Effect of common foods as supplements for the mycelium growth of Ganoderma lucidum and Pleurotus ostreatus on solid substrates

The transition from a linear to a circular economy is urgently needed to mitigate environmental impacts and loss of biodiversity. Among the many potential solutions, the development of entirely natural-based materials derived from waste is promising. One such material is mycelium-bound composites obtained from the growth of fungi onto solid lignocellulosic substrates, which find applications such as insulating foams, textiles, packaging, etc. During growth, the fungus degrades and digests the substrate to create a web-like stiff network called mycelium. The development of the mycelium is influenced by several factors, including the substrate composition. As food waste accounts for nearly 44% of total municipal solid waste, incorporating food in the substrate composition could be a means to increase the nutrients absorbed by the fungus. In this paper, we study the effects of the addition of food supplements on the growth of two fungal species, Ganoderma lucidum and Pleurotus ostreatus. The substrates, the food supplements, and the mycelia are characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and optical microscopy. Our results show that addition of barley as a supplement significantly boosts the growth of G. lucidum and P. ostreatus. Using a common food as a nutritious enrichment for the development of mycelium is a simple and straightforward strategy to create waste-based mycelium-bound biocomposites for a large range of applications, on-site, therefore promoting a circular economy.

Combined effect of olive pruning residues and spent coffee grounds on Pleurotus ostreatus production, composition, and nutritional value

No previous study assessed the combined effect of olive pruning residues (OLPR) and spent coffee grounds (SCG) on P. ostreatus production and nutritional value. The aim of this study was to determine the capacity of P. ostreatus to degrade lignocellulosic nature of combined OLPR and SCG as well as their resultant nutrient composition. A complete randomized design was adopted with five treatments: S1:100%wheat straw (WS) (control), S2:33%WS+33%SCG+33%OLPR,S3:66%WS+17%SCG+17%OLPR,S4:17%WS+66%SCG+17%OLPR, and S5:17%WS+17%SCG+66%OLPR, and ten replicates per treatment. Substrate's and mushroom's composition were analyzed on chemical scale, including fatty acids and heavy metals profiles, following international standards. Only S1, S2, and S3 were productive, with comparable biological yield, economical yield, and biological efficiency. Organic matter loss decreased with increasing proportions of OLPR and SCG. Percentage lignin loss was higher in S1 than in S2 and S3 (53.51, 26.25, and 46.15% respectively). Mushrooms of S3 had some enhanced nutritional attributes compared to control: decrease in fat, increase in protein, increase in monounsaturated fatty acids, and lower zinc accumulation. Lead was less accumulated in S2 than S1 mushrooms. Sodium content of mushroom decreased in S2 and S3. The latter substrates yielded mushrooms with lower polyunsaturated fatty acids (PUFA) and higher saturated fatty acids (SFA) contents. All mushrooms had a valuable PUFA/SFA. This study suggests using OLPR and SCG in low proportions as nutritional supplements to the commercial wheat straw.

Would it be possible to use nonpathogenic fungi to improve the turnover of crop residues?

This study was aimed to assess the suitability of four fungal species for operating in the residues of three crops in Golestan province, Iran. For this, four experiments were conducted to analyze their ability to grow on five culture media (Experiment I) and on the residues (Experiment II) and their growth responses to different pHs (Experiment III) and temperature levels (Experiment IV). Then, the possibility of establishing these fungi in the cultivated lands of studied crops was examined. Fungal growth was high on soybean and cotton residues and low on those of rice, and all the fungi produced a significant reduction in the carbon to nitrogen ratios in relation to noninoculated residues. The amount of nitrogen in fungal-treated cotton residues increased about four times compared with the control and in other studied residues increased twice as much as the control. The lowest C:N values for cotton and rice residues were found for Pleurotus ostreatus while Aspergillus niger was the most efficient for those of soybean. The results also showed that these fungi will not show the best performance in respect to temperature and pH, but will not be ineffective. The results could be the basis for further studies on the use of these fungi to improve nutrient cycling, focusing on multicriteria zoning on climatic and soil-related components.

Advanced mycelium materials as potential self-growing biomedical scaffolds

Mycelia, the vegetative part of fungi, are emerging as the avant-garde generation of natural, sustainable, and biodegradable materials for a wide range of applications. They are constituted of a self-growing and interconnected fibrous network of elongated cells, and their chemical and physical properties can be adjusted depending on the conditions of growth and the substrate they are fed upon. So far, only extracts and derivatives from mycelia have been evaluated and tested for biomedical applications. In this study, the entire fibrous structures of mycelia of the edible fungi Pleurotus ostreatus and Ganoderma lucidum are presented as self-growing bio-composites that mimic the extracellular matrix of human body tissues, ideal as tissue engineering bio-scaffolds. To this purpose, the two mycelial strains are inactivated by autoclaving after growth, and their morphology, cell wall chemical composition, and hydrodynamical and mechanical features are studied. Finally, their biocompatibility and direct interaction with primary human dermal fibroblasts are investigated. The findings demonstrate the potentiality of mycelia as all-natural and low-cost bio-scaffolds, alternative to the tissue engineering systems currently in place.

Characterization of a Novel Laccase LAC-Yang1 from White-Rot Fungus Pleurotus ostreatus Strain Yang1 with a Strong Ability to Degrade and Detoxify Chlorophenols

In this study, a laccase LAC-Yang1 was successfully purified from a white-rot fungus strain Pleurotus ostreatus strain yang1 with high laccase activity. The enzymatic properties of LAC-Yang1 and its ability to degrade and detoxify chlorophenols such as 2,6-dichlorophenol and 2,3,6-trichlorophenol were systematically studied. LAC-Yang1 showed a strong tolerance to extremely acidic conditions and strong stability under strong alkaline conditions (pH 9–12). LAC-Yang1 also exhibited a strong tolerance to different inhibitors (EDTA, SDS), metal ions (Mn²⁺, Cu²⁺, Mg²⁺, Na⁺, K⁺, Zn²⁺, Al³⁺, Co²⁺, and metal ion mixtures), and organic solvents (glycerol, propylene glycol). LAC-Yang1 showed good stability in the presence of Mg²⁺, Mn²⁺, glycerol, and ethylene glycol. Our results reveal the strong degradation ability of this laccase for high concentrations of chlorophenols (especially 2,6-dichlorophenol) and chlorophenol mixtures (2,6-dichlorophenol + 2,3,6-trichlorophenol). LAC-Yang1 displayed a strong tolerance toward a variety of metal ions (Na²⁺, Zn²⁺, Mn²⁺, Mg²⁺, K⁺ and metal ion mixtures) and organic solvents (glycerol, ethylene glycol) in its degradation of 2,6-dichlorophenol and 2,3,6-trichlorophenol. The phytotoxicity of 2,6-dichlorophenol treated by LAC-Yang1 was significantly reduced or eliminated. LAC-Yang1 demonstrated a good detoxification effect on 2,6-dichlorophenol while degrading this compound. In conclusion, LAC-Yang1 purified from Pleurotus ostreatus has great application value and potential in environmental biotechnology, especially the efficient degradation and detoxification of chlorophenols.

The remediation of sulfonamides from the environment by Pleurotus eryngii mycelium. Efficiency, products and mechanisms of mycodegradation

The objective of the study was to assess the applicability of the mycelium obtained from the in vitro cultures of nontoxic bracket fungus, Pleurotus eryngii, to sulfonamides mycodegradation. Samples containing one of the six selected sulfonamides, sulfanilamide derivatives, were incubated with the mycelium of P. eryngii for 7 and 14 days in vitro. Subsequently, change in the sulfonamide concentration was assessed in the samples using the UPLC-QTof. The transformation products were identified based on monoisotopic molecular mass and fragmentation spectra. The studied sulfonamides did not inhibit the growth of P. eryngii mycelium in the in vitro cultures. In addition, a considerable reduction of sulfonamide concentration was observed in all the incubated samples (from 73.7 ± 8.3% to 99.8 ± 0.3%). In the case of three sulfonamides, the reduction in concentration >90% occurred after 7 days of incubation. However, the transformation of sulfonamides was partially caused by their degradation to simpler organic compounds. After incubation, the products of condensation of sulfonamides with formyl, acyl, and sugar groups, and amino acid-derived compounds were identified in the samples. This indicated the partially reversible nature of the mycodegradation process.

