No abstract

Supplementation of the spent oyster substrate enhances its nutritional properties to produce a new mushroom cropping cycle. The study investigated the potential of a nano-fertilizer (Lithovit®-Amino25) with an admixture of 25% l-amino acids on Pleurotus ostreatus production, proteins, and amino acid contents. The product applied at spawning (t1), after the first harvest (t2), and at both timings (t3), in two doses: 3 g/kg (C1) or 5 g/kg (C2). Compared with control (C0t0), the first harvest was earlier by 2.3–3.3 days in C1t1 and C2t1. The biological yield of the second harvest was improved by 28.0% in C2t2. Superior results were in C1t3 where the number of crops increased to four, biological efficiency was optimized (117.3%) at the third harvest, and biological and economic yields increased by 36.7% and 36.4%, respectively. Lignin was the most degraded in C1t3, while residual cellulose, hemicellulose, neutral detergent fiber, and acid detergent fiber were higher in all treated substrates than in control. In C2t1, mushrooms were the richest in proteins, while in C1t1, they were the richest in the essential amino acids threonine, valine, isoleucine, leucine, and histidine. Lithovit®-Amino25 has a high potential for use in P. ostreatus production.

The work investigated the effect of Lithovit-Urea50 on the composition of Pleurotus ostreatus (Jacq. Ex Fr.) P. Kumm. (1871) cultivated on spent oyster substrate mixed with wheat straw (1:1, w/w mixture). The product was applied in different doses (C1: 3 g kg−1 and C2: 5 g kg−1) at three distinct timings (t1: at spawning, t2: after first harvest, t3: at spawning and after first harvest). Protein and fiber contents increased respectively by 0.64 and 0.2% in C1t1 and by 0.46 and 0.8% in C2t2 compared to control (C0t0). Total carbohydrates increased by 0.48–3.76%. Sucrose and glucose contents decreased in the majority of treatments, while fructose increased in C2t1 (by 0.045%). Essential amino acids were the highest in C1t1, wherein respective improvement of 0.31, 0.10, 0.05, 0.21, 0.18, and 0.09% compared to C0t0. Similarly, C1t1 was superior in non-essential amino acids. Potassium, sodium, calcium, iron, and copper contents decreased in all treatments, with minor exceptions, zinc decreased in C1t1 and C2t1, while nickel and lead increased in all treatments. Conclusively, despite important ameliorations in the mushroom nutritional value, mostly in C1t1, the product should be further tested in lower doses (< 3 g kg−1) to counteract its effect on heavy metal bioaccumulation.