Supplementation of first break mushroom compost with hydrolyzed protein, commercial supplements and crystalline amino acids

Abstract

Three mushroom (Agaricus bisporus) crops (Crops 1, 2, 3) were grown to evaluate the effects of re-supplementing “spent” first break compost [mushroom compost (MC)] on mushroom yield. Mushrooms were produced for one break at the Mushroom Test Demonstration Facility, the casing layer was removed and the MC was re-supplemented with hydrolyzed protein, commercial supplements and crystalline amino acids and then re-cased at the Mushroom Research Center. Sixteen supplements, including five crystalline amino acids, one amino acid blend, one egg white and four hydrolyzed proteins, Micromax® (a micronutrient containing nine minerals) and four commercial supplements were evaluated for their effect on mushroom yield and biological efficiency. In Crop 1, mushroom yields were stimulated (49–61%) when MC was re-supplemented with 3.6% (dry wt) Pro-Fam® H200 FG hydrolyzed soy protein, Remo’s commercial supplement, l-isoleucine (ile), egg white protein, amino blend HLA-198 and hydrolyzed whey. Significant yield reductions were observed for MC re-supplemented with 3.6% l-tyrosine, dl-methionine or l-arginine compared to the non-supplemented control. In Crop 2, mushroom yield ranged from a high of 31.3 kg/m2 on MC supplemented with 3.3% Remo’s + 0.3% ile (oven dry MC) to a low of 22.6 kg/m2 on non-supplemented (control) MC (38.5% difference). In Crop 3, a response surface model was used in an attempt to optimize combinations of Remo’s commercial supplement, ile and Micromax. The response surface solution for optimal yield was 2.9% Remo’s, 0.16% ile and 0.4% Micromax. Because many of the products tested performed equally well but varied substantially in their amino acid profiles, A. bisporus appears adaptable to different supplements containing both balanced and unbalanced amino acid contents, especially those rich in the branched chain amino acids. Development and improvement of supplements designed specifically for MC may allow further increases in productivity. Double cropping would ultimately lower the cost of mushroom production by reducing labor, raw materials and time required to prepare fresh Phase II compost.