In mushroom cultivation, it is important to be aware of the impact of the growing substrate. This study investigated the cultivation of various oyster mushrooms, including Pleurotus ostreatus, ...Pleurotus citrinopileatus, and Pleurotus djamor, on different types of wood sawdust. Total phenolic content, condensed tannins, antioxidant activity by ferric reducing antioxidant power assay, protein and sensory evaluations were performed in cultivated oyster mushrooms. Wood sawdust of Fagus orientalis (oriental beech), Alnus glutinosa (alder), Castanea sativa (chestnut), and Juglans regia (walnut) were used as substrate for studied mushroom type, separately. Because champignon (Agaricus bisporus) was the most consumed mushroom, it was used as control sample. Methanolic extracts of dried mushrooms were used to measure bioactive characteristics. Pleurotus ostreatus samples cultivated in Alnus glutinosa (alder) sawdust substrate had the highest antioxidant activity. The lowest antioxidant activity values were found in Pleurotus djamor cultivated in Juglans regia (walnut) wood sawdust substrate. The highest protein content was measured in Agaricus bisporus as 13,84 %. The other highest protein concentration was found in Pleurotus ostreatus cultivated in Alnus glutinosa (alder) sawdust substrate, at 13,75 %. The lowest protein concentration belonged to Pleurotus citrinopileatus cultivated in Fagus orientalis (oriental beech) sawdust substrate as 9,86 %. While Agaricus bisporus and Pleurotus ostreatus had the highest overall appreciation score, Pleurotus citrinopileatus had the lowest. It has been observed that the substrate content has an important impact on chemical and sensory properties of the oyster mushrooms. This study provides knowledge on the chemical and sensory characteristics of three different Pleurotus mushroom species cultivated on different composts.
Summary
White‐rot fungi play an important role in the global carbon cycle because they are the species that almost exclusively biodegrade wood lignin in nature. Lignin peroxidases (LiPs), manganese ...peroxidases (MnPs) and versatile peroxidases (VPs) are considered key players in the ligninolytic system. Apart from LiPs, MnPs and VPs, however, only few other factors involved in the ligninolytic system have been investigated using molecular genetics, implying the existence of unidentified elements. By combining classical genetic techniques with next‐generation sequencing technology, they successfully showed an efficient forward genetics approach to identify mutations causing defects in the ligninolytic system of the white‐rot fungus Pleurotus ostreatus. In this study, they identified two genes – chd1 and wtr1 – mutations in which cause an almost complete loss of Mn2+‐dependent peroxidase activity. The chd1 gene encodes a putative chromatin modifier, and wtr1 encodes an agaricomycete‐specific protein with a putative DNA‐binding domain. The chd1‐1 mutation and targeted disruption of wtr1 hamper the ability of P. ostreatus to biodegrade wood lignin. Examination of the effects of the aforementioned mutation and disruption on the expression of certain MnP/VP genes suggests that a complex mechanism underlies the ligninolytic system in P. ostreatus.
Pleurotus ostreatus is the second most cultivated edible mushroom worldwide after Agaricus bisporus. It has economic and ecological values and medicinal properties. Mushroom culture has moved toward ...diversification with the production of other mushrooms. Edible mushrooms are able to colonize and degrade a large variety of lignocellulosic substrates and other wastes which are produced primarily through the activities of the agricultural, forest, and food-processing industries. Particularly, P. ostreatus requires a shorter growth time in comparison to other edible mushrooms. The substrate used for their cultivation does not require sterilization, only pasteurization, which is less expensive. Growing oyster mushrooms convert a high percentage of the substrate to fruiting bodies, increasing profitability. P. ostreatus demands few environmental controls, and their fruiting bodies are not often attacked by diseases and pests, and they can be cultivated in a simple and cheap way. All this makes P. ostreatus cultivation an excellent alternative for production of mushrooms when compared to other mushrooms.
Wastewater contaminated with heavy metals is a world-wide concern. One biological treatment strategy includes filamentous fungi capable of extracellular adsorption and intracellular bioaccumulation. ...Here we report that an acclimated strain of filamentous fungus Pleurotus ostreatus HAU-2 can withstand Pb up to 1500 mg L−1 Pb, conditions in which the wildtype strain cannot grow. The acclimated strain grew in liquid culture under 500 mg L−1 Pb without significant abnormity in biomass and morphology, and was able to remove significant amounts of heavy metals with rate of 99.1% at 200 mg L−1 and 63.3% at 1500 mg L−1. Intracellular bioaccumulation as well as extracellular adsorption both contributed the Pb reduction. Pb induced levels of H2O2, and its concentration reached 72.9–100.9 μmol g−1 under 200–1000 mg L−1 Pb. A relatively higher malonaldehyde (MDA) concentration (8.06–7.59 nmol g−1) was also observed at 500–1500 mg L−1 Pb, indicating that Pb exposure resulted in oxidative damage. The fungal cells also defended against the attack of reactive oxygen species by producing antioxidants. Of the three antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), CAT was the most responsive and the maximal enzyme activity was 15.8 U mg−1 protein. Additionally, glutathione (GSH) might also play a role (3.16–3.21 mg g−1 protein) in detoxification under relatively low Pb concentration (100–200 mg L−1). Our findings suggested that filamentous fungus could be selected for increased tolerance to heavy metals and that CAT and GSH might be important components of this tolerance.
