Enhanced yield of shiitake by saccharide amendment of the synthetic substrate

Novel Myco-Coagulant Produced by Lentinus squarrosulus for Removal of Water Turbidity: Fungal Identification and Flocculant Characterization

Several river water fungal strains (RWF-1 to RWF-6) were isolated to investigate the potential of having coagulant properties from the metabolites produced by the fungus. The myco-coagulant produced from the liquid-state process was characterized and tested for flocculation of kaolin water. Molecular identification of the fungal strain isolated from river water and characterization of the myco-coagulant produced by the strain are presented in this paper. The genomic DNA of the fungal 18S ribosomal ribonucleic-acid (rRNA) and 28S rRNA genes were used and the species was identified as Lentinus squarrosulus strain 7-4-2 RWF-5. The characterization of myco-coagulant by Fourier-transform infrared spectroscopy (FTIR) showed that hydroxyl, carbonyl, amide and amine groups as principal functional groups were present in the new myco-coagulant. The mean zeta potential value of the myco-coagulant was −7.0 mV while the kaolin solution was −25.2 mV. Chemical analyses of the extracellular myco-coagulant revealed that it contained total sugar (5.17 g/L), total carbohydrate (237 mg/L), protein (295.4 mg/L), glucosamine (1.152 mg/L); and exhibited cellulase activity (20 units/L) and laccase activity (6.22 units/L). Elemental analyses of C, H, O, N and S showed that the weight fractions of each element in the myco-coagulant was 40.9, 6.0, 49.8, 1.7 and 1.4%, respectively. The myco-coagulant showed 97% flocculation activity at a dose of 1.8 mg/L, indicating good flocculation performance compared to that of polyaluminum chloride (PAC). The present work revealed that the fungal strain, L. squarrosulus 7-4-2 RWF-5 is able to produce cationic bio-coagulant. The flocculation mechanism of the novel myco-coagulant was a combination of polymer bridging and charge neutralization.

Nutritional Composition, Antioxidant Activities, and Antiulcer Potential of Lentinus squarrosulus (Mont.) Mycelia Extract

Water extract of Lentinus squarrosulus mycelia was analysed for nutritional content, antioxidant capacity, and antiulcer ability. The extract contains high protein (57.6 g/100 g) and low total fat (0.5 g/100 g) and is rich in magnesium (0.4 g/100 g), potassium (3.8 g/100 g), vitamins B₁ (1.42 mg/100 g), and B₃ (194.29 mg/100 g) with total phenolic content of 39.16 mg/100 g. The cupric reducing antioxidant capacity and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of the extract were A₄₅₀ of 0.20 ± 0.03 at 0.5 mg/ml and IC₅₀ of 14.29 mg/ml, respectively. Oral feeding of L. squarrosulus extract (250 mg/kg) offered significant gastric mucosal protection of Sprague-Dawley rats compared to cimetidine (50 mg/kg). The ulcer healing rate of ulcerated rats after 24, 48, and 72 hours of treatment was 82%, 90%, and 100%, respectively. The IL-1β level in the serum and the NF-κB level in the tissues indicate that the healing potential was associated with attenuation of proinflammatory cytokines.

Evaluation of the yield of Lentinus squarrosulus (Mont) Singer on selected economic tree species

Sawdust from seven economic trees (Mansonia altissima, Piptadeniastrum africanum, Nesogordonia papaverifera, Combretodendron macrocarpum, Terminalia sp., Khaya ivorensis and Brachystegia nigerica were used to cultivate Lentinus squarrosulus (Mont) Singer. The highest mycelial density was observed in the sawdust of Mansonia altissimia and lowest in Piptadeniastrum africanum. Time of premodial emergence, fresh weight of mushroom and number of flushes varied from one sawdust to the other. The best sawdust for the growth of this mushroom among the sawdust of the economic trees was that of Combretodendron macrocarpum.

Effects of substrate moisture content, log weight and filter porosity on shiitake (Lentinula edodes) yield

Production costs for shiitake (Lentinula edodes) are on the rise in the United States due to increasing expenses including materials, labor and energy. Increased yield and improved bioconversion of raw materials may improve grower profit margins and may help reduce the cost of shiitake to the consumer. Two crops (Crop 1 and 2) of shiitake were grown to evaluate effects of three substrate moisture contents (50%, 55% and 60%), two log weights (2.7 and 3.2kg) and three porosities of bag filter (low, medium and high) on mushroom yield (g/log) and biological efficiency (BE). Yield data were collected under controlled environmental conditions for two breaks. The formulation with 55% substrate moisture gave the highest yield and BE. Higher mushroom yields were produced from heavier logs (3.2kg), but BE was not significantly affected. Filter porosity significantly affected yield and BE in Crop 1 but not in Crop 2. Significant interactions were observed for log moisture content x filter porosity for both crops. There were no significant two-way interactions observed for filter porosity x log weight or three-way interactions observed for moisture content x filter porosity x log weight. Maximum yields were obtained from 3.2kg logs with a substrate moisture content of ca. 55% using medium or low porosity-filtered bags. This study may provide growers with additional information to better optimize production practices and become more efficient and competitive.

Influence of precipitated calcium carbonate (CaCO3) on shiitake (Lentinula edodes) yield and mushroom size

Synthetic substrate consisting of oak sawdust (50%), white millet (28%), winter rye (11%) and soft red wheat bran (11%) was non-supplemented or supplemented with 0.2%, 0.4% or 0.6% (dry weight basis) precipitated calcium carbonate (CaCO(3)). Shiitake (Lentinula edodes) was grown in two crops to determine the effect of three CaCO(3) levels on mushroom yield and size. Yields and biological efficiencies (averages for two crops) from substrates non-supplemented with CaCO(3) were lower by 14.1%, 18.4% and 24.9% compared to treatments supplemented with 0.2%, 0.4% and 0.6% CaCO(3), respectively. Mushroom size (weight) was larger with non-supplemented substrate (16.8 g) compared to substrate supplemented with 0.6% CaCO(3) (15.1 g). However, mushroom production was more consistent from crop to crop when 0.6% CaCO(3) was added to substrate.

Influence of substrate wood-chip particle size on shiitake (Lentinula edodes) yield

Wood chips from four commercial hardwood sawmills were screened with 10 US standard sieves (4-0.21 mm) to assess particle size distributions. 96-98% of wood chips were < 4 mm while 95-99% of particles were > 0.21 mm. The majority (mean = 64.5%) of wood chips passed through US standard sieve size 14 (< 1.4 mm). Shiitake (Lentinula edodes) was grown in three crops to determine the effect of four particle size classes (1 = 2.8-4 mm; 2 = 1.7-2.8 mm; 3 = 0.85-1.7 mm; 4 = < 0.85 mm) on mushroom yield. Yields from substrates prepared with wood chips from class 4 (< 0.85 mm) were lower by 27.7%, 12.4% and 2% (mean = 14.9%) for Crops I, II, and III, respectively, when compared to controls. Profiling of wood chips may help growers optimize their production media and reduce production costs.