The synthesis and comparative study on the antibacterial activity of three organotin(IV) compounds, namely dibutyltin(IV) bis-(3-hydroxybenzoate), [Bu2Sn(3-HBz)2] (7), diphenyltin(IV) bis-(3-hydroxybenzoate), [Ph2Sn(3-HBz)2] (8), and triphenyltin(IV) 3-hydroxybenzoate, [Ph3Sn(3-HBz)] (9) which were prepared by the reaction of dibutyltin(IV) oxide, [Bu2SnO] (4), diphenyltin(IV) dihydroxide, [Ph2Sn(OH)2] (5), and triphenyltin(IV) hydroxide, [Ph3SnOH] (6) with 3-hydroxybenzoic acid (3-HBz) has successfully been performed. The characterization of these compounds were done using 1H and 13C NMR, IR, UV spectroscopies and their compositions were determined based on microanalytical data. Antibacterial activity of these compounds was demonstrated at concentrations of 1.89 × 10−4, 1.81 × 10−4, and 1.72 × 10−4 M, respectively by dilution method against Pseudomonas aeruginosa. Similarly, the compounds were active at concentration of 1.87 × 10−4, 1.79 × 10−4, and 1.71 × 10−4 M, respectively, against Bacillus subtilis. These activities are comparable to that of streptomycin at a concentration of 1.70 × 10−4 M as a positive control, but the halozone of compounds 7, 8, and 9 were slightly lower than that of streptomycin’s halozone. The results obtained suggest that the compounds synthesized have potential as antibacterial agents.
The research aims to study the effect of chemical modification on the stability of protease enzyme from a local bacteria isolate B. subtilis ITBCCB148 with NPC-PEG. The result showed that the native enzyme has optimum pH and temperature of 6.5 and 60C, respectively. The stability test of the native protease at pH 6.5 and temperature 60C for 360 minutes produce the following results: the residual activity of 5.75%, t½= 84.5 min., k i = 0.0082 min. . The modified enzyme with NPC-PEG (33%, 42%, and 75%), showed that the optimum pH did not changed, however, the optimum temperature shifted from 60C to 65C. The stability tests of the modified enzyme with NPC-PEG have increased of 2.06; 2.24; and 2.31 times, respectively, than that of the native one. The decrease of ki, the increase of t½ and ∆G i of the modified enzymes with NPC-PEG demonstrated that upon modification, the enzyme became more stable. This might due to rigidity increase of the modified enzyme, so the active structure of the enzyme is maintained and is protected from unfolding process.
In this research, it has been evaluated concentration effect of Cd 2+ ion used as the Cd From the adsorption data obtained, they show that initial concentration differences of the imprinted Cd 2+ ion produce different adsorption models of the Cd 2+ ion. The bigger the Cd 2+ ionic imprinting fraction, the higher the adsorption rate (k 1 ) and capacity (q) of Cd 2+ ion on the adsorbent.
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