## 3 Results and Discussion
At the same time, the interplanar distances present in the diffraction patterns correspond to the indexing of face-centered cubic unit cells of silver and silver chloride crystals. It can be seen that the predominant crystallographic growth planes are (111), (200), (220), (311), (222), (400) and (420) for AgCl NPs, due to a larger number of brighter points in their structure. Diffraction planes corresponding to the Ag crystals found most commonly in the nanoparticles synthesized using microorganisms are (111) and (220), according to the 00-004-0783 XRD standard. By increasing the NaCl concentration, the presence of silver crystals could be suppressed, forming the desired AgCl configuration [36]. Figure 1: (**A**) Colloids with Ag/AgCl nanoparticles (NPs); (**B**) UV-visible spectra of colloids with Ag/AgCl nanoparticles, biosynthesized by _Raoultella planticola_ and _Pantoea agglomerans_. Figure 3: (**A**) Transmission electron microscopy (TEM) images of silver chloride nanoparticles (scale bar: 50 nm) and (**B**) selected area electron diffraction (SAED) pattern of Ag/AgCl nanoparticles biosynthesized by (**1**) _Raoultella planticola_ and (**2**) _Pantoea agglomerans_. Figure 2: X-ray diffraction (XRD) patterns for Ag/AgCl nanoparticles biosynthesized by Gram-negative bacteria from the Enterobacteriaceae family. Ag/AgCl NPs synthesized using _Raoultella_ bacteria were smaller (in the 10-30 nm range according to TEM analysis) (Figure 3A-1). _Pantoea_ bacteria mediated the synthesis of silver chloride nanoparticles of a wider size range; their spherical shape and dimensions reached up to 50 nm and can be observed in Figure 3A-2. SEM analysis (Figure 4A) confirmed the formation of spherical nanoparticles. The SEM microscopy images suggest that the diameter of the silver chloride nanoparticles ranges from 10-50 nm. The EDS spectra (Figure 4B) indicate the existence of the main elements, specifically Ag and Cl, alongside other contaminant elements that can be observed in the samples as a result of the preparation method (copper grid, carbon band, and platinum thin film which was deposited in order to increase the secondary electrons emitted from the surface of the specimen). This situation can be avoided by sample calcination before sample mounting. As a complementary analysis in terms of shape, for nanoparticles biosynthesized by _Raoultella_ _planticola_ and _Pantoea agglomerans_, spherical nanoparticles can be observed (Figure 5). The obtained images confirmed that spherical particles were obtained that had a moderately rough surface and a diameter of approximately 60 nm on average. The size of the obtained particles was slightly different than that obtained from TEM and SEM  
Figure 4: Scanning electron microscopy (SEM) images (**A**) and energy dispersive spectroscopy (EDS) spectra (**B**) of Ag/AgCl NPs nanoparticles biosynthesized in the presence of (**1**) _Raoultella_ and (**2**) _Pantoea_ extracts. measurements, which is expected considering that the geometry of the tip could lead to a change in the lateral dimensions of the nanoparticle, as in AFM. As a result, it is hard to determine the real diameter of the nanoparticles in an accurate manner. This technique was mainly used to provide images of the nanoparticles in terms of shape at an atomic level resolution by measuring the topography of the sample [37; 38]. Figure 5 illustrates an AFM image representative of the silver chloride nanoparticles synthesized due to the bio-reduction activity of the microorganisms. Generally, smaller-sized nanoparticles are supposed to exhibit increased antimicrobial potential. Apart from the spherical shape of silver/silver chloride nanoparticles [7], different configurations have also been reported in the literature. Ag/AgCl core-shell structure nanowires, nanocubes, and ellipsoids were synthesized using mostly chemical methods [36; 39]. An in-depth analysis should be performed to see if the elongated shape is the result of the aggregation of two or more particles [34].