Effect of cultivating Pleurotus ostreatus on substrates supplemented with herb residues on yield characteristics, substrates degradation, and fruiting bodies' properties

BACKGROUND

Inappropriate disposal of herb residues in China has caused major problems for the immediate environment and to human safety. Here, three herb residues, compound Kushen injection (CKI), Qizhi Tongluo capsule (QTC), and Shenbai Shuxin capsule (SSC), were applied as substrates to corncob at various ratios (30:60, 45:45, and 60:30) for the propagation of the mushroom Pleurotus ostreatus. The effects of supplementation using herb residues on yield, biodegradation ability, bioactive compounds, antioxidant properties, and safety of P. ostreatus were assessed.

RESULTS

Different spawn running times were observed using growth medium, whereas 45CKI, 60QTC, and 30SSC media were determined as optimal-performing substrate combinations, resulting in yields of 843 g kg^-1 , 828 g kg^-1 , and 715 g kg^-1 respectively. Biodegradation analysis of consumed substrates revealed a significant decrease in cellulose and hemicellulose levels compared with lignin. Furthermore, chemical analysis of fruiting bodies revealed that the 45CKI and 60QTC substrates resulted in higher total phenol, flavonoid, terpenoid, and vitamin C levels, but significantly reduced water-soluble polysaccharides compared with the corncob medium. The methanol extract of fruiting bodies grown on substrates containing herb residues exhibited higher antioxidant properties than the control, as it was more effective in scavenging 2,2-diphenyl-1-picrylhydrazyl radicals, had greater reducing power, and more strongly inhibiting lipid peroxidation. Furthermore, high-performance liquid chromatography studies indicated that fruiting bodies did not generate matrine (a specific toxin produced in Kushen) when cultivated using the CKI substrate.

CONCLUSIONS

P. ostreatus cultivation on substrates mixed with herb residues facilitates herb residue management as well as bioactivity-rich and non-toxic fruit body formation. © 2020 Society of Chemical Industry.

Free Amino Acids in Three Pleurotus Species Cultivated on Agricultural and Agro-Industrial By-Products

Previous studies have demonstrated the feasibility of employing by-products of the olive and wine sectors for the production of Pleurotus mushrooms with enhanced functionalities. In this work we investigated the influence of endogenous and exogenous factors on free amino acids (FAAs) profile of Pleurotus ostreatus, P. eryngii and P. nebrodensis mushrooms produced on wheat straw (WS), alone or mixed with grape marc (GM), and on by-products of the olive industry (OL). Overall, 22 FAAs were determined in substrates and mushrooms, including all the essential amino acids, the neurotransmitter γ-aminobutyric acid (GABA) and ornithine. On a dry weight (dw) basis, total FAAs ranged from 17.37 mg/g in P. nebrodensis to 130.12 mg/g in P. ostreatus samples, with alanine, leucine, glutamine, valine and serine predominating. Similar distribution patterns were followed by the monosodium glutamate (MSG)-like, sweet and bitter FAAs. Significant differences in FAAs level were observed among the species examined and among the cultivation substrates used. Principal Component Analysis (PCA) performed on the entire FAAs profile of six Pleurotus strains, clearly separated P. ostreatus from P. eryngii and P. nebrodensis, in accordance to their phylogenetic affinity. This is the first report of FAAs in P. nebrodensis.

Effect of Different Culture Media, Grain Sources and Alternate Substrates on the Mycelial Growth of <i>Pleurotus eryngii</i> and <i>Pleurotus ostreatus</i>

BACKGROUND AND OBJECTIVE

Oyster mushroom Pleurotus is one of the most aromatic edible mushrooms. This study evaluated a few selected determinants for promoting mycelial growth and spawn production of P. eryngii and P. ostreatus such as culture media, grain sources and alternate substrates.

MATERIALS AND METHODS

Seven different substrate formulations were evaluated, viz: TS1 (100% wheat straw-S), TS2 (100% cardboard-C), TS3 (100% spent coffee ground-SCG), TS4 (50% S+50% C), TS5 (50% S+50% SCG), TS6 (80% S+20% C) and TS7 (80% S+20% SCG). The efficiency of different culture media potato dextrose agar (PDA), yeast malt agar ( YMA) and malt extract agar (MEA) and selected grains (wheat, rye, barley and oat) was investigated. Each study was arranged in the complete randomized design with 4 replicates.

RESULTS

PDA media was the most suitable for mycelial growth of P. eryngii while P. ostreatus had a better mycelial growth on YMA and MEA media. Barley and rye grains were the most favourable for the mycelium growth of P. eryngii while oat grains were the best source that enhanced both of mycelial extension and density levels of P. ostreatus. The supplement of wheat straw (S) with SCG substrate improved mycelial extension while the substrate containing 50% S+50% C was the most favourable for both of mycelial growth and primordia formation in P. eryngii and P. ostreatus.

CONCLUSION

The results revealed the feasibility of using recyclable wastes of cardboards and spent coffee ground for Pleurotus mushrooms cultivation. This would alleviate accumulation of urban generated wastes thus protecting the environment.

Comparative Proteomic Analysis of Pleurotus ostreatus Reveals Great Metabolic Differences in the Cap and Stipe Development and the Potential Role of Ca2+ in the Primordium Differentiation

Pleurotus ostreatus is a widely cultivated edible fungus around the world. At present, studies on the developmental process of the fruiting body are limited. In our study, we compared the differentially expressed proteins (DEPs) in the stipe and cap of the fruiting body by high-throughput proteomics. GO and pathway analysis revealed the great differences in the metabolic levels, including sucrose and starch metabolism, and sphingolipid signaling and metabolism, and the differences of 16 important DEPs were validated further by qPCR analysis in expression level. In order to control the cap and stipe development, several chemical inducers were applied to the primordium of the fruiting body according to the pathway enrichment results. We found that CaCl₂ can affect the primordium differentiation through inhibiting the stipe development. EGTA (ethyleneglycol bis (β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid) treatment confirmed the inhibitory role of Ca²⁺ in the stipe development. Our study not only shows great metabolic differences during the cap and stipe development but also reveals the underlying mechanism directing the primordium differentiation in the early development of the fruiting body for the first time. Most importantly, we provide a reliable application strategy for the cultivation and improvement of the Pleurotus ostreatus, which can be an example and reference for a more edible fungus.

Modulation of agronomic and nutritional response of Pleurotus eryngii strains by utilizing glycine betaine enriched cotton waste

BACKGROUND

This study aimed to evaluate the possibility of cotton waste enrichment with glycine betaine (GB) for production of two strains (P9, P10) of king oyster (Pleurotus eryngii). Cotton waste was used as (100%) control (T0 = cotton waste) and augmented with various combinations of GB, (T1 = 2 mmol L^-1 , T2 = 4 mmol L^-1 , T3 = 6 mmol L^-1 , T4 = 8 mmol L^-1 and T5 = 10 mmol L^-1 ). The response of king oyster to GB was evaluated by earliness, yield, biological efficiency (BE), minerals (nitrogen, phosphorus, potassium, zinc (Zn), copper (Cu), magnesium (Mg), manganese (Mn), iron (Fe), sodium (Na), calcium (Ca)), total sugars, total soluble solids, reducing sugars, non-reducing sugars, ascorbic acid, proximate (crude protein, carbohydrates, crude fibers, ash, fats) content of fruiting body and Fourier-transform infrared (FTIR) spectroscopy analysis compared with the control substrate (cotton waste).

RESULTS

The earliness, yield, and BE were higher as compared to control substrate and increased with an augmentation in the concentration of GB within the cotton waste. Two strains showed (on dry weight basis) 33.9-54.9 mg g^-1 nitrogen, 6.8-12.5 mg g^-1 phosphorus, 16.9-25.1 mg g^-1 potassium, 40.5-64.2 mg kg^-1 Zn, 17.1-37.3 mg kg^-1 Cu, 1174-1325 mg kg^-1 Mg, 20.1-29.1 mg kg^-1 Mn, 129-265 mg kg^-1 Fe, 779-835 mg kg^-1 Ca), 6.3%-11.3% total sugars, 7.3-14.9 °Brix total soluble solids, 2.1-7.3% reducing sugars, 10.4-18.1% crude protein, 3.6-4.4% crude fiber and 5.6-16.7 mg (100 g)^-1 on various concentration of GB enrich cotton waste. Cotton waste enriched with GB significantly affected nutritional profile of king oyster mushroom.

