Optimum conditions for inducing laccase production in Lentinus crinitus.

Laccases are environmentally friendly alternatives in many important applications such as in bioremediation, biopulping, textile, and the food industry. They have wide substrate specificity, can oxidize a broad range of compounds, and show potential for use in various industrial processes. Therefore, developing methods to increase laccase production is important. In the current study, we aimed to identify optimum conditions for inducing laccase production in the basidiomycete Lentinus crinitus cultivated under varying nitrogen concentrations and in the presence of potential inducers of laccase production, including copper and phenolic compounds. Peak enzymatic activity (11,977 U/L) occurred at higher nitrogen concentrations (2.8 g/L nitrogen). Regardless of the nitrogen concentration, addition of copper increased the laccase activity and decreased mycelial growth, with maximum laccase activity (14,320 U/L) observed at the highest nitrogen concentration combined with 150 mM CuSO4. In addition, ethanol (0.5 or 1.0 mM) and guaiacol (1.5 mM) increased laccase production to 15,000, 14,800, and 14,850 U/L, respectively. Our findings highlighted the optimum conditions for producing L. crinitusderived laccase as potential alternatives to the conventional production and application of the enzyme.

HS/GC-MS analyzed chemical composition of the aroma of fruiting bodies of two species of genus Lentinus (Higher Basidiomycetes).

The chemical composition of the aroma of fresh fruiting bodies of the cultivated mushroom Lentinus boryanus is described here and compared with medicinal shiitake mushroom L. edodes. Volatile compounds were analyzed through headspace sampling coupled with gas chromatography-mass spectrometry. The mushrooms under study were grown on different substrates based on barley straw, sugarcane bagasse, oak wood sawdust, and beech leaf litter. It was determined that L. boryanus as well as L. edodes contain an abundant amount of a volatile compound identified as 3-octanone with a sweet fruity aroma. On the other hand, only L. boryanus produced 3-octanol a characteristic aroma of cod liver oil. In total, 10 aromatic compounds were identified, some of which were obtained exclusively in one species or substrate.

Mycelial biomass and biochemical properties of proteases produced by Lentinus citrinus DPUA 1535 (Higher Basidiomycetes) in submerged cultivation.

The cultivation of Lentinus citrinus for mycelial biomass and protease production under different carbon and nitrogen sources was studied in submerged cultivation. The nutritional source concentration for protease production was evaluated using a full factorial design. For mycelial biomass maltose (4.94 mg/mL) and beef extract (5.45 mg/mL), carbon and nitrogen sources presented the best results, respectively. The maximum protease activity was 73.33 U/mL with fructose (30.0 g/L) and beef extract (10.0 g/L). Proteases showed maximum activity at 40°C and pH 7.0, which exhibited high stability at experimental conditions. The final part of this work was devoted to estimating the main thermodynamic parameters of the irreversible enzyme inactivation (ΔH* = 17.86 kJ/mol, ΔG* =102.09 kJ/mol, ΔS* = -260.76 J/mol×K) through residual activity tests carried out at 25-70°C, by making use of Arrhenius and Eyring plots.

The influence of different submerged cultivation conditions on mycelial biomass and protease production by Lentinus citrinus Walleyn et Rammeloo DPUA 1535 (Agaricomycetideae).

The influence of different carbon and nitrogen sources, pH of the culture medium, and temperature and period of cultivation on mycelial biomass production and protease activity by Lentinus citrinus DPUA 1535 were investigated in submerged culture. A 2(5) full factorial design with three central points was employed, and the results showed that at a significance level of 95% only nitrogen source and temperature were statistically significant for mycelial biomass production. On the other hand, for protease activity all factors and some interactions were significant, and the temperature and nitrogen source had the most significant effect. The best condition for mycelial biomass production (5.76 mg mL(-1)) and protease activity (32.3 U mL(-1)) was obtained in medium formulated with 0.5% soluble starch, 0.2% gelatin, pH 7.0, 25 degrees C, in 5 days.

