Edible Fungus Pleurotus Ostreatus Research Articles

Efficient enzymatic hydrolysis for enriching the antioxidant content of agro‐food industrial residues

AbstractBackgroundEnzymatic hydrolysis of agro‐food industrial residues (AFIRs) has the potential of generating great economic value in the food and the cosmetics industry. Here, we develop an efficient solid enzymatic hydrolysis (SEH) employing the edible fungus Pleurotus ostreatus to enzymatically digest wheat bran. We assess the antioxidant activity of the SEH product by implementing a highly affordable antioxidant activity test (AAT). Finally, we obtain a tablet formulation containing the SEH product.ResultsResults show that the selected parameters for the SEH are highly competitive among other described SEHs that use fungi to digest wheat residues. The AAT showed a dose–response antioxidant behavior employing a known antioxidant (vitamin C). The AAT also showed that the SEH product has higher antioxidant activity than the undigested substrate. Finally, the hardness assessment of the SEH tablets suggested changes in stability.ConclusionIn conclusion, an efficient SEH was implemented and its effect on the antioxidant activity was demonstrated. The SEH could be performed at a competitive incubation time, temperature, and moisture content. Nevertheless, a deeper study is warranted to fully describe this SEH. We hope that these findings contribute to the development of cost‐efficient SEHs in the food and cosmetics industry.

Molecular characterization of a novel deltaflexivirus infecting the edible fungus Pleurotus ostreatus.

A novel positive single-stranded RNA virus, Pleurotus ostreatus deltaflexivirus 1 (PoDFV1), was isolated from the edible fungus Pleurotus ostreatus strain ZP6. The complete genome of PoDFV1 is 7706 nucleotides (nt) long and contains a short poly(A) tail. PoDFV1 was predicted to contain one large open reading frame (ORF1) and three small downstream ORFs (ORFs 2-4). ORF1 encodes a putative replication-associated polyprotein of 1979 amino acids (aa) containing three conserved domains - viral RNA methyltransferase (Mtr), viral RNA helicase (Hel), and RNA-dependent RNA polymerase (RdRp) - which are common to all deltaflexiviruses. ORFs 2-4 encode three small hypothetical proteins (15-20 kDa) without conserved domains or known biological functions. Sequence alignments and phylogenetic analysis suggested that PoDFV1 is a member of a new species in the genus Deltaflexivirus (family Deltaflexiviridae, order Tymovirales). To our knowledge, this is the first report of a deltaflexivirus infecting P. ostreatus.

First report of edible mushroom Pleurotus ostreatus from India with potential to kill plant parasitic nematodes

Edible fungus Pleurotus ostreatus was, isolated cultured and identified from the bark of Mangifera indica tree. The hyphae emerging from the fruiting body produces secretory cells with toxin droplets in water agar medium which immobilize the nematode and mostly enter from the mouth region. Earlier finding showed that trans-2-decenedioic acid toxin affects only saprophytic nematodes through the mouth part but similar observations in plant parasitic nematode Meloidogyne incognita suggested that there is no obstacle from stylet in paralysing and killing. From Indian subcontinent P. ostreatus was first time isolated, in perspective of plant parasitic nematode management in addition to mushroom production.

Asperpyrone F, a new dimeric naphtho-γ-pyrone from the edible fungus Pleurotus ostreatus

A new dimeric naphtho-γ-pyrone, asperpyrone F (1), along with six known ones, asperpyrones B (2) and C (3), fonsecinones A (4) and B (5), aurasperones A (6) and E (7), have been isolated from the solid culture of the edible fungus Pleurotus ostreatus. The structures of 1–7 were determined mainly by NMR and MS experiments. The absolute configuration of compound 1 was assigned via the circular dichroism (CD) data analysis. Compounds 1–7 showed modest antioxidant and immunomodulatory activities. All compounds were isolated from the fungus P. ostreatus for the first time.

Degradation of aflatoxin B1 from naturally contaminated maize using the edible fungus Pleurotus ostreatus

Aflatoxins are highly carcinogenic secondary metabolites that can contaminate approximately 25% of crops and that cause or exacerbate multiple adverse health conditions, especially in Sub-Saharan Africa and South and Southeast Asia. Regulation and decontamination of aflatoxins in high exposure areas is lacking. Biological detoxification methods are promising because they are assumed to be cheaper and more environmentally friendly compared to chemical alternatives. White-rot fungi produce non-specific enzymes that are known to degrade aflatoxin in in situ and ex situ experiments. The aims of this study were to (1) decontaminate aflatoxin B1 (AFB1) in naturally contaminated maize with the edible, white-rot fungus Pleurotus ostreatus (oyster mushroom) using a solid-state fermentation system that followed standard cultivation techniques, and to (2) and to assess the risk of mutagenicity in the resulting breakdown products and mushrooms. Vegetative growth and yield characteristics of P. ostreatus were not inhibited by the presence of AFB1. AFB1 was degraded by up to 94% by the Blue strain. No aflatoxin could be detected in P. ostreatus mushrooms produced from AFB1-contaminated maize. Moreover, the mutagenicity of breakdown products from the maize substrate, and reversion of breakdown products to the parent compound, were minimal. These results suggest that P. ostreatus significantly degrades AFB1 in naturally contaminated maize under standard cultivation techniques to levels that are acceptable for some livestock fodder, and that using P. ostreatus to bioconvert crops into mushrooms can reduce AFB1-related losses.

