Growth,fruiting and lignocellulolytic enzyme production by the edible mushroom <Emphasis Type="Italic">Grifola frondosa</Emphasis> (maitake)

Cultivation of specialty mushrooms on lignocellulosic wastes represents one of the most economical organic recycling processes. Compared with other cultivated mushrooms, very little is known about the nature of the lignocellulolytic enzymes produced by the edible and medicinal fungus Grifola frondosa, the parameters affecting their production, and enzyme activity profiles during different stages of the developmental cycle. In this work we investigated the enzymes that enable G. frondosa, to colonize and deconstruct two formulations based on industrial lignocellulosic by-products. G. frondosa degraded both substrates (oak-sawdust plus corn bran, and oak/corn bran supplemented with coffee spent-ground) decreasing 67 and 50% of their lignin content, along with 44 and 37% of the polysaccharides (hemicellulose and cellulose) respectively. 35.3% biological efficiency was obtained when using oak sawdust plus corn bran as substrate. Coffee spent-ground addition inhibited mushroom production, decreased growth, xylanase and cellulase activities. However, taking into account that G. frondosa successfully colonized this residue; this substrate formula might be considered for its growth and medicinal polysaccharide production. Although G. frondosa tested positive for Azure B plate degradation, a qualitative assay for lignin-peroxidase, attempts to detect this activity during solid state fermentation were unsuccessful. Enzyme activities peaked during colonization but declined drastically during fruiting body formation. Highest activities achieved were: endoglucanase 12.3, exoglucanase 16.2, β-glucosidase 2.3, endoxylanase 20.3, amylase 0.26, laccase 14.8 and Mn-peroxidase 7.4 U/g dry substrate.     

Effects of different nitrogen rich substrates and their combination to the yield performance of oyster mushroom (<Emphasis Type="Italic">Pleurotus ostreatus</Emphasis>)

This study was conducted to assess the effect of nitrogen (N) variations from lignocellulosic substrates of empty fruit bunch (EFB), palm oil frond (POF), palm oil trunks (POT), A.mangium bark (AB) and Cogongrass (IC), and combinations among them using biological supplements (POF and POT) for suitability as a substrate of P. ostreatus. Three different sets of substrates were evaluated in response to different parameters of P. ostreatus including spawn running, primordial initiation, fruit body yield and biological efficiency (BE). The supplementation of POT and POF generally revealed significant differences on the crop performance of P. ostreatus compared to the un-supplemented substrate. POT demonstrated reduced production time, while POF was the best supplement to promote fresh weight and BE. The most rapid spawn running took place within 18.6 ± 0.9 days, while the primordial initiation was observed within 23.2 ± 0.5 days in the combination of IC + POT. The most suitable substrate for higher mushroom weight and BE was IC + POF (19.6 ± 1.3 g; 70.5 ± 5.5%). In addition, the interval between primordial formations was found to be fastest in the un-supplemented EFB and the combination of EFB + POF, which supported a shortened production time. Therefore, IC and EFB appeared to be the better alternative materials for growing P. ostreatus, either with or without any supplementation.     

Modeling Grifola frondosa fungal growth during solid‐state fermentation

Grifola frondosa (maitake) is an edible and medicinal mushroom. Considering its increasing popularity, there are limited references for its cultivation. Previous studies demonstrated that carpophore formation is correlated directly with mycelial biomass. The development of a mathematical model for its growth under solid‐state fermentation (SSF) may help to predict the potential of different substrates for maitake production. G. frondosa growth and basidiome development was studied, using oak sawdust and corn bran as substrates. The fungal biomass content was determined by measuring N‐acetyl‐D ‐glucosamine (NAGA). It increased steadily for the first 80 days, to a maximum in coincidence with the first fruiting (60.5 μg NAGA/mg dry sample). Two mathematical models were selected to evaluate G. frondosa development, measuring reducing sugars consumption and NAGA synthesis, as an indirect assessment of fungal growth. Both models showed a good fit between predicted and experimental data: logistic model (R²=0.8896), two‐stage model (R²=0.8878), but the logistic model required a minor number of adjustment parameters.     

