Compositional changes in lignocellulosic content of some agro-wastes during the production cycle of shiitake mushroom

Abstract

The study assessed the changes in digestibility of some agricultural wastes such as chickpea straw (CPS), corn stalk (CS), alfalfa hay (AH) and sunflower head residue (SFH) during the spawn running period and fruitbody production of Lentinula edodes (Berk.) Pegler (shiitake) to better understand the nutritional needs of this mushroom species. In addition, the effects of these wastes on some productivity features of shiitake cultivated under laboratory conditions were evaluated. Oak awdust (OS) was used as a control substrate. The substrates were analyzed for nitrogen (N), cellulose, hemicellulose and lignin content at three different growth stages. Morever, the effect of agro-wastes on spawn run time, time to first primordia initiation, time to first harvest, yield, biological efficiency (BE) and average mushroom weight were evaluated during the cultivation cycle. Among the five substrates, the SFH exhibited maximum productivity, followed by CPS (233.7 g/kg and 228.1 g/kg, respectively). No correlation was found between the shiitake yield and the N or lignocellulosic content of the growing substrates. On the other hand, the shiitake consumed hemicellulose during the spawn running period, whereas the consumption of cellulose and lignin occured during the pinheading and fruiting formation stages. The hemicellulose, cellulose and lignin contents in the spent substrate were 36.5–51.9%, 5.3–27.0% and 24.0–36.8% lower, respectively, than in the initial substrates, while the N content in the mushroom substrate was increased by 10.3% (CS)−97.1% (OS) after shiitake cultivation. In conclusion, shiitake mushrooms had a preference for substrates containing a moderate amount of N, hemicellulose and lignin, and having a low cellulose:lignin ratio. Morever, the chemical composition of the growing substrates changed during the life cycle of the mushroom and the protein content increased with time, while the amount of lignocellulosic content in the substrates was reduced, making it more digestible.