Growing Oyster Mushrooms (Pleurotus ostreatus) on PLA Plastic Compostable Cups and Straw: Biological Efficiency and Substrate Degradation


Taylor Chappell
Presented: Spring 2015
Committee: Steve Cartier, Mark Brenner, Langdon Martin

The average Amercian produces 4.41 pounds of waste per day, with the second largest waste item being containers and plastic, and only recycles 1.51 pounds of that daily value (US EPA, n.d.). This results in a 34% diversion rate for each person. With the amount of plastic recycled being so low, the creation of compostable plastic cups diverts a portion of this waste stream to becoming a reusable compost product. Although these cups breakdown in commercial facilites, they fail to do so in smaller operations resulting in the cups becoming a waste product. PLA plastic cups have the potential to be broken down with the help of oyster mushrooms. Oyster mushrooms have been grown on a variety of waste substrates in order to create an edible product (Mandeel et al., 2005). Thus, in order to help degrade the PLA plastic cups produced at Warren Wilson College campus oyster mushrooms were grown on a substrate consisting of the PLA plastic cups and straw. In order to determine the effectiveness of the cups as a substrate and their ability to be brokendown by the oyster mushrooms, biological efficency and cup degradation was measured for each of the fruiting treatments. In addition, % nitrogen and % crude protein, and carbohydrate content were also measured in order to determine whether or not the cups affected the nutritional value of the mushrooms. The highest biologic efficiency was for substrate composed of 50% PLA cups and 50% straw. The biological efficency was low due to a number of experimental constraints and human error. Stuff about degradation…. However, the % nitrogen, % crude protein, and carbohydrate content were within the normal limits for oyster mushrooms. For future experiments a substrate with a ratio of 50:50 cups to straw could be used for optimal growth of mushrooms with optimal time for cultivation.