In Situ Production of Biofunctionalized Few‐Layer Defect‐Free Microsheets of Graphene

Biological interfacing of graphene has become crucial to improve its biocompatibility, dispersability, and selectivity. However, biofunctionalization of graphene without yielding defects in its sp2‐carbon lattice is a major challenge. Here, a process is set out for biofunctionalized defect‐free graphene synthesis through the liquid phase ultrasonic exfoliation of raw graphitic material assisted by the self‐assembling fungal hydrophobin Vmh2. This protein (extracted from the edible fungus Pleurotus ostreatus) is endowed with peculiar physicochemical properties, exceptional stability, and versatility. The unique properties of Vmh2 and, above all, its superior hydrophobicity, and stability allow to obtain a highly concentrated (≈440–510 μg mL−1) and stable exfoliated material (ζ‐potential, +40/+70 mV). In addition controlled centrifugation enables the selection of biofunctionalized few‐layer defect‐free micrographene flakes, as assessed by Raman spectroscopy, atomic force microscopy, scanning electron microscopy, and electrophoretic mobility. This biofunctionalized product represents a high value added material for the emerging applications of graphene in the biotechnological field such as sensing, nanomedicine, and bioelectronics technologies.

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 7.47g/L, and the maximum laccase activity is increased by 15% up to 2,277U/L. Glucose consumption was also found to be relatively faster. The power consumption is 2.8% lower than that of the Rushton turbine.

Polluting macrophytes Colombian lake Fúquene used as substrate by edible fungus Pleurotus ostreatus

Invasive aquatic plants from Lake Fúquene (Cundinamarca, Colombia), water hyacinth (Eichhornia crassipes C. Mart.) and Brazilian elodea (Egeria densa Planch.) have been removed mechanically from the lake and can be used for edible mushrooms production. The growth of the oyster mushroom (Pleurotus ostreatus) on these aquatic macrophytes was investigated in order to evaluate the possible use of fruiting bodies and spent biomass in food production for human and animal nutrition, respectively. Treatments included: water hyacinth, Brazilian elodea, sawdust, rice hulls and their combinations, inoculated with P. ostreatus at 3%. Water hyacinth mixed with sawdust stimulated significantly fruiting bodies production (P = 3.3 × 10(-7)) with 71% biological efficacy, followed by water hyacinth with rice husk (55%) and elodea with rice husk (48%), all of these have protein contents between 26 and 47%. Loss of lignin (0.9-21.6%), cellulose (3.7-58.3%) and hemicellulose (1.9-53.8%) and increment in vitro digestibility (16.7-139.3%) and reducing sugars (73.4-838.4%) were observed in most treatments. Treatments spent biomass presented Relative Forage Values (RFV) from 46.1 to 232.4%. The results demonstrated the fungus degrading ability and its potential use in aquatic macrophytes conversion biomass into digestible ruminant feed as added value to the fruiting bodies production for human nutrition.

The use of spectral mapping for the study of the enzyme production of the edible mushroom Pleurotus Ostreatus

The effect of the addition of extracts of agro-industrial wastes to the culture media on the production of s-glucosidase, xylanase, laccase, manganese-dependent and independent peroxidases by the edible fungus Pleurotus ostreatus was determined. The relationship between cultivation parameters and the enzyme activities was assessed by spectral mapping technique combined with non-linear mapping. It was proved that extracts enhanced markedly the activities of laccase, manganese-dependent and independent peroxidases. Multivariate mathematical-statistical methods indicated that the enzyme activities were the highest in culture containing pepper extract. It was further demonstrated that the selectivity of the enzyme production was negligible up till 14 days of fermentation and reached the maximum at the 28 th day.