•The tolerance of fungus to Pb was enhanced significantly after acclimatization.•The acclimated strain could accumulate Pb as high as 165.0 mg g−1.•Pb could induce the mycelia to produce malonaldehyde and H2O2.•Catalase and glutathione might play an important role in elimination of the toxicity.
Cultivated oyster mushrooms (genus
Pleurotus) are interesting as a source of biologically active glucans. Partially, β-glucan from
Pleurotus sp. (pleuran) has been used as food supplements due to its ...immunosuppressive activity. Like other dietary fibre components, oyster mushroom polysaccharides can stimulate the growth of colon microorganisms (probiotics), i.e. act as prebiotics. Specific glucans were isolated from stems of
Pleurotus ostreatus and
Pleurotus eryngii by subsequent boiling water and alkali extraction. Obtained water soluble (
L1), alkali soluble (
L2) and insoluble (
S) fractions were characterised by various analytical methods. Spectroscopic analysis detected glucans in all the fractions: branched 1,3-1,6-β-
d-glucan predominated in
L1 and
S, while linear 1,3-α-
d-glucan in
L2. Fractions
L1 also contained marked amount of proteins partially in complex with glucans; protein content in
L2 was insignificant. Effective deproteinisation of
L1 and separation of α- and β-glucans in
L2 was achieved by the treatment with phenolic reagent. Small amount of chitin was found in
S as a component of cell wall chitin–glucan complex. Potential prebiotic activity of extracts
L1 and
L2 was testing using nine probiotic strains of
Lactobacillus,
Bifidobacterium and
Enterococcus. These probiotics showed different growth characteristics dependently on used extract and strain specificity due to the presence of structurally diverse compounds. The extracts
L1 and
L2 can be applied to synbiotic construction only for carefully selected probiotic strains. This exploitation of fruit body extracts extends the use of mushrooms
P. ostreatus and
P. eryngii for human health.
The extraction conditions of intracellular polysaccharide (IPS) from
Pleurotus sp. mycelium in submerged culture were investigated. Four parameters affecting the IPS extraction, ultrasonic treatment ...time, extraction temperature, extraction time and ethanol concentration, were determined by single factor tests and then optimized by orthogonal experiments. Under the optimized conditions, the extraction rates of IPS of
Pleurotus nebrodensis SJ-02,
Pleurotus eryngii SI-01 and
Pleurotus corncopiae SS-01 were 7.1
±
0.4%, 7.5
±
0.3%, and 8.2
±
0.5%, respectively. The
in vitro hydroxyl radical inhibition percentages of IPS of three mushrooms were 32.2
±
2.8%, 16.1
±
1.5%, and 38.7
±
3.1%, respectively. The scavenging effects of IPS on superoxide anion radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical were 19.1
±
1.5%, 16.3
±
1.3%, 20.3
±
1.8%, 17.9
±
1.6%, 16.8
±
1.4%, and 20.5
±
1.7%, respectively. The results provide a reference for large-scale production of IPS by
Pleurotus sp. in industrial fermentation.
► Pleurotus florida cultivated on Se-rich wheat straw efficiently accumulated Se. ► The Se in mushrooms was largely bioaccessible. ► The bioaccessible Se was mainly present as selenomethionine. ► ...Producing Se-biofortified mushrooms using Se-rich agricultural-residues is feasible.
Cultivation of saprophytic fungi on selenium-rich substrates can be an effective means to produce selenium-fortified food. Pleurotus florida, an edible species of oyster mushrooms, was grown on wheat straw from the seleniferous belt of Punjab (India) and its potential to mobilize and accumulate selenium from the growth substrate was studied. Selenium concentration in biofortified mushrooms was 800 times higher compared with control samples grown on wheat straw from non selenium-rich areas (141 vs 0.17μgSeg−1 dry weight). Seventy-five percent of the selenium was extracted after in vitro simulated gastrointestinal digestion and investigation of the selenium molecular fractions by size exclusion HPLC-ICP-MS revealed that proteins and any other high molecular weight selenium-containing molecule were hydrolyzed to peptides and low molecular weight selenocompounds. Analysis of the gastrointestinal hydrolysates by anion exchange HPLC-ICP-MS showed that the bioaccessible selenium was mainly present as selenomethionine, a good bioavailable source of selenium, which accounted for 73% of the sum of the detected species.
