ofPleurotus Ostreatus Research Articles

Effect of Five Concentrations of Aqueous Extracts of Pleurotus ostreatus P. Kumm and Tagetes minuta L. on the Mortality of Two Nematodes in a Laboratory Setting.

The nematode attacks affect several plant species of Ecuadorian crops. Fungi and plants with nematicide ability are of agricultural interest. This study assessed the effect of five concentrations of aqueous extracts of Pleurotus ostreatus and Tagetes minuta on the mortality of Meloidogyne spp. and Panagrellus redivivus nematodes in a laboratory setting. The aqueous extracts were obtained through hydro distillation where concentrations of 0%, 0.5%, 5%, 25%, 50% and 100% were prepared. A wholly randomized single-factor design was used for the P. ostreatus extract and a bifactorial for the T. minuta extract (leaves and flowers). The number of dead individuals was evaluated, and the efficacy and LC50 were determined. T. minuta leaf extract showcased higher nematicide activity against P. redivivus with an LC50 of 8.03 ppm; when applied to Meloidogyne sp., the extract showed nematicide activity with an LC50 of 0.01 ppm. For P. ostreatus extract, the greatest nematicide activity against P. redivivus was an LC50 of 1.22 ppm and nematicide activity against Meloidogyne sp., was an LC50 of 0.01 ppm. The aqueous extract of T. minuta flowers showed low nematicide activity and the aqueous extract of T. minuta leaf showed the best nematicide activity. Keywords: nematicide; Tagetes minuta; Pleurotus ostreatus; Panagrellus redivivus; Meloidogyne sp.

Screening of cellulose- and lignin-degrading fungi for improving nutritive quality of ruminant feed

This experiment aimed to screen some cellulose- and lignin-degrading fungal species for improving nutritive quality of ruminant feed. Fungal species used wereGanoderma lucidum, Pleurotus ostreatus, Phanerochaete chrysosporium, andTrametes visicolor. These fungal species were grown on Potato Dextrose Broth (PDB) medium that added with 0.5 g substrate, i.e. either rice straw, rice bran or carboxymethyl cellulose for 12 days at room temperature. Harvesting was performed in order to separate fungal mycelium and supernatant that contained crude cellulase enzyme. Among the fungi observed,Ganoderma lucidumhad the highest cellulase activity, i.e. 4.02 U/mg. Cellulase activities ofPleurotus ostreatus, Phanerochaete chrysosporium, andTrametes visicolorwere 1.53, 1.08, and 0.13 U/mg, respectively.Ganoderma lucidumwas further investigated for its ligninolytic enzyme activity, i.e. laccase and manganese peroxidase. It was observed that the fungi had laccase and manganese peroxidase activities of 368.95 and 33.89 U/mL, respectively. Crude enzymes ofGanoderma lucidumthat contain cellulase, laccase and manganese peroxidase were further used to increase nutritive quality of rice straw and subjected to in vitro incubation with rumen fluid of cattle.

Identification and Characterization of Small Noncoding RNAs in Genome Sequences of the Edible Fungus Pleurotus ostreatus.

Noncoding RNAs (ncRNAs) have been identified in many fungi. However, no genome-scale identification of ncRNAs has been inventoried for basidiomycetes. In this research, we detected 254 small noncoding RNAs (sncRNAs) in a genome assembly of an isolate (CCEF00389) of Pleurotus ostreatus, which is a widely cultivated edible basidiomycetous fungus worldwide. The identified sncRNAs include snRNAs, snoRNAs, tRNAs, and miRNAs. SnRNA U1 was not found in CCEF00389 genome assembly and some other basidiomycetous genomes by BLASTn. This implies that if snRNA U1 of basidiomycetes exists, it has a sequence that varies significantly from other organisms. By analyzing the distribution of sncRNA loci, we found that snRNAs and most tRNAs (88.6%) were located in pseudo-UTR regions, while miRNAs are commonly found in introns. To analyze the evolutionary conservation of the sncRNAs in P. ostreatus, we aligned all 254 sncRNAs to the genome assemblies of some other Agaricomycotina fungi. The results suggest that most sncRNAs (77.56%) were highly conserved in P. ostreatus, and 20% were conserved in Agaricomycotina fungi. These findings indicate that most sncRNAs of P. ostreatus were not conserved across Agaricomycotina fungi.

Potential of Pleurotus ostreatus mycelium for selenium absorption.