Temperatura e meio de cultura mais favoráveis ao crescimento micelial de uma linhagem de Lentinus strigosus de ocorrência na Amazônia / Most favorable temperature and culture medium for the mycelial growth of a strain of Lentinus strigosus from the Amazon region

O objetivo do trabalho foi avaliar o crescimento micelial de uma linhagem de Lentinus strigosus, de ocorrência na Amazônia, em cinco meios de cultura à base de malte, serragem de marupá (Simarouba amara), serragem de pau de balsa (Ochroma piramidale), estipe de pupunheira (Bactris gasipaes Kunth) e bagaço de cana-de-açúcar (Saccharum officinarum), submetidos às temperaturas de 20, 25, 30, 35, 40, 45 e 50º C. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 5 x 7. Cada tratamento constou de quatro repetições, correspondente a uma placa de Petri, totalizando 140 unidades experimentais. Verificou-se que a temperatura de 35° C foi a mais favorável para o crescimento micelial de L. strigosus e que o meio à base de estipe de pupunheira foi o mais promissor para o cultivo deste fungo.

The objective of this work was to evaluate the mycelial growth of a strain of Lentinus strigosus occurring in the Amazon region in five culture mediums made on the basis of malt, "marupá" sawdust (Simarouba amara), "pau de balsa" sawdust (Ochroma piramidale), peach palm stipe (Bactris gasipaes Kunth) and crushed sugarcane (Saccharum officinarum), when submitted to different temperatures (20, 25, 30, 35, 40, 45 and 50º C). The experimental design was totally randomized, in a 5 x 7 factorial scheme. Each treatment corresponded to a Petri dish with four repetitions, totaling 140 experimental units. The temperature of 35º C was found to be the most favorable for the mycelial growth of L. strigosus, and the medium with peach palm stipe was the most promising for the cultivation of this fungus.

Optimal conditions for the fruit body production of natural occurring strains of Lentinus tigrinus.

Lentinus tigrinus is a species with a fleshy pileus, strong odor and agreeable taste. In order to determine the optimal conditions for the production of this species, three substrates based on Salix sp. sawdust, wheat straw and supplements were tested in 500g dry weight bags at two different fruiting temperatures. Naturally occurring strains of this species were incubated at 30 degrees C. Primordium initiation could be observed 11-16 days after induction conditions began. This species produced highest yields with biological efficiency (BE) of 62% with supplemented sawdust at 25 degrees C. When bags were reduced to 100g dry weight, spawning run time was reduced from 28 to 30 to 10 to 14 days and BE increased more than 100%. L. tigrinus is a promising species with possibilities for commercial production.

Solid state cultivation--an efficient method to use toxic agro-industrial residues.

Studies were carried out to screen twelve strains of Lentinus edodes for their efficiency to grow on toxic agro-industrial residues of coffee industry in solid state cultivation (SSC). Based on best mycelial growth (7.57 mm/day) and biomass production (48.78 mg/plate in 12 days at 24 degrees C) in coffee husk extract medium, a strain, L. edodes LPB 02 was selected for mushroom cultivation in SSC on coffee husk (treated and untreated), coffee spent ground, and a mixed-substrate comprising coffee husk and coffee spent ground (1:1). SSC was carried out under different conditions of moisture and spawn rate. Spawn rate of 10% and moisture level of 55-60% was found suitable for all the substrates. Treatment of the coffee husk with hot water was found useful for its utilization by the fungus. Results showed that there was an increase in the protein content and decrease in the fibre content of the substrates after SSC. Fruiting bodies were obtained from the treated coffee husk, spent ground and mixed-substrate, and the biological efficiency achieved was 85.8, 88.6 and 78.4% for these substrates, respectively. However, no fruiting body was obtained with raw coffee husk was used as the substrate. Results showed that after SSC, there was a decrease of about 27, 40 and 24% in caffeine and about 18, 49 and 12% in tannin contents in the treated coffee husk, coffee spent ground and mixed substrate, respectively. No caffeine or, tannins were found in fruiting body indicating their degradation by the fungal strain.