Effect of selected heavy metals on the growth performance and yield of commercially cultivated American oyster mushroom Pleurotus ostreatus

Mushrooms can accumulate heavy metals from the growth substrates. This study compared the growth and yield performances of commercially grown American Oyster mushrooms (Pleurotus ostreatus) in the presence of different heavy metals in the substrate. The substrate of the mushroom media contained different heavy metals (Cadmium (Cd), Lead (Pb), Arsenic (As), and Mercury (Hg)) in three concentration levels (25, 50, and 75 mg/kg of sawdust). An experiment was carried out in a Complete Randomized Design (CRD) with five replicates. Both growth parameters (total biological efficiency, total colonization time, time for primordial formation, number of fruiting bodies in the first flush, and weekly mycelium growth rate) and yield parameters (weight and the total number of fruiting bodies) of the mushroom were recorded. Three flushes were made during the study period from October to December 2016. All the data were analyzed statistically using ANOVA (p<0.05) and Duncan’s multiple range test by SAS statistical software (version 9.1.3). The results revealed that biological efficiency of Cd, Hg, and Pb metal concentrated mycelium showed significantly higher values at all three different concentration levels compared to As that lowest at 75 mg/kg concerted level. The highest time of primordial formation, the highest total colonization time, and numbers of fruiting body’s development in the first flush was observed at 75 mg/kg level as treated substrate. Further studies are required to find the bioaccumulation of the heavy metal in the mushrooms.