In the present study, poly(vinyl alcohol) (PVA) - Acacia lignin (PL) nanofiber mats loaded with silver nanopartides were prepared and characterized. In-situ synthesis of silver nanoparticles was accomplished using alkali lignin extracted from Acacia wood as a reducing agent. Ultrafine nanofiber mats of PL incorporated with silver nanoparticles were fabricated using the electrospinning technique. The fiber morphology of the resultant nano fiber was characterized using scanning electron microscopy. The average diameter of the nanofiber was in the range of 100 to 300 nm. The existence of silver nanopartides was confirmed by X-ray diffraction analysis. The influence of silver nanoparticles on the polymer structure was investigated by mechanical and thermal properties analysis. The antimicrobial activity of the PL nanofibers containing silver nanoparticles was tested against Bacillus circulans (MTCC 7906) and Escherichia coli (MTCC 739) and showed significant results against both microorganisms. The results revealed that PL nanofiber containing silver nanoparticles may have potential applications as membrane filtration, antimicrobial fabrics and wound dressing material. (C) 2018 Elsevier B.V. All rights reserved.