This study demonstrates the feasibility of producing selenium-biofortified edible mushrooms using selenium-rich agricultural by-products as growth substrates. The proposed approach can be used to evaluate whether selenium-contaminated plant waste materials harvested from high-selenium areas may be used to produce selenium-biofortified edible mushrooms based on the concentration, bioaccessibility and speciation of selenium in the mushrooms.
This study aimed to evaluate the effect of cultivation conditions in the context of light on the retention of selected vitamins, minerals and polyphenols in the stem and cap of the oyster mushroom ...(Pleurotus ostreatus L.). Additionally, the effect of the retention of bioactive components on the antioxidant activity of mushroom extracts was evaluated, taking into account the morphological part. Oyster mushrooms grown in the light of 200 lux had higher riboflavin content compared to mushrooms exposed to the light of lower intensity. The thiamine content of the mushrooms dropped with decreasing light intensity during cultivation. The content of biologically active compounds was found to be equal in the stem and the cap. In the case of riboflavin, it was shown that its contents in cap fractions, irrespective of the cultivation method, was statistically significantly higher than in stems. The mineral composition of caps and stems differed from each other. No differences in Zn and Cu content between the morphological parts of the mushroom studied were found. However, it was shown that the stems, regardless of the type of light, contained less iron, magnesium and sodium. Thus, it was observed that limited light exposure caused an increase in the content of total polyphenolic compounds, which did not correlate with antioxidant activity. There was no effect of the light on the antioxidant activity of mushrooms. It was also shown that stem extracts had higher antioxidant activity compared to the extracts obtained from the caps. This findings point to the possibility and potentail of use both fraction of mushrooms in the new food products development.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Fungi interact with their environment by secreting proteins to obtain nutrients, elicit responses and modify their surroundings. Because the set of proteins secreted by a fungus is related to ...its lifestyle, it should be possible to use it as a tool to predict fungal lifestyle. To test this hypothesis, we bioinformatically identified 538 and 554 secretable proteins in the monokaryotic strains PC9 and PC15 of the white rot basidiomycete Pleurotus ostreatus. Functional annotation revealed unknown functions (37.2%), glycosyl hydrolases (26.5%) and redox enzymes (11.5%) as the main groups in the two strains. When these results were combined with RNA‐seq analyses, we found that the relative importance of each group was different in different strains and culture conditions and the relevance of the unknown function proteins was enhanced. Only a few genes were actively expressed in a given culture condition in expanded multigene families, suggesting that family expansi on could increase adaptive opportunities rather than activity under a specific culture condition. Finally, we used the set of P. ostreatus secreted proteins as a query to search their counterparts in other fungal genomes and found that the secretome profiles cluster the tested basidiomycetes into lifestyle rather than phylogenetic groups.
Mushrooms of the genus Pleurotus are comprised of cultivated edible ligninolytic fungi with medicinal properties and a wide array of biotechnological and environmental applications. Like other ...white-rot fungi (WRF), they are able to grow on a variety of lignocellulosic biomass substrates and degrade both natural and anthropogenic aromatic compounds. This is due to the presence of the non-specific oxidative enzymatic systems, which are mainly consisted of lacasses, versatile peroxidases (VPs), and short manganese peroxidases (short-MnPs). Additional, less studied, peroxidase are dye-decolorizing peroxidases (DyPs) and heme-thiolate peroxidases (HTPs). During the past two decades, substantial information has accumulated concerning the biochemistry, structure and function of the Pleurotus ligninolytic peroxidases, which are considered to play a key role in many biodegradation processes. The production of these enzymes is dependent on growth media composition, pH, and temperature as well as the growth phase of the fungus. Mn²⁺concentration differentially affects the expression of the different genes. It also severs as a preferred substrate for these preoxidases. Recently, sequencing of the Pleurotus ostreatus genome was completed, and a comprehensive picture of the ligninolytic peroxidase gene family, consisting of three VPs and six short-MnPs, has been established. Similar enzymes were also discovered and studied in other Pleurotus species. In addition, progress has been made in the development of molecular tools for targeted gene replacement, RNAi-based gene silencing and overexpression of genes of interest. These advances increase the fundamental understanding of the ligninolytic system and provide the opportunity for harnessing the unique attributes of these WRF for applied purposes.
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