Enhanced silver nanoparticle synthesis by optimization of nitrate reductase activity

Nanostructure materials are attracting a great deal of attention because of their potential for achieving specific processes and selectivity, especially in biological and pharmaceutical applications. The generation of silver nanoparticles using optimized nitrate reductase for the reduction of Ag+ with the retention of enzymatic activity in the complex is being reported This report involves the optimization of enzyme activity to bring about enhanced nanoparticle synthesis Response surface methodology and central composite rotary design (CCRD) were employed to optimize a fermentation medium for the production of nitrate reductase by Bacillus licheniformis at pH 8 The four variables involved in the study of nitrate reductase were Glucose, Peptone, Yeast extract and KNO3 Glucose had a significant effect on nitrate recluctase production. The optimized medium containing (%) Glucose: 1 5, Peptone 1, Yeast extract 035 and KNO3 035 resulted in a nitrate reductase activity of 452 206 U/ml which is same as that of the centi al level The medium A (showing least nitrate recluctase activity) and the medium B (showing maximum nitrate reductase activity) were compared for the synthesis. Spectrophotometric analysis revealed that the particles exhibited a peak at 431 nm and the A431 for the medium B was 2-fold gi eater than that of the medium A The particles were also characterized using TEM. The particles synthesized using the optimized enzyme activity ranged from 10 to 80 nm and therefore can be extended to various medicinal applications (C) 2009 Elsevier B V All rights reserved.