Recycling spent larval food of Corcyra cephalonica Stainton for preparing spawn and sporophore of Pleurotus sajor-caju (Fr.) Singer

Large scale production of the rice moth, Corcyra cephalonica Stainton in pearl millet grain medium leads to a huge accumulation of spent larval medium in commercial insectaries. We attempted bioconversion of spent larval medium of C. cephalonica (CLM) for cultivation of the mushroom Pleurotus sajor-caju (Fr.) Singer, to increase the usage of these residues. Maximum efficiency limits of CLM for spawn run, sporophore cropping and as bed substrate were assessed with varying combinations of sorghum and rice straw. Sorghum grains and rice straw were the best substrates for spawn run and sporophore yield respectively. Having been crushed, macerated, heated and sterilized, CLM could also become a suitable substrate along with sorghum or rice straw. Sorghum and CLM at 16.7% + 83.3% and 33.3% + 66.7% combinations were very effective in supporting mycelial growth and quicker colonization of fungus, and mother spawn yield. The spawn that was obtained from these combinations yielded higher sporophore as well. The fungus did not rapidly colonize on other combinations (50% + 50%, 66.7% + 33.3% and 83.3% + 16.7%), and was completely unable to grow on CLM 100%. Combination of rice straw and CLM at 75% + 25% and 50% + 50% as bed substrate contributed higher sporophore yield. Analysis of the substrates indicated variation in their chemical and mineral composition, but they were good sources of N, P and Ca. The prospects of exploring CLM for the mushroom cultivation are discussed.     

Cultivation of the Dible Mushroom Lentinula edodes (Shiitake) in Pasteurized Wheat Straw – Alternative Use of Georthermal Energy in Mexico

Five edible Lentinula edodes strains were evaluated. The mushrooms were cultivated on a wheat straw substrate that was previously pasteurized by immersion in water heated by residual geothermal vapor, which was also used to warm incubation and production rooms. Finely chopped wheat straw (Triticum aestivum L.) was pasteurized and then spawned with supplemented spawn capable of supplying nutrients and enriching the substrate, with the expectation of yield improvement. The samples were incubated for 60 days before the production started and thus, the mushrooms produced had pileus diameters ranging from 5 to 20 cm. The yields fluctuated from 6.2 to 13.9 % (fresh weight of mushrooms/fresh weight of substrate). Biological efficiency ranged from 24.8 to 55.6 % (fresh weight of mushrooms/dry weight of substrate), while the production rate reached varied from 0.19 to 0.55 % (biological efficiency/production time starting from inoculation). The cultivation system evaluated here offers the possibility of lowering production costs by cultivating the mushroom on easily obtainable substrate and shortening the culture cycle. The efficiency of this use of geothermal energy and supplemented spawn for shiitake mushroom cultivation on non‐sterilized substrates was proven.     

Abundance and distribution of <Emphasis Type="Italic">Microdispus lambi</Emphasis> (Acari: Microdispidae) in Spanish mushroom crops

The myceliophagous mite Microdispus lambi has become a veritable plague since 1996, when it was first observed in Spanish mushroom crops, and is now causing substantial economic losses, particulary in spring and summer. This study looks at seasonal variation of the pest, its distribution on commercial farms and the population development during the crop cycle of the common white mushroom, Agaricus bisporus. Over a period of 18 months, 24 consecutive mushroom crop cycles were monitored and a total of 24 spawn and 960 substrate samples were analysed. We found that it is usually the substrates in the growing rooms that are infested, most commonly the compost. In many cases, the pest can be detected when the first ‘flush’—i.e., mushroom growth surge, with weekly periodicity—is harvested, although damage does not become evident until the third flush. Mites were detected at the back of the mushroom growing room and, to a lesser extent, near the access door.     

Effects of nutrient supplements on biological efficiency, quality and crop cycle time of maitake (Grifola frondosa)

The effects of various combinations of wheat bran, rye and millet (at 20% and 30% of total dry substrate wt) on crop cycle time, biological efficiency (BE) and mushroom quality were evaluated for a commercially used isolate of Grifola frondosa (maitake). Supplements were combined with a basal ingredient of mixed oak (primarily red oak) sawdust, and the resulting mixture was pasteurized, cooled, inoculated and bagged with an autoclaving mixer. Times to mushroom primordial formation and mushroom harvest were recorded, and mushroom quality was rated on a scale of 1-4, where 1 was the highest quality and 4 was the lowest quality. The combinations of 10% wheat bran, 10% millet and 10% rye (BE 47.1%, quality 1.8 and crop cycle 12 weeks) and 10% wheat bran plus 20% rye (BE 44%, quality 1.7 and crop cycle 10 weeks) gave the most consistent yields and best basidiome quality over time.     

