Circular Economy Approach: Cultivating Grey Oyster Mushroom using Cassava (Manihot esculenta) Peel Waste from Starch Production

Abstract

Cassava (Manihot esculenta) is an important staple crop in Vietnam and is estimated to produce about 10.7 million tons of starch annually. The starch production process generates a large amount of solid waste, namely cassava peels, which are currently disposed of directly into the environment. This practice poses a risk of generating foul odor, attracting disease-carrying organisms, and directly affecting human health. Therefore, reusing cassava peels for growing gray oyster mushrooms is the most appropriate solution. First and foremost, the cyanide content in cassava peels must be treated using the Sun-drying method. Results showed that the cyanide level decreased to the optimal level of 0 mg/kg from 34 mg/kg. After reusing cassava peels to grow gray oyster mushrooms, the results showed that the highest yield was 272 g/bag for cassava peels substrate, while the highest yield for sawdust substrate was 293 g/bag. Statistical evaluations showed that reusing cassava peels to replace sawdust substrate for growing gray oyster mushrooms also resulted in an equivalent yield. Utilizing the substrate after growing mushrooms on cassava peels to grow cabbage produced a germination rate and plant height development equivalent to those grown on commercial fertilizer substrate.