This document presents algae-derived antimicrobial fiber substrates, and a method of making the same. The fiber may be a synthetic fiber, but can also be formed as a cellulosic (e.g., cotton). In various implementations, an algae-derived antimicrobial fiber substrate can be made to have identical properties and characteristics of nylon-6 of nylon 6-6 polymer or the like, and yet contain antimicrobial, anti-viral, and/or flame retardant algal derived substances. Any of various species of red algae, brown algae, blue-green algae, and brown seaweed (marine microalgae and/or macroalgae) are known to contain a high level of sulfated polysaccharides with inherent antimicrobial, antiviral, and flame-retardant properties, and can be used as described herein. Additionally disclosed are algae-derived flexible foams, whether open-cell or closed-cell, with inherent antimicrobial, antiviral, and flame resistant properties. Further, a process of manufacturing is presented wherein the process may include one or more of the steps of: harvesting algae-biomass; sufficiently drying the algae biomass; blending the dried algae biomass with a carrier resin and various foaming ingredients; adding an algal-derived antimicrobial compound selected from various natural sulfated polysaccharides present in brown algae, red algae, and/or certain seaweeds (marine microalgae); and adding a sufficient quantity of dried algae biomass to the formulation to adequately create a fire resistant flexible foam material.