Evaluating the addition of activated carbon to heat-treated mushroom casing for grain-based and compost-based substrates

Two substrates, a non-composted grain spawn substrate and a traditional composted substrate, each covered with peat-based casing that contained varying amounts of activated carbon (AC) and each receiving different heat-treatment durations, were tested for Agaricus bisporus mushroom production. The amounts of AC were 0, 5, 10, 15, and 20% v/v, and the heat treatments were 0, 60, and 180 min at 121 °C and 103.4 kPa. Overall, the addition of AC up to 10–15% of casing for a grain spawn substrate increased mushroom yield. However, the addition of AC to the casing for compost substrates had no significant effect on yield, whereas heat-treating the casing increased yield. The onset of fruiting was retarded in grain spawn treatments not receiving AC with heat-treatment durations of 60 and 180 min, whereas this effect was not as apparent for the compost substrates. On average, mushroom yield was greater for the grain spawn substrate (366 g) than for compost substrate (287 g). For grain spawn substrate, the results show that the addition of AC ranging from 5% to 10% was adequate for maximum mushroom production.     

Comparative study on the growth and yield of<Emphasis Type="Italic"> Pleurotus ostreatus</Emphasis> mushroom on different lignocellulosic by-products

Eight lignocellulosic by-products were evaluated as substrates for cultivation of the oyster mushroom, Pleurotus ostreatus (Jacq. ex. fr) Kummer. The yields of mushroom on the different substrates were 183.1, 151.8, 111.5, 87.8, 49.5, 23.3, 13.0 and 0.0 g for composted sawdust of Triplochiton scleroxylon, rice straw, banana leaves, maize stover, corn husk, rice husk, fresh sawdust, and elephant grass, respectively. The biological efficiency (BE) followed the same pattern and ranged from 61.0% for composted sawdust to 0.0% for elephant grass. The yield of mushroom was positively correlated to cellulose (r ² =0.6), lignin (r ² =0.7) and fibre (r ² =0.7) contents of the substrates. Based on the yield and BE of the substrates tested, rice straw appeared to be the best alternate substrate for growing oyster mushrooms. Electronic Publication     

Tea waste as a supplement for the cultivation of <Emphasis Type="Italic">Ganoderma</Emphasis> <Emphasis Type="Italic">lucidum</Emphasis>

Tea waste (TW) was investigated as a new supplement for substrate mixtures in Ganoderma lucidum cultivation. The effects of sawdust (S) based substrates supplemented with TW at the various levels (75S:25TW, 80S:20TW, 85S:15TW, and 90S:10TW) and Ganoderma lucidum strains on yield, biological efficiency (BE) and the chemical composition of fruiting bodies were determined in solid-state fermentation. Significant differences were found among substrates regarding yield and BE, while yield and BE of the strains were not different. The substrate formulations producing highest yield and BE were 80S:20TW (87.98 g/kg substrate and 34.90%) and 75S:25TW (82.30 g/kg substrate and 31%). Yield and BE of substrates containing TW were generally higher than that of the control (80sawdust:18wheat bran:1sucrose:1 CaCO₃). Nitrogen, potassium, iron, and manganese contents and C:N ratios of substrates were strongly correlated with yield. BE showed positive and significant correlations with potassium, iron and manganese. Moisture content, potassium, magnesium, calcium, iron, and zinc contents of the fruiting bodies were affected by both strain and substrate. It was concluded that TW can be used as a supplement for substrate preparation in G. lucidum cultivation.     

Effect of Nutritional Parameters on Laccase Production by the Culinary and Medicinal Mushroom, <Emphasis Type="Italic">Grifola frondosa</Emphasis>

Extracellular laccase in cultures of Grifola frondosa grown in liquid culture on a defined medium was first detectable in the early/middle stages of primary growth, and enzyme activity continued to increase even after fungal biomass production had peaked. Laccase production was significantly increased by supplementing cultures with 100–500 μM Cu over the basal level (1.6 μM Cu) and peak levels observed at 300 μM Cu were 7-fold higher than in unsupplemented controls. Decreased laccase activity similar to levels detected in unsupplemented controls, as well as an adverse effect on fungal growth, occurred with further supplementation up to and including 0.9 mM Cu, but higher enzyme titres (2- to 16-fold compared with controls) were induced in cultures supplemented with 1–2 mM Cu²⁺. SDS-PAGE combined with activity staining revealed the presence of a single protein band (M _r 70 kDa) exhibiting laccase activity in control culture fluids, whereas an additional distinct laccase protein band (M _r 45 kDa) was observed in cultures supplemented with 1–2 mM Cu. Increased levels of extracellular laccase activity, and both laccase isozymes, were also detected in cultures of G. frondosa supplemented with ferulic, vanillic, veratric and 4-hydroxybenzoic acids, and 4-hydroxybenzaldehyde. Using 2,2′-azino-bis(ethylbenzothiazoline-6-sulfonate) (ABTS) as substrate, the optimal temperature and pH values for laccase activity were 65°C and pH 2.2, respectively, and the enzyme was relatively heat stable. In solid-state cultures of G. frondosa grown under conditions adopted for industrial-scale mushroom production, extracellular laccase levels increased during the substrate colonization phase, peaked when the substrate was fully colonized, and then decreased sharply during fruit body development.     

