Pleurotus ostreatoroseus DPUA 1720: avaliação do crescimento, produção de basidioma e determinação da atividade proteolítica em resíduos agroindustriais

Abstract

Mushrooms arouse interest for presenting high nutritional and medicinal value. The representatives of the genus Pleurotus are able to grow in different agricultural and agro-industrial waste, since they secrete numerous enzymes that hydrolyze the substrates prepared from waste providing nutrient The search for alternative substrates increased in recent years due to the availability of regional waste little or never used in the production of edible mushrooms. The use of waste in solid-state fermentation has emerged also in the production of enzymes. Proteases are a group of enzymes commercially exploited, however the use of Basidiomycetes as producers of proteases is still a relatively unexplored. The aim of this study was to evaluate the mycelial growth as well as to investigate the production and partially characterize extracellular proteases from Pleurotus ostreatoroseus DPUA 1720 in different agro-industrial waste, selecting a mixture for the production of the mushroom and check their microbiological quality and nutritional value. Cultures were prepared in potato dextrose added yeast extract 0.5% (w/v). The vertical mycelial growth and production of proteases from P. ostreatoroseus DPUA 1720 were performed in agro-industrial waste (acai seed, sawdust, cupuassu bark, rice bran, bark and pineapple crown) for 15 days under two growing conditions (presence and absence of light). The production of basidiomata was performed in the substrate which presented satisfactory mycelial growth and vigorous mycelium. From this bioprocess evaluated the formation and development of early basidiomata, total time of cultivation, biological efficiency, productivity, production rate, loss of organic matter, microbiological and nutritional value of the mushroom. P. ostreatoroseus DPUA 1720 grew in all industrial residues also tested serving as sources for the production of proteases. In bark cupuaçu added rice bran mycelium was strongly vigorous and the mycelial growth satisfactory, therefore selected for the production of P. ostreatoroseus DPUA 1720. Under the experimental conditions the proteolytic activity was determined in crude extracts from the substrates of vertical mycelial growth with maximum proteolytic activity (7.89 U/mL) in bark cupuassu added rice bran in the presence of light. This substrate was the most efficient for the production of proteases with activity atpH 6.0 and optimum temperature at 40 ˚C. The basidiomata showed no contaminants, low in fat, high in fiber and protein, macro and micro minerals, essential and non-essential amino acids, may therefore be inserted into the feed as a safe and nutritious food.