Impact of Light Spectra and Substrate Composition on the Bioefficiency, Nutritional Content, and Morphology of Oyster Mushrooms

Mushrooms are commercially cultivated in controlled environment agriculture facilities in which the parameters of temperature, humidity, and CO2 are closely controlled. In contrast to plant production, variable lighting is generally not a parameter that mushroom producers utilize. In this study, P. ostreatus, the pearl oyster mushroom, was cultivated under one of three LED light spectra: blue (450 nm), red (625 nm), or white (broad spectrum) at an intensity of 5 μmol m−2 s−1. Substrates used for production consisted of a 70/30 mixture of straw/cottonseed or straw/mesquite bean pod, all of which were locally sourced in Arizona. Bioefficiency (BE), nutrient profile, and morphology were assessed post-production. Light spectra had no significant effect on BE, beta glucan, total amino acids, or total antioxidant content. However, red light exposure increased the number of caps per cluster by 197% and reduced cap diameter by 55%. The straw/cottonseed substrate significantly increased BE by 77% over the straw/mesquite substrate, increased levels of total protein by 9%, and increased levels of glutamic acid, arginine, and histidine by 11%, 24%, and 33% respectively. Interestingly, the straw/mesquite substrate resulted in a significant increase in total amino acid and beta glucan content over the straw/cottonseed substrate by 8 and 18%, respectively. These results illustrate how light spectra and substrate mixture can significantly impact nutritional value and production qualities of oyster mushrooms.