CONCLUSION

The results revealed that GB enriched cotton waste can be used as an innovative substrate to enhance the yield and quality of king oyster mushroom. © 2019 Society of Chemical Industry.

Combined fungal and photo-oxidative Fenton processes for the treatment of wood-laminate industrial waste effluent

The present study reports on the remediation of an effluent from the wood-laminate industry using Pleurotus ostreatus EB 016 in combination with photo-Fenton oxidation. Fermentation of the effluent with P. ostreatus EB-016 was carried out in agitated flasks to evaluate the influence of pH, and concentrations of carbon and nitrogen sources by a multivariate approach. Subsequently, bioassays was conducted in an air-lift bioreactor using the pre-optimized conditions. In addition, photo-Fenton oxidative treatment was employed to degrade recalcitrant compounds, and the ecotoxicity of the effluents were evaluated using Escherichia coli as a biological model. The crude effluent presented high contents of total phenolics (1,220 mg/L), solids (18.45 g/L) and color intensity (8,333 CU), besides high values of chemical (COD 2,477 mg O_2./L) and biochemical (BOD₅, 8,450 mg O₂/L) oxygen demand. Another feature was the high inhibition on Escherichia coli (71%). Reduction of 64% COD was obtained under optimized conditions (pH5.7, 7.5 g/L sucrose, 4.0 g/L ammonium nitrate) in agitated flasks after 10 days treatment. In the air-lift reactor, 50.6% COD and 29.9% total phenols were removed after 10 days. Combination of biotreatment with photo-Fenton oxidation resulted in removal of 99.2% COD and 92.2% phenolics and absence of inhibition on Escherichia coli.

Comparative transcriptomic analysis reveals molecular processes involved in pileus morphogenesis in Pleurotus eryngii under different light conditions

Light plays an important role in pileus differentiation in Pleurotus eryngii cultivation, and pileus morphology is influenced by light quality. To understand the effects of light quality on pileus morphology at the transcriptional level, we performed a comparative transcriptomic analysis of pilei grown under blue and red light irradiation. We identified 3959 differentially expressed genes (DEGs) between the blue and red light-treated pilei, which included 1664 up-regulated and 2295 down-regulated genes. These DEGs were significantly associated with light sensing, signal transduction, cell wall degradation and melanogenesis, suggesting that these processes are involved in pileus morphogenesis. Multiple DEGs related to respiratory functions were differentially expressed, suggesting that respiratory activity increased during pileus development regardless of light quality. These results provide a valuable view of the transcriptional changes and molecular processes involved in pileus morphogenesis under different light conditions and provide a foundation for yield improvement and quality control of P. eryngii.

Mapping the Secretome and Its N-Linked Glycosylation of Pleurotus eryngii and Pleurotus ostreatus Grown on Hemp Stalks

Our previous research showed that Pleurotus eryngii and Pleurotus ostreatus were effective fungi for pretreatment of industrial hemp stalks to improve enzymatic saccharification. The secretomes of these two fungi were analyzed to search for the effective enzyme cocktails degrading hemp lignin during the pretreatment process. In total, 169 and 155 proteins were identified in Pleurotus eryngii and Pleurotus ostreatus, respectively, and 50% of the proteins involved in lignocellulose degradation were CAZymes. Because most of the extracellular proteins secreted by fungi are glycosylated proteins, the N-linked glycosylation of enzymes could be mapped. In total, 27 and 24 N-glycosylated peptides were detected in Pleurotus eryngii and Pleurotus ostreatus secretomes, respectively. N-Glycosylated peptides of laccase, GH92, exoglucanase, phenol oxidase, α-galactosidase, carboxylic ester hydrolase, and pectin lyase were identified. Deglycosylation could decrease enzymatic saccharification of hemp stalks. The activities of laccase, α-galactosidase, and phenol oxidase and the thermal stability of laccase were reduced after deglycosylation.

Rare earth elements concentration in mushroom cultivation substrates affects the production process and fruit-bodies content of Pleurotus ostreatus and Cyclocybe cylindracea

BACKGROUND

Concentrations of 16 rare earth elements (REEs) and two actinides were determined for the first time both in cultivated mushrooms and in their production substrates by inductively coupled plasma mass spectroscopy. Moreover, the effect of REEs on cultivation parameters and composition of the final product was assessed, together with their potential use for authentication purposes.

RESULTS

The concentrations of REEs varied greatly among seven cultivation substrates and correlated with measurements in Cyclocybe cylindracea mushrooms; no such correlation was established in Pleurotus ostreatus. Reduction of hemicellulose, cellulose, and lignin in substrates during P. ostreatus cultivation was positively correlated with REE concentrations, which also affected the production performance depending on the species examined. In all cases, a negative correlation was established between bioconcentration factors (BCF) in mushrooms and REE content in substrates, while the effect of substrate composition on BCF values varied according to the element studied. The estimated daily intake values of REEs through mushroom consumption was at much lower levels than those reported as potentially harmful for human health.

CONCLUSION

The content of REEs in cultivation substrates and in mushrooms revealed that the bioaccumulation of elements differed in each fungus. The nature/origin of substrates seemed to affect the concentration of REEs in mushrooms to a considerable extent. © 2018 Society of Chemical Industry.

Effects of Adding Chicken Blood Meal and Fishmeal to Sludge Biogas as White Oyster Mushroom Media

BACKGROUND AND OBJECTIVE

The biogas sludge is generally not used optimally and people even pour it directly into the river that it cause environmental pollution. One of the ways to get the benefit from sludge and chicken blood meal or fishmeal is to use it as a substitute for bran in mushroom media. This study aimed to improve the nutrient content of biogas sludge with the addition of chicken blood meal (CBM) and fishmeal (FM) as substitute material for bran in white oyster mushroom media.

MATERIALS AND METHODS

The biogas sludge was dried in the sun for 3 days until its form resembled the soil. The treatment consisted of dried biogas sludge without CBM (BP0), dried biogas sludge with 1% CBM (BP1) and dried biogas sludge with 3% CBM (BP2). Each was added to the media of white oyster mushroom as much as 15% as substitute material for bran. The other treatment consisted of dried biogas sludge without FM (FP0), dried biogas sludge with 2% FM (FP1) and dried biogas sludge with 4% FM (FP2). Each was added to the media of white oyster mushroom as much as 5% as substitute material for bran. BP0 and FP0 created from white oyster mushroom media were commonly used by farmers. Each treatment was analyzed of nutritional and biological contents. All the data were tested using completely randomized design one-way ANOVA.

RESULTS

The results of the research on the use of chicken blood meal and fishmeal showed that the best treatments were BP2 and FP2. Their nutrient content increased, including the organic-C, organic matter, nitrogen, P2O5 and K2O. The productivity of the oyster mushroom increased, shown by the increase of fresh weight and diameter of caps in treatment BP2. The replacement of bran by biogas sludge with 4% FM addition (FP2) in oyster mushroom media increased the fresh weight, the number of caps and the length of oyster mushroom stalks.

CONCLUSION

The best treatments for mushroom media were BP2 and FP2 to be used as substitute material for bran in white oyster mushroom media.

Genome-Wide Characterization and Expression Analyses of Pleurotus ostreatus MYB Transcription Factors during Developmental Stages and under Heat Stress Based on de novo Sequenced Genome

Pleurotus ostreatus is a commercially grown mushroom species in China. However, studies on the mechanisms of the fruiting body development and stress response of P. ostreatus are still at a primary stage. In this study, we report the entire genome sequence of P. ostreatus CCMSSC03989. Then, we performed comprehensive genome-wide characterization and expression analysis of the MYB transcription factor family during a series of developmental stages and under the condition of heat stress. A 34.76 Mb genome was obtained through next-generation sequencing (NGS) and Bionano optical mapping approaches. The genome has a scaffold N50 of 1.1 Mb and contains 10.11% repeats, and 10,936 gene models were predicted. A total of 20 MYB genes (PoMYB) were identified across the genome, and the full-length open reading frames were isolated. The PoMYBs were classified into 1 repeat (1R), 2R, and 3R-MYB groups according to their MYB domain repeat numbers, and 3R-MYBs possessed relatively more introns than 1R and 2R-MYBs. Based on phylogenetic analysis, the PoMYBs were divided into four groups and showed close relationships with the MYB genes of plants and fungi. RNA-sequencing (RNA-Seq) and quantitative PCR (qPCR) analyses revealed that PoMYB expression showed stage-specific patterns in reproductive stages and could be induced by heat stress. The P. ostreatus draft genome will promote genome-wide analysis, and our study of PoMYBs will promote further functional analysis of MYB genes in mushrooms.