Use of various coffee industry residues for the cultivation of Pleurotus ostreatus in solid state fermentation

Studies were carried out to evaluate the feasibility of using coffee industry residues, viz. coffee husk, coffee leaves and spent coffee ground as substrates in solid state fermentation (SSF) to cultivate edible mushrooms Pleurotus. Eight strains of Pleurotus ostreatus and two strains of Pleurotus sajor‐caju were screened on a medium prepared from aqueous extract of coffee husk and agar. Based on best mycelial growth (9.68 mm/day) and biomass production (43.4 mg/plate in 9 days at 24°C), the strain P. ostreatus LPB 09 was selected for detailed studies. SSF was carried out using these substrates under different moisture conditions (45–75%) and spawn rates (2.5–25%). In general, although a 25% spawn rate appeared superior, the 10% spawn rate was recommended for all the three substrates in view of the process economics, as there was not any significant difference in the increase with 10 to 15%. The ideal moisture content for mycelial growth was 60–65% for coffee husk and spent coffee ground, and 60–70% for coffee leaves. The biological efficiency (BE), which is defined as the ratio of the weight of fresh fruiting bodies to the weight of dry substrate, multiplied by 100, and which indicates the fructification ability of the fungus for utilizing the substrate, was best with coffee husk. With coffee husk as the substrate, the first fructification occurred after 20 days of inoculation, and the biological efficiency reached about 97% after 60 days. When coffee leaves were used as the substrate, no fructification was observed even upon prolonged cultivation. With spent ground as the substrate, the first fructification occurred 23 days after inoculation and the biological efficiency reached about 90% in 50 days. There was a significant decrease in the caffeine and tannin contents (61 and 79%, respectively) of coffee husk after 60 days. It was remarkable to observe that caffeine was adsorbed onto the fruiting body (0.157%), indicating that it was not completely degraded by the fungal culture. However, no tannins were found in the fruiting body, indicating that the fungal strain was capable of degrading them. The results showed the feasibility of using coffee husk and spent coffee ground as substrates without any pre‐treatment for the cultivation of edible fungi in SSF, and provided one of the first steps towards an economical utilization of these otherwise unutilized or poorly utilized residues.     

Cultivation of oyster mushrooms on wheat straw and bagasse substrate amended with distillery effluent

Summary Molasses-based distilleries produce large quantities of dark coloured effluent, which is a major cause of environmental pollution. An experiment was conducted to investigate the efficacy of distillery effluent amendment for edible mushroom production. Three species of oyster mushroom, namely Pleurotus florida Eger (EM 1303), Pleurotus pulmonarius (Fries) Quelet (EM 1302) and Pleurotus sajor-caju (Fries) Singer (EM 1304) were grown on wheat straw (variety UP 2338) and bagasse amended with post-anaerobic distillery effluent, a high organic load wastewater with high biochemical oxygen demand and chemical oxygen demand. Three different levels of effluent treatment were applied to bagasse and wheat straw. Wheat straw was found to be the preferred substrate and showed better results than bagasse in all treatments with respect to yield, biological efficiency (BE) and dry matter loss. P. florida (EM 1303) and P. pulmonarius (EM 1302) gave significantly enhanced yield with increasing levels of effluent, with BE reaching highest at 238.6% for P. florida (EM 1303). Using bagasse as a substrate, P. sajor-caju (EM 1304) and P.␣pulmonarius (EM 1302) exhibited a decreasing trend as compared to control. However, the effect of effluent concentrations did not influence yield and BE significantly in case of bagasse. The dry matter loss of the substrate varied from 9.4% to 53.4% in wheat straw and 17.5% to 45.2% in bagasse respectively.     