The aim of this study was to evaluate the effect of high selenium (Se) concentrations on morphophysiological and ultrastructural properties of Pleurotus ostreatus. Mycelium growth was good in media enriched with 5.0, 10.0, and 20.0 mg L−1 of Se, concentration of 500.0 mg L−1 strongly inhibited growth, and 1000.0 mg L−1 was the minimum inhibitory concentration. Contrary to thin-walled, hyaline, branched, and anastomized hyphae with clamp-connections in the control, at Se concentrations of 100.0 and 500.0 mg L−1, they were noticeably short, frequently septed and branched, with a more intensive extracellular matrix, and without clamp-connections. At high Se concentrations, hyphae with intact membrane, without cellular contents, with a high level of vacuolization, and with numerous proteinaceous bodies were observed. Biomass yield ranged between 11.8 g L−1, in the control, and 6.8 g L−1, at an Se concentration of 100.0 mg L−1, while no production was detected at a concentration of 500.0 mg L−1. Se content in the mycelia reached a peak (938.9 μg g−1) after cultivation in the medium enriched with Se at the concentration of 20.0 mg L−1, while the highest absorption level (53.25%) was found in the medium enriched with 5.0 mg L−1 Se.

Potential of Oyster Mushrooms for the Biocontrol of Sugar Beet Nematode (Heterodera Schachtii)

Potential of Oyster Mushrooms for the Biocontrol of Sugar Beet Nematode (Heterodera Schachtii)The potential of oyster mushrooms to attack and kill sugar beet cyst nematode (Heterodera schachtii) was studied. The ability ofPleurotus ostreatus, P. sajor-caju, P. florida, P. flabellatus, P. ostreatus(sporeless),P. eryngiiandHypsizygus ulmariusto prey on the cyst nematode was confirmed. Nematodes were inoculated on water agar plates on which a single sparse fungal colony of one of the above mentioned fungi was grown. Nematodes were quickly immobilized after inoculation the plates with eachPleurotusspecies, with mortality of about 96%, 72%, 55%, 52%, 20%, 23% and 62%, respectively. Nematicidal activities of culture filtrates ofPleurotusspecies andH. ulmariusagainstH. schachtiiwere also studiedin vitro.Extracts ofP. ostreatuscould paralyse 90% of nematodes whereasP. eryngiicould paralyse only 50% of nematodes. The efficacy of old mushroom compost from cultures ofP. ostreatusandP. sajor-cajuin controlling cysts on sugar beet (Beta vulgarisICI) were studied under greenhouse conditions. The results showed that 100 and 200 grams of mushroom compost per 3 kilogram/pot could significantly control cysts, reducing more than 85% cysts in soil. Presence of cysts on the roots and larvae inside roots were compared with the control treatment.

Production of lignocellulose-degrading enzymes and changes in soil bacterial communities during the growth ofPleurotus ostreatus in soil with different carbon content

The extracellular enzyme activity and changes in soil bacterial community during the growth of the ligninolytic fungus Pleurotus ostreatus were determined in nonsterile soil with low and high available carbon content. In soil with P. ostreatus, the activity of ligninolytic enzymes laccase and Mn-peroxidase was several orders of magnitude higher than in soil without the fungus. Addition of lignocellulose to soil increased the activity of cellulolytic fungi and the production of Mn-peroxidase by P. ostreatus. The counts of heterotrophic bacteria were more significantly affected by the presence of lignocellulose than by P. ostreatus. The effects of both substrate addition and time (succession) were more significant factors affecting the soil bacterial community than the presence of P. ostreatus. Bacterial community structure was affected by fungal colonization in low carbon soil, where a decrease of diversity and changes in substrate utilization profiles were detected.

Interference of laccase in determination of cellobiose dehydrogenase activity of Pleurotus ostreatus (Florida) using dichlorophenol indophenol as the electron acceptor

Pleurotus ostreatus (Florida), ITCC 3308 produces approximately 9.0 U/ml extracellular cellobiose dehydrogenase (CDH) in cellulose medium after 7 days of growth. However, no activity could be detected if the assay was done with cellobiose as the substrate and 2,6-dichlorophenol indophenol (DPIP) as the electron acceptor in absence of any laccase inhibitor. Kinetic study showed that V(max)/K(m) value was very high for rDPIP (reduced 2,6-dichlrophenol indophenol) oxidation by laccase. Oxygen consumption rate of rDPIP oxidation by the enzyme was found to be highest among all the tested substrates. The present study indicated that rDPIP was a good substrate for laccase. Therefore, caution is needed to measure CDH activity by monitoring DPIP reduction in a system where laccase is likely to be present.

