Here's what rhymes with feedstocks.

Consider these alternatives

biofuel / fuel biofuels / schools butanol / whole propylene / seen biotechnological / logical biodegradable / capable hydroelectricity / activity cellulose / close polypropylene / seen ethylene / seen methanol / alcohol ethanol / small emulsifiers / desires propellants / parents bioremediation / operation arsenide / side fermentable / double sugarcane / main