Estimation of urinary delta aminolevulinic acid levels in gasoline and petrol pump workers as an index of lead exposure

Lead poisoning is a phenomenon which with growing globalization is being a subject of worry.ALA i.e Amino levulinic acid is a precursor of hemoglobin, which is synthesized in mitochondria by two main components succinyl Co-A and glycine in presence of ALA-S i.e. amino levulinic acid-synthase. Urinary ALA (ALA-U) has been a recommended biomarker for lead exposure. Inhibition of Amino levulinic acid-dehydratase (ALA-D) results into activation of ALA-S which further synthesizes ALA, excess of ALA is accumulated in the blood, plasma, urine. Present manuscript is focused on the estimation of levels of ALA in the urine of gasoline and pertol pump workers, by acidifying the urine to extract out ALA and reading it colorimetrically as they are exposed to fumes released by gasoline, petrol, and petroleum products which contains lead. Awareness and safety measures such as protective masks and gears should be provided by the respective organisations to the workers.

Ru@hyperbranched Polymer for Hydrogenation of Levulinic Acid to Gamma-Valerolactone: The Role of the Catalyst Support

Hydrogenation of levulinic acid (LA) obtained from cellulose biomass is a promising path for production of γ-valerolactone (GVL)—a component of biofuel. In this work, we developed Ru nanoparticle containing nanocomposites based on hyperbranched pyridylphenylene polymer, serving as multiligand and stabilizing matrix. The functionalization of the nanocomposite with sulfuric acid significantly enhances the activity of the catalyst in the selective hydrogenation of LA to GVL and allows the reaction to proceed under mild reaction conditions (100 °C, 2 MPa of H2) in water and low catalyst loading (0.016 mol.%) with a quantitative yield of GVL and selectivity up to 100%. The catalysts were successfully reused four times without a significant loss of activity. A comprehensive physicochemical characterization of the catalysts allowed us to assess structure-property relationships and to uncover an important role of the polymeric support in the efficient GVL synthesis.

A Sustainable Approach for Synthesizing (R)-4-Aminopentanoic Acid From Levulinic Acid Catalyzed by Structure-Guided Tailored Glutamate Dehydrogenase

In this study, a novel enzymatic approach to transform levulinic acid (LA), which can be obtained from biomass, into value-added (R)-4-aminopentanoic acid using an engineered glutamate dehydrogenase from Escherichia coli (EcGDH) was developed. Through crystal structure comparison, two residues (K116 and N348), especially residue 116, were identified to affect the substrate specificity of EcGDH. After targeted saturation mutagenesis, the mutant EcGDHK116C, which was active toward LA, was identified. Screening of the two-site combinatorial saturation mutagenesis library with EcGDHK116C as positive control, the kcat/Km of the obtained EcGDHK116Q/N348M for LA and NADPH were 42.0- and 7.9-fold higher, respectively, than that of EcGDHK116C. A molecular docking investigation was conducted to explain the catalytic activity of the mutants and stereoconfiguration of the product. Coupled with formate dehydrogenase, EcGDHK116Q/N348M was found to be able to convert 0.4 M LA by more than 97% in 11 h, generating (R)-4-aminopentanoic acid with >99% enantiomeric excess (ee). This dual-enzyme system used sustainable raw materials to synthesize (R)-4-aminopentanoic acid with high atom utilization as it utilizes cheap ammonia as the amino donor, and the inorganic carbonate is the sole by-product.

Insights into Cascade and Sequential one pot pathways for reductive amination of aldehydes paired with bio-derived levulinic acid to N-substituted pyrrolidones using molecular hydrogen

This work aims to explore cascade and sequential one pot syntheses pathways for N-substituted pyrrolidones from aryl aldehydes and bio-derived levulinic acid (LA) using molecular hydrogen and ammonia. This process...