American Journal of Chemistry

Isoeugenol's biotransformation to vanillin using microorganisms

Rupa Verma, Abhijit Dutta — Thu, 30 Jan 2025 00:00:00 -0600

The biotechnological route of producing natural biological food products is preferred over synthetically created ones. One such pathway is biotransformation, which entails the chemical transformation of one substance into another using microorganisms acting as biocatalysts. One crucial process in green chemistry is biotransformation, which results in the biological production of numerous valuable chemicals. Due to its distinct aroma, vanillin is one of the most widely used flavors in the world. It is used in ice cream, cakes, biscuits, chocolates, and cosmetics. Compared to chemically synthesized vanillin, biologically produced vanillin has very few or no radicals, which is why it has very little or no negative effects on humans. Biological precursors such as eugenol and isoeugenol, as well as ferulic acids, can be utilized in the production of vanillin. Pure bacterial cultures were isolated from soil (isolates coded as DSH1001 to DSH1004) and identified by various biochemical reactions as Gram-negative rods. The microorganism identified by 16S ribosomal sequencing with accession number OR140859 can convert isoeugenol to vanillin. Their capacity to biotransform isoeugenol was also investigated. Using HPLC, a final screening of the selected bacterial isolate was carried out at a temperature of 37°C, pH 7.2, agitation rate of 150 rpm, and an initial isoeugenol concentration of 0.01%. The food sector can profit from the commercial production of vanillin by biological means.

Preparation of carbon quantum dots biofilm and adsorption of heavy metal Cu2+

Jianting WEI — Fri, 14 Mar 2025 00:00:00 -0500

Currently, seawater is seriously polluted by Cu2+, thus the development of safe and efficient Cu2+ removal materials is important for maintaining the safety of marine ecology. In this study, we utilized reed and urea as raw materials, synthesizing carbon quantum dots (CQDs) and nitrogen-doped carbon quantum dots (N-CQDs) through the hydrothermal method. Then, we analyzed their performance in Cu2+ detection and absorbance. Both the CQDs and N-CQDs exhibited excellent fluorescent properties, with maximum excitation wavelengths at 325 nm and corresponding emission wavelengths at 400 nm. Nitrogen doping enhanced the fluorescence intensity and stability of CQDs. Various metal ions were tested for their fluorescence-quenching effects on CQDs and N-CQDs. The results indicated that the N-CQDs exhibited strong adsorption capacity towards Cu2+, showing a good linear relationship at Cu2+ concentrations ranging from 0 to 50 μmol/L with a detection limit of 1.081 μmol/L. Additionally, we prepared a CQDs-biofilm using 3% chitosan as raw material and evaluated the adsorption of Cu2+ by the N-CQDs biofilm. The findings revealed that the Cu2+ adsorption rate of the N-CQD biofilm ranged from 28% to 67%. This CQD-biofilm is significant for trace detection and pollution control of Cu2+ in aqueous media.

Spectroscopic determination of neodymium (III), praseodymium (III), samarium (III) and Terbium (III) in aqueous and micelle media using 2,2′- ((1E,1′E) - (1,4 phenylenebis (Azanylylidene)) Bis (Methanylylidene)) diphenol (BSPPD) as ligand

Mon, 25 Aug 2025 00:00:00 -0500

Lanthanide metals, as well as other heavy metals, are toxic and have an accumulative effect in biotic and abiotic organisms emanating from drug, electronic, glass, laser, electrical, nuclear, ceramic, and metallurgical industries. This study was carried out with the aim to use a simple, rapid and sensitive spectrophotometric method for the determination of Nd (III), Pr (III), Sm(III) and Tb(III) using the Schiff base 2,2′-((1E,1′E)-(1,4-phenylenebis (azanylylidene)) bis (methanylylidene)) diphenol (BSPPD). The objectives of this study were; to synthesize Nd(III), Pr(III), Sm(III) and Tb(III) complexes of BSPPD, to characterize the ligands and their metal complexes on the basis of melting point, conductivity, thermogravimetry, infra-red, nuclear magnetic resonance (1H and 13C) and UV-Visible spectroscopy and analyse the potentials of BSPPD as spectrophotometric reagents for Nd(III), Pr(III), Sm(III) and Tb(III) based on their interaction with Schiff bases. The analysis of the complexes formed in aqueous and micellar media was investigated in this study. Spectral and absorbance measurements were carried out using a UV-Visible Spectrophotometer (Jenway: 6305) with 1-cm matched quartz cells. The method of experiment used was based on the formation of dark brown coloured complexes upon the reaction of Nd(III), Sm(III), Tb(III) and reddish brown coloured complexes for Pr(III), with the highest absorbance of 368, 373, 372 and 374 nm, respectively. Beer’s law was obeyed from 0.001-0.02 ppm for aqueous medium and 0.001-0.01 ppm in micellar media as observed in this study. The molar absorptivity was observed within the ranges of 341-25993 dm³mol^-1cm^-1 for aqueous medium and 9601-84944 dm³mol^-1cm^-1 for micellar media.

Synthesis, characterization of 2-amino thiazol schiff base and its metal (II) complexes

Pessy, Hanson, Amadi, Jane Uchechi, Festus, Chioma — Tue, 11 Nov 2025 00:00:00 -0600

Metal(II) complexes of a Schiff base derived from 2-hydroxy-1-naphthaldehyde and 2-aminothiazole were synthesized through reactions with acetate salts of Zn(II), Co(II), and Ni(II). The resulting metal complexes were characterized using various analytical methods, including elemental analysis, molar magnetic susceptibility, and spectral techniques. Fourier-transform infrared (FTIR) spectroscopy of the free Schiff base (HL) revealed a characteristic band at 1620 cm⁻¹, attributed to the azomethine (C=N) functional group. In the metal complexes, this band shifted to the range of 1640–1642 cm⁻¹, indicating coordination through the azomethine nitrogen atom. UV-Visible (electronic) spectral analysis suggested that the complexes exhibit either octahedral or tetrahedral geometries, based on their electronic transition patterns. The ligand and its metal(II) complexes displayed solubility in common organic solvents such as ethanol, methanol, dimethyl sulfoxide (DMSO), and dimethylformamide (DMF), but showed limited solubility in chloroform and were insoluble in water. The synthesized complexes also exhibited high thermal stability, with melting points ranging from 225°C to 300°C. Visually, the metal complexes appeared in various shades of black, while the free Schiff base ligand was yellow in color. The values obtained for the Co(II), Ni(II), and Zn(II) complexes for molar conductance studies were 18.8, 11.9, and 29.6 Ω⁻¹·cm²·mol⁻¹, respectively are markedly lower, indicating non-electrolytic behavior in solution. Magnetic susceptibility data supported the proposed geometries and electronic configurations, confirming high-spin octahedral and tetrahedral arrangements for Co(II) and Ni(II), respectively, and diamagnetism for the Zn(II) complex.