Mixing oak and eucalyptus sawdusts improves shiitake (Lentinula edodes) yield and nutritional value

The study aimed to explore suitable substrates comprising locally available hardwood sawdusts for the cultivation of Shiitake (Lentinula edodes) in Lebanon. Sawdusts of oak (OS), maple (MAP), and eucalyptus (EUC) were used alone or in combination, supplemented equally by wheat bran (WB). Results showed that complete mycelia run, fruiting, and harvest dates were the minimum in OS-WB: 800-200 by 72.2, 75.5, and 79.5 days after spawning (DAS) respectively, and the maximum in EUC-MAP-WB: 400-400-200 (by 88.3, 87.5, and 92.0 DAS, respectively). The substrate EUC-OS-WB: 400-400-200 had the highest biological efficiency (74.1%) compared to all treatments. Mushroom numbers ranged between 13.0 and 29.5 at harvest 1 (H1) and between 9.5 and 26.5 at harvest 2 (H2), showing a significant decrease in H2 in comparison to H1 in all treatments. Mushroom weight ranged between 8.8 and 25.9 at H1 and between 5.9 and 14.6 at H2. Furthermore, stepwise correlation showed that total biological yield (TBY) was positively affected by the biological yield at first harvest (BYH1) in OS-WB: 800-200 (R2 = 0.943), and at BYH2 in EUC-WB:800-200 (R2 = 0.944) and MAP-WB: 800-200 (R2 = 0.998), and it was negatively affected by BYH1 and stipe diameter in MAP-OS-WB: 400-400-200 (R2 = 0.946). Also, there was an improvement in mushroom protein, crude fibers, and vitamin C contents, and a decrease in carbohydrate contents on most substrates compared to control. Mushrooms obtained in EUC-OS-WB:400-400-200 recorded the highest protein and crude fiber contents (15.1 and 5.4%). Therefore, the mixture containing oak and eucalyptus sawdust has a good potential to improve shiitake yield and nutritional value compared to oak sawdust and could be an appropriate alternate for producing shiitake mushrooms.