Toward an Increased Functionality in Oyster ( Pleurotus) Mushrooms Produced on Grape Marc or Olive Mill Wastes Serving as Sources of Bioactive Compounds

Pleurotus ostreatus, P. eryngii, and P. nebrodensis were cultivated on nonconventional substrates containing grape marc (GMC) or olive mill byproducts (OMB); wheat straw (WHS) served as control. GMC-based media demonstrated equal/better mushroom productivity than WHS for P. eryngii and P. nebrodensis, while the cultivation performance of P. eryngii was improved in OMB-based media. Both GMC and OMB substrates led to large increase of fruit-bodies content in phenolic acids, resveratrol, triterpenic compounds, and ergosterol; in particular, P. eryngii mushrooms presented significantly more total phenolics and exhibited much higher antioxidant activity (2- to 8-fold increase). Furthermore, substrates containing GMC or OMB presented up to 27% increase in mushroom β-glucans. Overall, Pleurotus species responded in a different and mostly substrate-specific manner by selectively absorbing organic compounds. Phenolics and squalene content of substrates correlated very well with mushrooms antioxidant activity and ergosterol, respectively; the same was observed for triterpenics' content of substrates and mushrooms.

Submerged Cultivation of Pleurotus sapidus with Molasses: Aroma Dilution Analyses by Means of Solid Phase Microextraction and Stir Bar Sorptive Extraction

The basidiomycete Pleurotus sapidus (PSA) was grown in submerged cultures with molasses as substrate for the production of mycelium as a protein source for food applications. The volatilomes of the substrate, the submerged culture, and the mycelia were analyzed by gas chromatography-tandem mass spectrometry-olfactometry. For compound identification, aroma dilution analyses by means of headspace solid phase microextraction and stir bar sorptive extraction were performed via variation of the split vent flow rate. Among the most potent odorants formed by PSA were arylic compounds (e.g., p-anisaldehyde), unsaturated carbonyls (e.g., 1-octen-3-one, ( E)-2-octenal, ( E, E)-2,4-decadienal), and cyclic monoterpenoids (e.g., 3,9-epoxy- p-menth-1-ene, 3,6-dimethyl-3a,4,5,7a-tetrahydro-1-benzofuran-2(3 H)-one). Several compounds from the latter group were described for the first time in Pleurotus spp. After separation of the mycelia from the medium, the aroma compounds were mainly enriched in the culture supernatant. The sensory analysis of the mycelium correlated well with the instrumental results.

A novel biodegradation pathway of the endocrine-disruptor di(2-ethyl hexyl) phthalate by Pleurotus ostreatus based on quantum chemical investigation

Di(2-ethyl hexyl) phthalate (DEHP) is a plasticizer that interfere with endocrine systems in mammals. Growth parameters for Pleurotus ostreatus grown on media containing glucose and different concentrations of DEHP (0, 500 and 1000mg/L) were evaluated. The highest biomass production was observed in medium supplemented with 1000mg of DEHP/L. Half-life of DEHP biodegradation, biodegradation constant of DEHP, and percentage of removal efficiency (%E) were also determined. P. ostreatus degraded 100% of DEHP after 504h. %E was 99.3% and 98.4% for 500 and 1000mg of DEHP/L, respectively. Intermediate compounds of biodegraded DEHP were identified by GC-MS and a DEHP biodegradation pathway was proposed using quantum chemical investigation. DEHP might be metabolized through three pathways; a de-esterification pathway, an oxidation pathway and an oxidation-hydrolysis pathway, forming phthalic acid, acetic acid and butanediol, respectively. P. ostreatus degrades and uses (as carbon and energy source) high concentrations of DEHP.

Establishment of an efficient transformation system for Pleurotus ostreatus

Pleurotus ostreatus is widely cultivated worldwide, but the lack of an efficient transformation system regarding its use restricts its genetic research. The present study developed an improved and efficient Agrobacterium tumefaciens-mediated transformation method in P. ostreatus. Four parameters were optimized to obtain the most efficient transformation method. The strain LBA4404 was the most suitable for the transformation of P. ostreatus. A bacteria-to-protoplast ratio of 100:1, an acetosyringone (AS) concentration of 0.1 mM, and 18 h of co-culture showed the best transformation efficiency. The hygromycin B phosphotransferase gene (HPH) was used as the selective marker, and EGFP was used as the reporter gene in this study. Southern blot analysis combined with EGFP fluorescence assay showed positive results, and mitotic stability assay showed that more than 75% transformants were stable after five generations. These results showed that our transformation method is effective and stable and may facilitate future genetic studies in P. ostreatus.

High temperature enhances the ability of Trichoderma asperellum to infect Pleurotus ostreatus mycelia

Trichoderma asperellum is one of the species which can be isolated from contaminated Pleurotus ostreatus cultivation substrate with green mold disease. This study focused on the relationship between high temperature and infectivity of T. asperellum to P. ostreatus. Antagonism experiments between T. asperellum and P. ostreatus mycelia revealed that high temperature-treated P. ostreatus mycelia were more easily infected by T. asperellum and covered by conidia. Microscopic observation also showed that P. ostreatus mycelia treated with high temperature could adsorb more T. asperellum conidia. Furthermore, conidia obtained from T. asperellum mycelia grown at 36°C featured higher germination rate compared with that incubated at 28°C. High temperature-treated T. asperellum mycelia can produce conidia in shorter periods, and T. asperellum mycelia were less sensitive to high temperature than P. ostreatus. Deactivated P. ostreatus mycelia can induce T. asperellum cell wall-degrading enzymes (CWDEs) and P. ostreatus mycelia subjected to high temperature showed induced CWDEs more effective than those incubated at 28°C. Moreover, T. asperellum showed higher CWDEs activity at high temperature. In dual cultures, hydrogen peroxide (H₂O₂) increased after 36°C, and high concentration of H₂O₂ could significantly inhibit the growth of P. ostreatus mycelia. In summary, our findings indicated for the first time that high temperature can induce a series of mechanisms to enhance infection abilities of T. asperellum to P. ostreatus mycelia and to cause Pleurotus green mold disease.

Bioremediation of aflatoxin B1-contaminated maize by king oyster mushroom (Pleurotus eryngii)

Aflatoxin B1 (AFB₁) is the most harmful mycotoxin that occurs as natural contaminant of agricultural commodities, particularly maize. Practical solutions for detoxification of contaminated staples and reduction of agricultural wastes are scarce. We investigated the capability of the white-rot and edible fungus Plerotus eryngii (king oyster mushroom) to degrade AFB₁ both in vitro and in a laboratory-scale mushroom cultivation, using a substrate similar to that routinely used in mushroom farms. In malt extract broth, degradation of AFB₁ (500 ng/mL) by nine isolates of P. eryngii ranged from 81 to 99% after 10 days growth, and reached 100% for all isolates after 30 days. The growth of P. eryngii on solid medium (malt extract-agar, MEA) was significantly reduced at concentrations of AFB₁ 500 ng/mL or higher. However, the addition of 5% wheat straw to the culture medium increased the tolerance of P. eryngii to AFB₁ and no inhibition was observed at a AFB₁ content of 500 ng/mL; degradation of AFB₁ in MEA supplemented with 5% wheat straw and 2.5% (w/v) maize flour was 71–94% after 30 days of growth. Further, AFB₁ degradation by P. eryngii strain ITEM 13681 was tested in a laboratory-scale mushroom cultivation. The mushroom growth medium contained 25% (w/w) of maize spiked with AFB₁ to the final content of 128 μg/kg. Pleurotus eryngii degraded up to 86% of the AFB₁ in 28 days, with no significant reduction of either biological efficiency or mushroom yield. Neither the biomass produced on the mushroom substrate nor the mature basidiocarps contained detectable levels of AFB₁ or its metabolite aflatoxicol, thus ruling out the translocation of these toxins through the fungal thallus. These findings make a contribution towards the development of a novel technology for remediation of AFB₁- contaminated corn through the exploitation of the degradative capability of P. eryngii and its bioconversion into high nutritional value material intended for feed production.

