Electrospinning is a fabrication process that uses an electric field to control the deposition of polymer fibers onto a target substrate. Nanofiber possess the characteristic features of high length-to-diameter ratio and specific surface areas, enabling it to be used for protective clothing, filter, antibacterial membrane, reinforced composite, and tissue engineering. We have adopted a method of direct in situ electrospinning to produce mats composed of the culture filtrate from low shear modeled microgravity (LSMMG) grown Penicillium chrysogenum with a suitable carrier polymer to aid in its electrospinning. The antibacterial activity of the mat is attributed to the presence of penicillin in the culture filtrate. The presence of penicillin was confirmed by using liquid chromatography–mass spectrometry (LC–MS/MS). The mat was found to be effective against gram positive bacteria like Staphylococcus aureus and Enterococcus faecalis. The process, stability and characterization of the biological properties of such nanofibrous scaffolds are demonstrated.