Forest farming of shiitake mushrooms: Aspects of forced fruiting

Three outdoor shiitake (Lentinula edodes (Berk.) Pegler) cultivation experiments were established during 2002–2004 at the University of Missouri Horticulture and Agroforestry Research Center, in central Missouri. Over three complete years following a year of spawn run, we examined shiitake mushroom production in response to the temperature of forcing water, inoculum strain, substrate host species and physical orientation of the log during fruiting. Forcing compressed the period of most productive fruiting to the two years following spawn run. Further, chilled forcing water, 10–12 °C, significantly enhanced yield, particularly when ambient air temperatures were favorable for the selected mushroom strain. The temperature of water available for force-fruiting shiitake logs depends on geographic location (latitude) and source (i.e., farm pond vs. spring or well water). Prospective growers should be aware of this effect when designing their management and business plans.     

Production of Pleurotus ostreatus mushrooms on sugar cane agrowastes

The growth of different strains of Pleurotus spp. on sugar cane agrowastes was evaluated. Three hybrid strains with good production outcomes and yields exceeding 17% were selected. Strain 184 (P. ostreatus x P. pulmonarius) showed the best results. Three spawn materials (wheat grain, millet grain and milled corn cob) at different spawning levels were tested and a significant influence was found. The obtained results were best explained in terms of total nitrogen content of the initial mixture (spawn + substrate), suggesting a probable nitrogen limited growth of the mushroom on sugar cane residues. A 10% millet grain spawn was found to be a reasonable compromise. Productive responses decreased with an increase in bag's capacity (8–10–12 kg), even though the same diameter was maintained in order to avoid pronounced temperature profiles. Smaller bag's capacities (8–10 kg) were recommended. It was also shown that the utilization of water hyacinth (Eichhornia crassipes) mixed 50/50 with sugar cane residues as substrate caused a twofold increase of crop responses, confirming the advantages of this substrate supplementation. The obtained results identified sugar cane agrowastes as a feasible substrate for Pleurotus spp. production with yields and biological efficiencies comparable and to some extent better than others reported with conventional lignocellulosic residues such as cereal straw.     

Effect of nutritional parameters on laccase production by the culinary and medicinal mushroom, Grifola frondosa

Summary Extracellular laccase in cultures of Grifola frondosa grown in liquid culture on a defined medium was first detectable in the early/middle stages of primary growth, and enzyme activity continued to increase even after fungal biomass production had peaked. Laccase production was significantly increased by supplementing cultures with 100–500 (M Cu over the basal level (1.6 mM Cu) and peak levels observed at 300 mM Cu were ∼ ∼7-fold higher than in unsupplemented controls. Decreased laccase activity similar to levels detected in unsupplemented controls, as well as an adverse effect on fungal growth, occurred with further supplementation up to and including 0.9 mM Cu, but higher enzyme titres (2- to 16-fold compared with controls) were induced in cultures supplemented with 1–2 mM Cu²⁺. SDS-PAGE combined with activity staining revealed the presence of a single protein band (M _r ∼ ∼70 kDa) exhibiting laccase activity in control culture fluids, whereas an additional distinct second laccase protein band (M _r␣∼ ∼45 kDa) was observed in cultures supplemented with 1–2 mM Cu. Increased levels of extracellular laccase activity, and both laccase isozymes, were also detected in cultures of G. frondosa supplemented with ferulic, vanillic, veratric and 4-hydroxybenzoic acids, and 4-hydroxybenzaldehyde. The optimal temperature and pH values for laccase activity were 65 °C and pH 2.2 (using 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonate) {ABTS} as substrate), respectively, and the enzyme was relatively heat stable. In solid-state cultures of G. frondosa grown under conditions adopted for industrial-scale mushroom production, extracellular laccase levels increased during the substrate colonization phase, peaked when the substrate was fully colonized, and then decreased sharply during fruit body development.     

<Emphasis Type="Italic">Polyporus tenuiculus</Emphasis>: a new naturally occurring mushroom that can be industrially cultivated on agricultural waste

Polyporus tenuiculus is a naturally occurring species from Central and South America that is consumed by different ethnic groups in the region. To determine the optimal conditions for fruiting body production, two strains were assayed on wheat straw and sawdust with or without supplements. Sixty days of incubation at 25°C were needed to produce a solid block. The highest yield was obtained with strain ICFC 383/00 grown on supplemented willow sawdust. In a second experiment the strain ICFC 383/00 and different supplements were used to improve the biological efficiency (BE) and to determine the quality traits and its biodegradation capacity. The highest yields were obtained on sawdust with 25% of supplements reaching 82.7% of BE. Supplements raised the number of flushes, generally from four to five, contributing to increased yields. The type of substrate had a significant effect on fruiting body diameters of P. tenuiculus, and the largest mushrooms were harvested on supplemented substrate with the highest BE coinciding with the highest dry matter loss in substrates. P. tenuiculus showed a capacity to degrade sawdust, causing a decrease of 67.2–74.5% in cellulose, 80.4–85.7% in hemicellulose, and 60.6–66.2% in lignin content at the end of the cultivation cycle. The decrease in hemicellulose was relatively greater than that of cellulose and lignin on supplemented substrates. This is the first report of the cultivation of P. tenuiculus on lignocellulosic waste, and it is a promising species both for commercial production and for its potential use in the degradation of other biowastes.     