Valorization of spent oyster mushroom substrate and laccase recovery through successive solid state cultivation of Pleurotus, Ganoderma, and Lentinula strains

Spent mushroom substrate (SMS) of Pleurotus ostreatus was supplemented with wheat bran and soybean flour in various proportions to obtain C/N ratios of 10, 20, and 30, and their effect was evaluated in successive cultivation of Pleurotus ostreatus, Pleurotus pulmonarius, Ganoderma adspersum, Ganoderma resinaceum, and Lentinula edodes strains with respect to mycelium growth rate, biomass concentration, recovery of the enzyme laccase and crude exopolysaccharides, and also with additional fruiting body production. All fungi showed the highest growth rate on unamended SMS (C/N 30), with G. resinaceum being the fastest colonizer (Kr = 9.84 mm day-1), while biomass concentration maximized at C/N 10. Moreover, supplementation affected positively laccase activity, with P. pulmonarius furnishing the highest value (44,363.22 U g-1) at C/N 20. On the contrary, L. edodes growth, fruiting, and laccase secretion were not favored by SMS supplementation. Fruiting body formation was promoted at C/N 30 for Ganoderma and at C/N 20 for Pleurotus species. Exopolysaccharide production of further studied Pleurotus strains was favored at a C/N 20 ratio, at the initial stage of SMS colonization. The obtained results support the potential effective utilization of supplemented SMS for laccase production from Ganoderma spp. and for new fruiting body production of Pleurotus spp.

Mycochemical Changes Induced by Selenium Enrichment in P. ostreatus Fruiting Bodies

The effects of selenium enrichment on the biological efficiency, phenolic compounds, amino acid profile, antioxidant capacity, and cellular antioxidant activity (CAA) were evaluated in Pleurotus ostreatus fruiting bodies (FB) harvested during three sequential flushes. Sodium selenate was used to reach selenium content of 17.5 or 5.8 mg/kg in the sorghum straw substrate. Biological efficiency and total selenium content increased. One of the main differences among treatments was in ergothioneine content, an indicator of oxidative stress that was positively related with valine and isoleucine contents and negatively related to leucine and phenylalanine. Besides ergothioneine, nucleosides derived from adenine and uracyl were the major peaks observed in all treatments, and coumaric and ferulic acids were found in the bound phenolics extract. Selenium enrichment also affected the antioxidant capacity, and particularly the methanolic extract obtained from the second flush of FB cultivated in selenium-enriched substrate (17.5 mg/kg) had the best CAA.

Mechanisms of Cd and Cr removal and tolerance by macrofungus Pleurotus ostreatus HAU-2

Fungi bioaccumulation is a novel and highly promising approach to remediate polluted soil. The present study revealed a high ability to tolerate Cd and Cr in the fungus Pleurotus ostreatus HAU-2. However, high concentrations of Cd and Cr can suppress fungal growth and result in a variation of hypha micromorphology. Batch experiments were performed to investigate Cd and Cr stress effects on the amount of active oxygen in fungi, activity of antioxidant enzyme, as well as the removal efficiency of Cd and Cr. The results revealed that Cd and Cr caused increasing active oxygen and malonaldehyde (MDA) concentrations. Antioxidant enzymes play a central role in removing active oxygen, while glutathione (GSH) aids the Cd detoxification within cells. In fluid culture, fungal removal rates of Cd and Cr ranged from 44.85% to 80.36% and 14.49% to 45.55%, respectively. Intracellular accumulation and extracellular adsorption were the major removal approaches. Bag cultivation testing indicated that the fungus absorbed Cd and Cr contained within soil. In particular, the accumulation ability of Cd (15.6mgkg^-1) was higher compared to that of Cr (8.9mgkg^-1). These results successfully establish P. ostreatus HAU-2 as promising candidate for the remediation of heavy-metal polluted soils.

Bioremediation of long-term PCB-contaminated soil by white-rot fungi

The objective of this work was to test the PCB-degrading abilities of two white-rot fungi, namely Pleurotus ostreatus and Irpex lacteus, in real contaminated soils with different chemical properties and autochthonous microflora. In addition to the efficiency in PCB removal, attention was given to other important parameters, such as changes in the toxicity and formation of PCB transformation products. Moreover, structural shifts and dynamics of both bacterial and fungal communities were monitored using next-generation sequencing and phospholipid fatty acid analysis. The best results were obtained with P. ostreatus, which resulted in PCB removals of 18.5, 41.3 and 50.5% from the bulk, top (surface) and rhizosphere, respectively, of dumpsite soils after 12 weeks of treatment. Numerous transformation products were detected (hydoxylated and methoxylated PCBs, chlorobenzoates and chlorobenzyl alcohols), which indicates that both fungi were able to oxidize and decompose the aromatic moiety of PCBs in the soils. Microbial community analysis revealed that P. ostreatus efficiently colonized the soil samples and suppressed other fungal genera. However, the same fungus substantially stimulated bacterial taxa that encompass putative PCB degraders. The results of this study finally demonstrated the feasibility of using this fungus for possible scaled-up bioremediation applications.

Effect of supplementing crop substrate with defatted pistachio meal on Agaricus bisporus and Pleurotus ostreatus production

BACKGROUND

This work assesses the agronomic performance of defatted pistachio meal, after oil extraction, as a nutritional substrate supplement when growing the mushroom species Agaricus bisporus (Lange) Imbach and Pleurotus ostreatus (Jacq.) P. Kumm. Materials were applied at different doses at spawning. Along with non-supplemented substrates, commercial nutritional supplements were used as controls. Proximate analysis of mushrooms is also considered.

RESULTS

For the cultivation of champignon, defatted pistachio meal has provided larger mushrooms (unitary weight and cap diameter) with firmer texture and greater content in dry weight and protein, without significant alterations in quantitative parameters. For Pleurotus ostreatus, the supplement led to significant yield increase, even providing up to 34.4% of increment compared to non-supplementation with meal, reaching a biological efficiency of 129.9 kg dt(-1) , when applied to the 15 g kg(-1) compost dose. Supplementation has also been conducted to increase dry weight, protein and fibre within carpophores and to decrease the energy value. Defatted pistachio meal has similar or better results compared to the commercial supplements used as reference.

CONCLUSIONS

Compost supplementation with defatted pistachio meal in A. bisporus concerns mainly the quantitative parameters (size, texture, dry weight and protein). Based on the results obtained, this technique has greater potential of development for P. ostreatus commercial crops, basically due to expected increases in production, with a direct impact on benefits and crop profitability. © 2015 Society of Chemical Industry.

De Novo Sequencing and Transcriptome Analysis of Pleurotus eryngii subsp. tuoliensis (Bailinggu) Mycelia in Response to Cold Stimulation

Cold stimulation of Bailinggu's mycelia is the main factor that triggers primordia initiation for successful production of fruiting bodies under commercial cultivation. Yet, the molecular-level mechanisms involved in mycelia response to cold stimulation are still unclear. Here, we performed comparative transcriptomic analysis using RNA-Seq technology to better understand the gene expression regulation during different temporal stages of cold stimulation in Bailinggu. A total of 21,558 Bailinggu mycelia unigenes were de novo assembled and annotated from four libraries (control at 25 °C, plus cold stimulation treatments at -3 °C for a duration of 1-2 days, 5-6 days, and 9-10 days). GO and KEGG pathway analysis indicated that functional groups of differentially expressed unigenes associated with cell wall and membrane stabilization, calcium signaling and mitogen-activated protein kinases (MAPK) pathways, and soluble sugars and protein biosynthesis and metabolism pathways play a vital role in Bailinggu's response to cold stimulation. Six hundred and seven potential EST-based SSRs loci were identified in these unigenes, and 100 EST-SSR primers were randomly selected for validation. The overall polymorphism rate was 92% by using 10 wild strains of Bailinggu. Therefore, these results can serve as a valuable resource for a better understanding of the molecular mechanisms associated with Bailinggu's response to cold stimulation.

Evaluation of productivity and antioxidant profile of solid-state cultivated macrofungi Pleurotus albidus and Pycnoporus sanguineus

The aim of this study was to investigate the production profile of Pleurotus albidus and Pycnoporus sanguineus on different waste substrates containing natural phenolics, and also to investigate whether phenolic-rich substrates can improve the phenolic content of these macrofungi. The medium formulated with Pinus sp. sawdust (PSW) made possible the highest yields (2.62±0.73%) of P. sanguineus. However, the supplementation of PSW with apple waste (AW) resulted in better P. albidus yields (23.94±2.92%). The results indicated that the substrate composition affected macrofungi production, also the chemical composition and the presence of phenolic compounds in the production media influence phenolic content and antioxidant activity in macrofungi.

