Carbohydrate source affects the synthesis of silver nanoparticles by 1449 and 1313.

Strains of have been used for the synthesis of metallic nanoparticles. Since the carbohydrate source could influence the yield and size of the synthesised nanoparticles, the authors evaluated the potential of 1449 and 1313 to produce silver nanoparticles (AgNPs) using three carbohydrate sources and AgNO. The presence of AgNO in the medium extended the duration of the acceleration and logarithmic phases of the two strains independently of the carbohydrate source used but did not inhibit their growth. The synthesis of AgNPs started at the second day of culture. In general, the size of the AgNPsranged from 10 to 150 nm; they were smaller and more homogeneous in lactose. In the medium supplemented with glucose, there was a lower production of nanoparticles for both strains. The AgNPs synthesised by 1313 remained enclosed in an extracellular polymeric substance, which probably played an important role in the synthesis of the nanoparticles. The carbohydrate source influenced the yield and size of the AgNPssynthesised by 1449 and 1313; the pH was also important for obtaining nanoparticles of uniform size.