Substrate disinfection methods on the production and nutritional composition of a wild oyster mushroom from the Amazon

Abstract

One of the most expensive steps in mushroom production is the disinfection of the substrate. This study aimed to evaluate different methods of disinfecting various substrates used in the cultivation of Pleurotus ostreatus from the Amazon. P. ostreatus was grown under uncontrolled temperature conditions in a greenhouse (at approximately 30 °C) on substrates formulated with residues (seeds) of açaí and tucumã palm trees, Brazil nuts shell and pine sawdust. The different substrate disinfection treatments comprised autoclaving, immersion in hot water or immersion in calcium hydroxide (2%). The chemical composition of residues, substrates, and mushrooms was analyzed. During cultivation, it was found that in the treatment with hot water, all the bags were contaminated, and treatment with calcium hydroxide inhibited the colonization and growth of the mushrooms. P. ostreatus grown on the autoclaved açaí substrate supplemented with tucumã had higher production. The highest percentage of fiber content was obtained when the mushrooms were cultivated in the pine substrate supplemented with Brazil nuts (32.68 to 33.65%), and the highest protein content (20.03 to 20.88%) was found in the mushrooms grown on açaí-based substrates. Considering that P. ostreatus showed higher productivity in autoclaved substrates, further studies should be performed to develop alternative methods of disinfecting substrates for the cultivation of mushrooms in the Amazon region, as well as, in other regions with a tropical climate. However, the cultivation of this mushroom is promising using some regional substrates, especially with açaí, which is one of the important natural products of the Amazon.