Tea waste: an effective and economic substrate for oyster mushroom cultivation

BACKGROUND

Tea waste is the residue that remains after tea leaves have been extracted by hot water to obtain water-soluble components. The waste contains a re-usable energy substrate and nutrients which may pollute the environment if they are not dealt with appropriately. Other agricultural wastes have been widely studied as substrates for cultivating mushrooms. In the present study, we cultivated oyster mushroom using tea waste as substrate. To study the feasibility of re-using it, tea waste was added to the substrate at different ratios in different experimental groups. Three mushroom strains (39, 71 and YOU) were compared and evaluated. Mycelia growth rate, yield, biological efficiency and growth duration were measured.

RESULTS

Substrates with different tea waste ratios showed different growth and yield performance. The substrate containing 40-60% of tea waste resulted in the highest yield.

CONCLUSION

Tea waste could be used as an effective and economic substrate for oyster mushroom cultivation. This study also provided a useful way of dealing with massive amounts of tea waste.

Comparative evaluation of five Pleurotus species for their growth behaviour and yield performance using wheat straw as a substrate

Pleurotus spp. is one of the most important edible mushrooms cultivated in India. The present study was an attempt to compare five Pleurotus species in context of actual time required for each growth stage viz., spawn run period, number of days required for initiation of pin heads of sporophores, average weight of fruiting bodies in all the flushes and total yield. The spawn run period in all the five species were recorded between 18 days-21 days, similarly for initiation of pinheads 5 days -7 days were required after spawn run period. A total of 24 days to 27 days, 34 days to 37 days and 47 days to 53 days were required for harvesting the I, II and III flushes respectively. An average number of 41 to 70 sporophores per bag containing 1 kg of dry substrates were obtained from all the Pleurotus species. Maximum 14 g weight of single sporophore was recorded from P. florida, similarly, an average maximum diameter of 5.3 cm of sporophores of P. florida was observed whereas the diameter of sporophores in rest of the species ranged from 3.0 cm to 3.2 cm. The number of sporophores were obtained from P. sajor-caju (n-70) and all the species showed significant difference with respect to the number of sporophores in a bunch at probability level of P = 0.05. Maximum weight of single bunch was recorded (58 g) in P. florida and total yield of 740 gkg(-1) of dry matter was recorded in P. florida.

Alleviating the toxicity of heavy metals by combined amendments in cultivated bag of Pleurotus cornucopiae

The substrate of mushroom can be polluted with heavy metals and subsequently contaminate mushroom, which requires alternative solutions to reduce associated environmental and human health risks. The effects of amendment application on alleviating Cu and Cd toxicities to Pleurotus cornucopiae were investigated in a cultivated bag experiment conducted with the naturally contaminated substrate. Addition of combined amendments (sodium bentonite, silicon fertilizer, activated carbon, and potassium dihydrogen phosphate) increased the P. cornucopiae biomass and substrate pH. Cu and Cd concentration in P. cornucopiae as well as the available Cu and Cd in substrate reduced for the presence of amendments, and the silicon fertilizer had the biggest inhibition on metal uptake. The smallest amount of Cu and Cd in P. cornucopiae was only 30.8 and 5.51% of control, respectively. Moreover, application of amendments also decreased malondialdehyde (MDA) and hydrogen peroxide (H2O2) level in metal-stressed mushroom by 4.38-53.74 and 8.90-58.42% relative to control, respectively. The decreased oxidative stress could well contribute to the growth of P. cornucopiae, and the elevated substrate pH might lead to the lower metal availability, thus resulting in the reduction of metal accumulation in mushroom. These above results suggest that application of combined amendments in mushroom substrate could be implemented in a general scheme aiming at controlling metal content in P. cornucopiae.

Transformation Pathways of the Recalcitrant Pharmaceutical Compound Carbamazepine by the White-Rot Fungus Pleurotus ostreatus: Effects of Growth Conditions

The widely used anticonvulsant pharmaceutical carbamazepine is recalcitrant in many environmental niches and thus poses a challenge in wastewater treatment. We followed the decomposition of carbamazepine by the white-rot fungus Pleurotus ostreatus in liquid culture compared to solid-state fermentation on lignocellulosic substrate where different enzymatic systems are active. Carbamazepine metabolites were identified using liquid chromatography-high-resolution mass spectrometry (LC-Q-TOF-MS). In liquid culture, carbamazepine was only transformed to 10,11-epoxy carbamazepine and 10,11-dihydroxy carbamazepine as a dead-end product. During solid-state fermentation, carbamazepine metabolism resulted in the generation of an additional 22 transformation products, some of which are toxic. Under solid-state-fermentation conditions, 10,11-epoxy carbamazepine was further metabolized via acridine and 10,11-dihydroxy carbamazepine pathways. The latter was further metabolized via five subpathways. When (14)C-carbonyl-labeled carbamazepine was used as the substrate, (14)C-CO2 release amounted to 17.4% of the initial radioactivity after 63 days of incubation. The proposed pathways were validated using metabolites (10,11-epoxy carbamazepine, 10,11-dihydroxy carbamazepine, and acridine) as primary substrates and following their fate at different time points. This work highlights the effect of growth conditions on the transformation pathways of xenobiotics. A better understanding of the fate of pollutants during bioremediation treatments is important for establishment of such technologies.

New apoptosis-inducing sesquiterpenoids from the mycelial culture of Chinese edible fungus Pleurotus cystidiosus

Two new bisabolane-type sesquiterpenoids, pleuroton A (1) and pleuroton B (2), and three clitocybulol derivatives, clitocybulol D (3), clitocybulol E (4), and clitocybulol F (5), were obtained from the mycelial culture of edible fungus Pleurotus cystidiosus O. K. Mill by repeated column chromatography over RP-18, Sephadex LH-20, and silica gel. Their structures were determined according to nuclear magnetic resonance data, high-resolution electron impact mass spectrometry, and circular dichroism spectra. These new sesquiterpenoids exhibited significant cytotoxicity against two human prostate cancer DU-145 and C42B cells in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The median inhibitory concentration (IC50) of compounds 1, 2, 3, 4, and 5 was 174, 28, 233, 162, and 179 nM, respectively, against the DU-145 cell and was 104, 52, 163, 120, and 119 nM, respectively, against the C42B cell. Especially, pleuroton B (2) exhibited the strongest cytotoxity among these sesquiterpenoids, which was confirmed by the colony formation assay. Furthermore, pleuroton B (2) could trigger the apoptosis of DU-145 cells through the detection of apoptosis cells using annexin V-FITC staining by flow cytometry, the observation of condensed nuclei in the apoptosis cells, and the western blot analysis for the expression of apoptosis-related proteins Bcl-2, Bak, and Bax. Analysis of structure-activity relationships of these sesquiterpenoids revealed that the unusual functional moiety of pleuroton B should contribute to its significant bioactivity. These results display the pharmacological potential of P. cystidiosus.

Biosorption of aquatic copper (II) by mushroom biomass Pleurotus eryngii: kinetic and isotherm studies

Biosorption is an effective method for removing heavy metals from effluent. This work mainly aimed to evaluate the adsorption performance of the widely cultivated novel mushroom, Pleurotus eryngii, for the removal of Cu(II) from single aqueous solutions. Kinetics and equilibria were obtained using a batch technique. The sorption kinetics follows the pseudo-second-order model, whereas the adsorption equilibria are best described by the Langmuir model. The adsorption process is exothermic because both the Langmuir-estimated biosorption capacity and the heat of adsorption estimated from the Temkin model decreased with increasing tested temperature. Based on the adsorption intensity estimated by the Freundlich model and the mean adsorption free energy estimated by the Dubinin-Radushkevich model, the type of adsorption is defined as physical adsorption. The biomass of the macro-fungus P. eryngii has the potential to remove Cu(II) from a large-scale wastewater contaminated by heavy metals, because of its favorable adsorption, short biosorption equilibrium time of 20 min and remarkable biosorption capacity (15.19 mg g⁻¹ as calculated by the Langmuir model). The adsorbed metal-enriched mushroom is a high-quality bio-ore by the virtue of its high metal content of industrial mining grade and easy metal extractability.