Enzyme Production of Pleurotus ostreatus Evaluated by the Three‐Way Principal Component Analysis

AbstractThe effect of the composition of culture media and fermentation time on the production of β‐glucosidase, xylanase, laccase, manganese‐dependent and independent peroxidases by the edible fungus Pleurotus ostreatus was determined. Culture medium separately containing potato, pepper, and tomato extracts and the enzyme activities were assessed to 31.5 days of fermentation. Three‐dimensional principal component analysis (3D‐PCA) followed by the plots of the first two elements of component matrices was employed for the elucidation of the similarities and dissimilarities between the parameters. It was established that the dimensionality of the original 3D matrix (9, 5, 4) could be reduced to 2, 1, 2 with 4.54 % loss of information. The plots demonstrated that the culture media displayed large differences in their capacity to promote enzyme production and that the presence of pepper and tomato extracts exerted the greatest influence on the enzyme activities. The effect of the fermentation time was manifested only after 14 d of fermentation and the highest differences were observed after 28 and 31.5 d of fermentation. Except laccase and manganese‐dependent peroxidase, the enzyme activities also differed considerably dependent on the composition of the fermentation broth. 3D‐PCA followed by the plots of component matrices is a valuable tool for the simultaneous assessment of three dimensional data matrices in biotechnological processes.

Effect of tributylphenyltetraethoxylate on enzyme production of Pleurotus ostreatus.

The effect of the addition of the nonionic surfactant tributylphenyltetraethoxylate to culture media on pH and extracellular protein content, and on production of beta-glucosidase, xylanase, laccase, and manganese-dependent and -independent peroxidases by the edible fungus Pleurotus ostreatus was determined. The relationship between fermentation parameters and concentration of surfactant was assessed by multiple linear regression analysis, and the similarities and differences among the fermentation parameters were elucidated by principal component analysis. Calculations proved that except for xylanase all other cultivation parameters were significantly influenced by the surfactant, with the effect higher at higher surfactant concentrations. Surfactant increased the production of beta-glucosidase and inhibited laccase and manganese-dependent and -independent peroxidase activities.

Growth promotion of the edible fungus Pleurotus ostreatus by fluorescent pseudomonads

Bacteria were isolated from the mycelial surface of Pleurotus ostreatus and their role in fruiting body induction (fructification) of the edible mushroom P. ostreatus was investigated. Analysis of the bacterial community that colonized the mycelium showed that the species composition and numbers of culturable bacteria differed according to the developmental stage of P. ostreatus. In particular, the population size of fluorescent pseudomonads increased during fruiting body induction. An experiment showed that inoculation of pure cultures of the mycelium with strains of fluorescent Pseudomonas spp. isolated from the mycelial plane of commercially produced mushrooms promoted the formation of primordia and enhanced the development of the basidiome of P. ostreatus. Results of this research strongly suggest that inoculation of the mycelium with specific bacteria may have beneficial applications for mushroom production.

Differentially regulated, vegetative-mycelium-specific hydrophobins of the edible basidiomycete Pleurotus ostreatus.

Three different hydrophobins (Vmh1, Vmh2, and Vmh3) were isolated from monokaryotic and dikaryotic vegetative cultures of the edible fungus Pleurotus ostreatus. Their corresponding genes have a number of introns different from those of other P. ostreatus hydrophobins previously described. Two genes (vmh1 and vmh2) were expressed only at the vegetative stage, whereas vmh3 expression was also found in the fruit bodies. Furthermore, the expression of the three hydrophobins varied significantly with culture time and nutritional conditions. The three genes were mapped in the genomic linkage map of P. ostreatus, and evidence is presented for the allelic nature of vmh2 and POH3 and for the different locations of the genes coding for the glycosylated hydrophobins Vmh3 and POH2. The glycosylated nature of Vmh3 and its expression during vegetative growth and in fruit bodies suggest that it should play a role in development similar to that proposed for SC3 in Schizophyllum commune.

Relationship between monokaryotic growth rate and mating type in the edible basidiomycete Pleurotus ostreatus.

The edible fungus Pleurotus ostreatus (oyster mushroom) is an industrially produced heterothallic homobasidiomycete whose mating is controlled by a bifactorial tetrapolar genetic system. Two mating loci (matA and matB) control different steps of hyphal fusion, nuclear migration, and nuclear sorting during the onset and progress of the dikaryotic growth. Previous studies have shown that the segregation of the alleles present at the matB locus differs from that expected for a single locus because (i) new nonparental B alleles appeared in the progeny and (ii) there was a distortion in the segregation of the genomic regions close to this mating locus. In this study, we pursued these observations by using a genetic approach based on the identification of molecular markers linked to the matB locus that allowed us to dissect it into two genetically linked subunits (matBalpha and matBbeta) and to correlate the presence of specific matBalpha and matA alleles with differences in monokaryotic growth rate. The availability of these molecular markers and the mating type dependence of growth rate in monokaryons can be helpful for marker-assisted selection of fast-growing monokaryons to be used in the construction of dikaryons able to colonize the substrate faster than the competitors responsible for reductions in the industrial yield of this fungus.