Behavioural response of the fungus gnat,Bradysia impatiens (Diptera: Sciaridae) towards certain edible mushrooms and saprophytic fungi

The fungus gnat Bradysia impatiens (Johannsen) is a worldwide pest inhabiting organic-rich environments, including mushroom-cultivation substrates, which leads to massive production losses of edible mushrooms. To promote a non-insecticidal pest control strategy, we evaluated adult behavioural response towards two saprophytic fungal strains Aspergillus flavus Link and Mucor circinelloides Tiegh., isolated from B. impatiens-inhabiting substrates and six edible mushrooms species. Our results indicated that (a) B. impatiens was most attracted to the oyster mushroom Pleurotus ostreatus among all six edible mushrooms; (b) males and females demonstrated a significant attraction for M. circinelloides over A. flavus and P. ostreatus; (c) adults demonstrated dynamic attraction tendencies that varied with the culture periods of A. flavus and M. circinelloides, wherein females represented most (mean = 78.6%) of the attracted individuals; and (d) larvae that fed on mycelial cultures of M. circinelloides could complete their entire life cycles, but larvae could not survive on a non-fungal or A. flavus diet. These results demonstrate the potential for the development of M. circinelloides in a push-pull strategy to biocontrol this pest in edible mushroom cultivation.     

Comparative study on the mycelial growth and yield of Ganoderma lucidum (Curt.: Fr.) Karst. on different lignocellulosic wastes

The aim of this study was to examine the possibility of using wheat straw (WS), cottonseed meal (CSM), sunflower meal (SFM), soybean straw (SBS) and bean straw (BS) as basal substrates in Ganoderma lucidum cultivation instead of oak (OS) and poplar (PS) sawdusts. In the study, effects of different growing substrates on spawn running period, yield and biological efficiency (BE) of G. lucidum were determined. Moreover, possible correlations among productivity and lignocellulosic content of substrates were assessed. Average spawn run period varied between 14.2 and 18.2 d. Total yields of G. lucidum grown on different substrates ranged from 28.6 g/kg to 86.1 g/kg, while the corresponding values for BE varied between 8.9%–24.7%. The highest yield and BE was exhibited by the OS followed by PS substrate. CSM gave the lowest yield and BE. Spawn running time was found to be positively correlated to nitrogen content of the substrates (r² = 0.918) and negatively correlated to cellulose and hemicellulose content of substrate (r² = −0.927 and r² = −0.838, respectively). The total mushroom yield was correlated negatively to nitrogen content of the substrates (r² = −0.850) and positively correlated to C:N ratio (r²=0.915). Moreover, there is a strong positive correlation between mushroom yield and cellulose and lignin content of the substrates (r² = 0.794 and r²= 0.879). According to results, G. lucidum had a preference for substrates containing a high amount of cellulose and and lignin, and having a low amount of N and high cellulose:lignin ratio. Furthermore, SBS, WS and BS may be suggested as alternative basal substrates for cultivation of G. lucidum.     

Do spawn storage conditions influence the colonization capacity of a wheat-straw-based substrate by Agaricus subrufescens?

Storage conditions of the spawn of edible fungi are of major importance to facilitate the production of mushrooms. Here, standard storage conditions at 10 °C or 15 °C were used and the potential of colonization of standard European compost by the tropical species Agaricus subrufescens was assessed during the spawn running phase. Two lignocellulolytic activities, laccase and CMC-cellulase, were enhanced after storage compared to control as well as substrate transformation, as described by the aromaticity ratio and a humification ratio calculated from NMR data. This result indicates that mycelium growth probably occurred during storage at 10 or 15 °C, leading to a larger amount of biomass in the inoculum. Moreover, the microbial functional diversity of the substrate was favored, showing that the electivity of the substrate was maintained. Thus, these findings indicate that recommendations for the mushroom producers can be established for A. subrufescens cultivation under European standard conditions.