbent, and the regeneration efficiency was higher than 97% in all cases. The practical applicability of Na-SW biosorbent in treating of wastewater contaminated with Pb(II), Cd(II), and Zn(II) ions was examined using simulated wastewater samples, and the main quality characteristics of the effluents obtained after treatment were evaluated. All these aspects highlight the potential applicability of Na-SW for large-scale wastewater treatment.

Equilibrium & kinetic studies of reactive extraction of trans-aconitic acid using sunflower oil with tri-n-octylamine

In order to design an efficient extraction system for the separation of biochemically produced trans-aconitic acid (TAH) from fermentation broth; equilibrium and kinetics of reactive extraction of TAH from aqueous solutions was investigated using tri-n-octylamine (TOA) as an extractant and sunflower oil as a diluent. Through the equilibrium studies stoichiometry (acid, extractant) of complex formations was determined with the help of loading ratio. Formation of (1, 1), (2, 1), & (3, 1) stoichiometry complexes were observed having complexation constants values 179.73 kmol−1 m3, 9512.58 kmol−2 m6, and 614,407.02 kmol−3 m9, respectively. Kinetics experiments were performed in Lewis type stirred cell and results confirmed that reaction between TAH and TOA in sunflower oil fall in regime 1, i.e. slow reaction occurring in bulk organic phase. The overall order of reaction is pseudo first order with rate constant (K mn ) 1.78 × 10−5 (kmol m−3)−0.71 s−1 and physical mass transfer coefficient (K l ) 4.22 × 10−5 m s−1.

3D Printed PEI Containing Adsorbents Supported by Carbon Nanostructures for Post-combustion Carbon Capture From Biomass Fired Power Plants

Processes that utilize solid adsorbents to capture CO2 are promising alternatives to state-of-art Amine based technologies for capturing CO2 from large point sources. Although the energy needs of solid sorbent-based processes are low, the process footprint and consequently the capital cost connected to its implementation can be large due to the relatively long cycle times needed to get the required purity and recovery of the CO2 product. To overcome this challenge, processes having structured adsorbents like laminates, monoliths etc. are needed due to their low pressure drop and better mass transfer characteristics. The aim of this multiscale study is to evaluate the process-based performance of a 3D printed sorbent containing polyethyleneimine (PEI) and multiwalled carbon nanotubes (MWCNT) for capturing CO2 from a biomass fired power plant flue gas. A 6-step vacuum swing adsorption (VSA) cycle was simulated and optimized using equilibrium and kinetics data obtained from volumetry and breakthrough experiments. The optimization study showed that it was possible to achieve purity values >95% and recovery values >90% from dry CO2 feed streams containing 10 and 15% CO2 respectively. The minimum specific energy values were 0.94 and 0.6 MJ/kg and maximum productivity values were 0.8 and 2.2 mol/m3 ads s, respectively, for the two scenarios.