The effect of different nitrogen sources on mycelial growth of oyster mushroom, Pleurotus ostreatus : with a review concerning cultivation of the species

Abstract: The production of Oyster mushroom, Pleurotus ostreatus, is sustainable, both in terms of economy and environment. Cultivation can be performed successfully on a wide range of substrates, often in the form of otherwise non-productive waste from other industries, such as agriculture and forest production. In a literary review results of studies on the fungi and its possible substrates are examined. Pleurotus is efficient in breaking down lignocellulosic wastes and its requirements on substrates for cultivation are therefore quite modest. Nonetheless many conditions can be regulated in order to optimise the mushroom production. Some general conclusions are made on what type of improvements the mushroom producer or scientist can make in terms of creating a better substrate. Experiments were made on three strains of P. ostreatus (M 2140 and M2191 from Mycelia, Belgium, and ATCC® 44309™ from ATCC, USA). The aim is to test a chemically defined medium and a variation in nitrogen sources in it with reference to radial mycelial growth and mycelial thickness. The results show growth on all media tested and the radial mycelial growth and thickness was observed to significantly differ depending on the available nitrogen source for three strains of P. ostreatus. Overall the control medium, which had a higher nitrogen content and more complex ingredients, reached the best results for both parameters. Another result is that mixtures of ammonium and the amino acid asparagine were preferred over mixtures including nitrate for all three strains. Some strain variations were observed and from this one may conclude that the requirements of the specific strains differ. This illuminates the importance of clearly presenting the strains used in future studies. Furthermore, it is suggested to either create a strain specific substrate or “train”/adapt the specific strain for a specific substrate. Further studies are needed for an improved understanding of P. ostreatus and its nutritional requirements and cultivation. In the future, additional research can improve this and the gaps in knowledge will hopefully be filled.