The synthesis of silver nanoparticles (AgNPs) has been considered using microorganisms such as bacteria. These processes utilize eco-friendly, rapid, and cost-effective techniques. The present study focuses on the bacterial synthesis of AgNPs, their biological activity, and the efficiency of biodegradation of Disperse Blue 183. Twenty bacterial isolates were obtained from the Kashan textile industry effluent. Of these, a silver resistant (strain N) was selected to synthesize AgNPs. The biochemical, phenotypic characterization test and phylogenetic analysis based on comparing the 16SrDNA sequence determined that the strain N was 97.24% similar to Marinospirillum alkaliphilum. The strain N was able to synthesis silver nanoparticles. The AgNPs were characterized using UV–Vis spectroscopy, FTIR and XRD. The results of SEM-EDX confirmed the size of AgNPs within 30–70 nm range with a cubic shape. The results showed that AgNPs have as an antimicrobial effect against different standard and multi-drug resistant bacteria. The toxicity of AgNPs was evaluated using Artemia salina and recorded the LC₅₀ value (1 µg.ml⁻¹). Decolorization of Disperse Blue 183 was studied using immobilized AgNPs and AgNPs powder separately. The results showed that immobilized AgNPs decolorized Disperse Blue 183 with 100% efficiency. AgNPs powder and Ca-Alg beads have no decolorization ability.