Changes in chemical components and cytotoxicity at different maturity stages of Pleurotus eryngii fruiting body

The present study investigated the changes of the chemical components and cytotoxicity potency at 5 developmental stages of Pleurotus eryngii fruiting body. The carbohydrate and protein contents increased along the maturity of fruiting body while fat content decreased. By comparison, the polysaccharide-protein fractions had the highest antiproliferative effect on SGC-7901 and HepG-2 cells in vitro and increasing activity with growing maturity of P. eryngii fruiting body.The maturation process increased the protein content and acid property through the enhanced relative abundance of Asp, Thr, and Glu in polysaccharide-protein fractions. Further purification and electrophoresis identified that the polysaccharide-protein PEG-1with three subunits possibly was the target cytotoxical component. Our findings proved that mature fruiting body of P. eryngii containing these polysaccharide-proteins possessed highly nutritional values and therapeutical benefits.

Bioremediation of vegetable and agrowastes by Pleurotus ostreatus: a novel strategy to produce edible mushroom with enhanced yield and nutrition

Pleurotus ostreatus was grown on paddy straw as well as other vegetable and agricultural wastes i.e. pea pod shell, cauliflower leaves, radish leaves and brassica straw in various combinations with paddy straw. The mushroom did not grow on the vegetable wastes separately. The cumulative yield and biological efficiency of the edible oyster mushroom P. ostreatus grown on substrate containing paddy straw in various combinations with different vegetable wastes i.e. 20% and 30 % vegetable wastes mixed with 80% and 70% (w/w) of paddy straw was found to be better, when compared with yield and biological efficiency obtained on paddy straw (100%) alone. The protein content and six essential amino acid contents (Leu, Ile, Val, Thr, Met, Phe) showed a significant increase and total sugar and reducing sugar contents showed decrease in the mushroom fruit bodies grown at different combinations of vegetable wastes with paddy straw as compared to paddy straw alone. However, there was not any significant change in moisture content of mushroom cultivated on different groups of wastes. Hence, results of this investigation suggest that the vegetable wastes which are generally left to rot in situ in many cities and villages causing outbreak of diseases can be bioremediated by edible mushroom P. ostreatus. The added advantage is that we get edible mushroom fruit body with improved nutrition.

Morphology and mycelial growth rate of Pleurotus spp. strains from the Mexican mixtec region

Two native Pleurotus spp. strains (white LB-050 and pale pink LB-051) were isolated from rotten tree trunks of cazahuate (Ipomoea murucoides) from the Mexican Mixtec Region. Both strains were chemically dedikaryotized to obtain their symmetrical monokaryotic components (neohaplonts). This was achieved employing homogenization time periods from 60 to 65 s, and 3 day incubation at 28 °C in a peptone-glucose solution (PGS). Pairing of compatible neohaplonts resulted in 56 hybrid strains which were classified into the four following hybrid types: (R(1-n)xB(1-n), R(1-n)xB(2-1), R(2-n)xB(1-n) and R(2-n)xB(2-1)). The mycelial growth of Pleurotus spp. monokaryotic and dikaryotic strains showed differences in texture (cottony or floccose), growth (scarce, regular or abundant), density (high, regular or low), and pigmentation (off-white, white or pale pink). To determine the rate and the amount of mycelium growth in malt extract agar at 28 °C, the diameter of the colony was measured every 24 h until the Petri dish was completely colonized. A linear model had the best fit to the mycelial growth kinetics. A direct relationship between mycelial morphology and growth rate was observed. Cottony mycelium presented significantly higher growth rates (p < 0.01) in comparison with floccose mycelium. Thus, mycelial morphology can be used as criterion to select which pairs must be used for optimizing compatible-mating studies. Hybrids resulting from cottony neohaplonts maintained the characteristically high growth rates of their parental strains with the hybrid R(1-n)xB(1-n) being faster than the latter.

A novel stirrer design and its application in submerged fermentation of the edible fungus Pleurotus ostreatus

In this study, a straight diagonal-pitched blade stirrer was designed, built and characterized in a 5-L fermenter. Compared with the six straight blade Rushton turbine, the power consumption of the new stirrer is lower at a given speed under conditions of no ventilation. The oxygen transference is poorer at the same agitation speed in the cultivation conditions and scales investigated, which confirms that the shear stress of the new stirrer is lower and the gas dispersion is weaker. The new stirrer was installed in a 5-L bioreactor and evaluated in submerged fermentation of the edible fungus Pleurotus ostreatus. The results showed that the maximum dry weight of mycelium is increased by 47 % and reached 7.47 g/L, and the maximum laccase activity is increased by 15 % up to 2,277 U/L. Glucose consumption was also found to be relatively faster. The power consumption is 2.8 % lower than that of the Rushton turbine.

Mushroom dietary fiber from the fruiting body of Pleurotus tuber-regium: fractionation and structural elucidation of nondigestible cell wall components

The cell wall of mushroom fruiting body is constituted of nondigestible macromolecules that are a rich source of dietary fiber with biological functions that are beneficial to human health. The cell wall components of an edible mushroom fruiting body from Pleurotus tuber-regium (PTR) were fractionated, and their chemical structures were investigated by chemical, physicochemical, and microscopic analyses. The present results suggest that the cell wall of the PTR mushroom fruiting body contains four main fractions: an outer fraction of polysaccharide and protein complex, which can be extracted using boiling water; a cold alkali-soluble fraction of heteropolysaccharides associated with a small amount of proteins; a hot alkali-soluble fraction of hyper-branched glucans; and an alkali-insoluble fraction of glucan-chitin complex with a normalized relative percentage of 3.6:21.9:55.7:18.8. The anomeric linkage of all the glucans was revealed by infrared spectroscopy to be β type. The structure of the major mushroom fruiting body cell wall polysaccharide (the hot alkali-soluble one, FHA-I) was elucidated by the methylation analysis to be composed of →1)-Glcp-(4→ linkages as the backbone with a 52% degree of branching consisting of →1)-Glcp-(6→ linkages in the side chains, whereas some →1)-Glcp-(3→ linkages might exist in the backbone or side chains. Size exclusion chromatography coupled with multiangle laser light scattering analysis revealed that FHA-I had a molecular weight of 4.224 × 10(6) g/mol and a root-mean-square radius of 30.4 nm. Both scanning electron and atomic force microscopy further showed the highly branched microstructure of FHA-I when dispersed in an aqueous sodium dodecyl sulfate solution.

Isolation, culture optimization and physico-chemical characterization of laccase enzyme from Pleurotus fossulatus

Pleurotus fossulatus (Cooke) Sace is member of oyster mushroom can produced extracellular laccase (benzenediol: oxygen oxidoreductase; EC 1.10.3.2) in submerged fermentation. To analyze the optimum production for laccase P. fossulatus was cultured both in stationary and shaking condition in different media. Partial purification of laccase was done after 0-80% ammonium sulphate precipitation, followed by DEAE (Diethylaminoethyl) Sephadex (A-50) anion exchange chromatography. Potato-sucrose peptone (PSP) medium and Potato-dextrose (PD) medium showed highest laccase production in shaking and stationary conditions, respectively. Though the time required for optimum laccase production in stationary condition was much more than the shaking condition but the amount of laccase was about 2.75t greater in former condition. The laccase produced in stationary condition was more stable than the enzyme produced in shaking condition. The partially purified enzyme showed highest affinity towards o-dianisidine than guaiacol and ABTS (2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) as evidenced by their K(m). The physico-chemical properties of the laccase suggested the significance of this enzyme in industrial applications.

Evaluation of biomass of some invasive weed species as substrate for oyster mushroom (Pleurotus spp.) cultivation

This study assessed the bioconversion of Agriculture wastes like invasive weeds species (Lantana camara, Prosopis juliflora, Parthenium hysterophorus) as a substrate for oyster mushroom (Pleurotus species) cultivation together with wheat straw as a control. The experiment was laid out in factorial combination of substrates and three edible oyster mushroom species in a Completely Randomized Design (CRD) with three replications. Pleurotus ostreatus gave significantly (p < 0.01) total yield of 840 g kg(-1) on P. hysterophorus, Significantly (p < 0.01) biological efficiency (83.87%) and production rate of 3.13 was recorded for P. ostreatus grown on P. hysterophorus. The highest total ash content (13.90%) was recorded for P. florida grown on L. camara. while the lowest (6.92%) was for P. sajor-caju grown on the P. juliflora. Crude protein ranged from 40.51-41.48% for P. florida grown on P. hysterophorus and L. camara. Lowest crude protein content (30.11%) was recorded for P. ostreatus grown on wheat straw. The crude fiber content (12.73%) of P. sajor-caju grown on wheat straw was the highest. The lowest crude fiber (5.19%) was recorded for P. ostreatus on P. juliflora. Total yield had a positive and significant correlation with biological efficiency and production. Utilization of the plant biomass for mushroom cultivation could contribute to alleviating ecological impact of invasive weed species while offering practical option to mitigating hunger and malnutrition in areas where the invasive weeds became dominant.

Valorization of solid olive mill wastes by cultivation of a local strain of edible mushrooms

Olive oil industry generates huge quantities of solid olive mill wastes (SOMW), causing environmental damage. Cultivation of edible mushrooms, such as Pleurotus ostreatus is a valuable approach for SOMW valorization. A local strain mycelium (Tizi-Ouzou, Algeria) of P. ostreatus (LPO) was isolated from castor oil plants. Oyster mushroom spawn, produced on barley grains, was used to inoculate wet SOMW, steamed in a traditional steamer during 45 min. The mycelium growth rate on SOMW was first estimated in Petri dish by measuring the surface colonized by the mycelium. The fruit body yields were estimated on culture bags containing 2 kg each of SOMW inoculated at 7% (w/w). The local strain potential was compared with that of a commercial one. Both strains produced high-quality mushrooms, but with low yields. The supplementation of the SOMW with wheat straw at the rate of 10% and 2% of CaCO3 had significantly enhanced the productivity of the two strains, multiplying it by 3.2 for LPO and by 2.6 for CPO.

Induction of laccase activity in the white rot fungus Pleurotus ostreatus using water polluted with wheat straw extracts

The purpose of this work was to explore the use of polluted water effluents from wheat straw using industries as inducers of lignocellulolytic enzymatic activities in cultures of white rot basidiomycetes. For this purpose, we studied the effect of a wheat straw water extract on the evolution of the laccase activity recovered from submerged cultures of Pleurotus ostreatus made in different media and under various culture conditions. Our results demonstrated an accumulative induction effect in all the cultures and conditions tested. This induction is parallel to changes in the laccase electrophoretic profiles recovered from the culture supernatants. The isoenzyme that appeared to be mainly responsible for the laccase activity under these conditions was laccase 10, as confirmed by sequencing the induced protein. These results support the idea of using wheat straw effluents as inducers in liquid cultures of P. ostreatus mycelia for the production of ligninolytic enzymatic cocktails.

[White-rot fungi combinations impact on enzyme productions]

In this study, the maximum laccase (Lac) activities by single white-rot fungus and combining white-rot fungi were investigated. The optimal combinations of white-rot fungi were obtained by comparing the maximum Lac activities and the time of achieving the maximum Lac activity. The results showed that the synergy of white-rot fungi Polyporellus picipes and Pleurotus ostreatus improved the secretion of the laccase, with the enzyme production of 50.45 U x mL(-1), as well as the combination of white-rot fungi Polyporellus picipes, Pleurotus ostreatus and Pseudotrametes gibbosa promoted the laccase production of 75.98 U x mL(-1). However, the combination of white-rot fungi Polyporellus picipes, Pleurotus ostreatus and Pycnoporus sanguineus generated antagonistic effect, with the enzyme production of 2.91 U x mL(-1). Both synergistic and antagonistic effects among the white-rot fungi results in different time for achieving the maximum Lac activity of white-rot fungi.

Biodegradation of vegetable and agrowastes by Pleurotus sapidus: a novel strategy to produce mushroom with enhanced yield and nutrition

Edible oyster mushroom Pleurotus sapidus was cultivated, on pea pod shell, cauliflower leaves, radish leaves, brassica straw in various combinations of paddy straw. The mushroom failed to grow on these vegetable wastes separately. However, it grew very well on these vegetable wastes when mixed with various combinations of paddy straw as substrate. Total yield and biological efficiency of the mushroom cultivated on substrate containing 20% and 30% vegetable wastes mixed with 70% and 80% (w/w) of paddy straw was found to be better, when compared with yield and efficiency obtained with paddy straw alone (100%). The protein content in the fruit bodies was found to be higher in the mushroom grown on paddy straw mixed with vegetable wastes than that obtained with paddy straw alone. Similarly, six amino acids (Leu, Ile, Val, Thr, Met and Phe) showed a significant increase when the mushroom was grown on a mixed substrate containing both vegetable wastes and paddy straw. On the contrary, the total sugar and reducing sugar content declined in the mushroom grown on the mixture of paddy straw and other wastes, when compared with the results obtained with paddy straw alone.

Antioxidant and antitumor activities of selenium- and zinc-enriched oyster mushroom in mice

Selenium and zinc are well-known essential trace elements with potent biological functions. However, the possible health benefits of the combined administration of dietary selenium and zinc have not been studied extensively. In this study, we prepared selenium- and zinc-enriched mushrooms (SZMs) containing increased levels of selenium and zinc. The effects of SZMs on antioxidant and antitumor activities were evaluated. Mice were fed with either a control diet or a diet supplemented with SZMs or sodium selenite and zinc sulfate for 6 weeks. Antioxidant capacity was investigated by measuring the activities of antioxidant enzymes and the levels of lipid peroxide products. Results showed that treatment with SZMs significantly increased the activities of glutathione peroxidase (GPx) and superoxide dismutase and decreased the levels of malondialdehyde and lipofuscin. Furthermore, using a mouse model of lung tumors, we found that SZMs significantly decreased the number of tumor nodes with an increase in the activity of GPx. SZMs had a greater effect on the increase in both antioxidant and antitumor activities than did sodium selenite and zinc sulfate. These findings suggest that SZMs may be effective for improving antioxidant capacity and preventing tumors.

An improved sequence-aided T-RFLP analysis of bacterial succession during oyster mushroom substrate preparation

While oyster mushroom (Pleurotus spp.) is one of the most popular cultivated edible mushrooms, there is scanty information about the microbial community taking part in mushroom substrate production. In this study, an improved sequence-aided terminal restriction fragment length polymorphism (T-RFLP) was used to identify and (semi-)quantify the dominant bacteria of oyster mushroom substrate preparation. The main features of the improved T-RFLP data analysis were the alignment of chromatograms with variable clustering thresholds, the visualization of data matrix with principal component analysis ordination superimposed with cluster analysis, and the search for stage-specific peaks (bacterial taxa) with similarity percentage (analysis of similarity) analysis, followed by identification with clone libraries. By applying this method, the dominance of the following bacterial genera was revealed during oyster mushroom substrate preparation: Pseudomonas and Sphingomonas at startup, Bacillus, Geobacillus, Ureibacillus, Pseudoxanthomonas, and Thermobispora at the end of partial composting, and finally several genera of Actinobacteria, Thermus, Bacillus, Geobacillus, Thermobacillus, and Ureibacillus in the mature substrate. As the proportion of uncultured bacteria increased during the process, it is worth establishing strain collections from partial composting and from mature substrate for searching new species.

Biodegradation and detoxification of olive mill wastewater by selected strains of the mushroom genera Ganoderma and Pleurotus

Thirty-nine white-rot fungi belonging to nine species of Agaricomycotina (Basidiomycota) were initially screened for their ability to decrease olive-mill wastewater (OMW) phenolics. Four strains of Ganoderma australe, Ganoderma carnosum, Pleurotus eryngii and Pleurotus ostreatus, were selected and further examined for key-aspects of the OMW biodegradation process. Fungal growth in OMW-containing batch cultures resulted in significant decolorization (by 40-46% and 60-65% for Ganoderma and Pleurotus spp. respectively) and reduction of phenolics (by 64-67% and 74-81% for Ganoderma and Pleurotus spp. respectively). COD decrease was less pronounced (12-29%). Cress-seeds germination increased by 30-40% when OMW was treated by Pleurotus strains. Toxicity expressed as inhibition of Aliivibrio fischeri luminescence was reduced in fungal-treated OMW samples by approximately 5-15 times compared to the control. As regards the pertinent enzyme activities, laccase and Mn-independent peroxidase were detected for Ganoderma spp. during the entire incubation period. In contrast, Pleurotus spp. did not exhibit any enzyme activities at early growth stages; instead, high laccase (five times greater than those of Ganoderma spp.) and Mn peroxidases activities were determined at the end of treatment. OMW decolorization by Ganoderma strains was strongly correlated to the reduction of phenolics, whereas P. eryngii laccase activity was correlated with the effluent's decolorization.