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.

Mycelial yield ofPleurotus ostreatus using thinned apple, pear, and peach on submerged culture

The effect of thinned fruits, apple, pear and peach, on the mycelial growth of mushrooms was investigated. The growth of mycelia with the addition of thinned fruit was clearly better than that in the control for all the tested mushrooms. The growth rate ofPleurotus ostreatus was faster than any other mushroom. The optimal concentrations of thinned apple, pear, and peach in a solid culture were 1.0%, 1.0%, and 3%, respectively, while in a liquid culture the optimal concentrations were 5,0%, 3.0%, and 5.0%, respectively. WhenPleurotus ostreatus was incubated in a 20-L pilot scale fermenter with 10 L of a liquid medium containing 3% thinned fruit at 25°C and 6 vvm for 10 days, the mass-production of mycelia was 74.2 g/10 L (apple), 96.2 g/10 L (pear), and 86.3 g/10 L (peach). The mycelial yield ofPleurotus ostreatus in a medium containing thinned fruit was 2≈3 times higher than that in the control.

Changes in low molecular weight carbohydrates composition and chitin throughout the cultivation stages of Pleurotus ostreatus

Changes in contents of soluble low molecular weight carbohydrates and chitin in a sawdust-rice bran medium during mycelial growth ofPleurotus ostreatus in bottle cultivation were examined in relation to fruit-body yield of nine stocks. Glucose, mannitol, inositol, sucrose, and trehalose were detected in cultures after mycelial spreading. No significant correlation was observed between contents of soluble low molecular weight carbohydrate during mycelial growth and the fruit-body yield. Negative correlation was found between trehalose content in post-harvest cultures and the fruit-body yield. Chitin content in cultures decreased in the fruiting stage. Positive correlation was detected between chitin content of fruit-bodies and the decrement of chitin in post-harvest culture caused by fruit-body growth.

Carbohydrates and lipids ofPleurotus ostreatus

The composition of the fruiting body ofPleurotus ostreatus has been studied. The total neutral lipids and phospholipids have been isolated. In the neutral lipids, free fatty acids, triacylglycerols, and sterol and triterpenol esters predominated. In the phospholipids, the main components were phosphatidylethanolamines and phosphatidylserines. The qualitative compositions of the sugars and the pectin are given.

Promoting effect of wood vinegar compounds on fruit-body formation of Pleurotus ostreatus

The promoting effect of wood vinegar compounds on the fruiting ofPleurotus ostreatus (Japanese name, Hiratake) was investigated. Not only crude wood vinegar but its components, 3,5-dimethylphenol, 2-methoxyphenol, butanoic acid and 1-pentanol, had the ability to promote fruit-body formation on liquid medium. For use of these promoters industrially, a test for practical cultivation was carried out using a commercial sawdust medium. The addition of 100 µg/ml butanoic acid and 100 µg/ml 2-methoxyphenol into the sawdust medium after removal of the surface mycelial layer (kinkaki in Japanese) produced 29 and 23% higher yields of fruit-bodies than the control cultures (137.2 g/bottle), respectively. The addition of the crude wood vinegar as a medium component into sawdust substrates in the concentration range of 0.1–6% increased yields of fruit-bodies by 21–42% over the control.

Oxidation of syringic acid by extracellular peroxidase of white-rot fungus, Pleurotus ostreatus

The oxidative degradation of syringic acid by the extracellular peroxidase ofPleurotus ostreatus was studied. Three products formed in the oxidation of syringic acid by the peroxidase in the presence of O2 and H2O2 were identified as 2,6-dimethoxyphenol, 2,6-dimethoxy-1,4-dihydroxybenzene, and 2,6-dimethoxy-1,4-benzoquinone. A free radical was detected as the reaction intermediate of the extracellular peroxidase-catalyzed oxidation of acetosyringone. These results can be explained by mechanisms involving the production of a phenoxy radical and subsequent decarboxylation. This is the first time that 2,6-dimethoxyphenol has been identified in extracellular peroxidase-catalyzed reactions.

Double-stranded RNA mycoviruses in mycelium ofPleurotus ostreatus

Double-stranded RNA mycoviruses in mycelium of<i>Pleurotus ostreatus</i>

Cultivation of fungi on sugar cane biomass

The possibility of cultivation of fungi on sugar cane waste (leaves and stalk tops) was tested. Having been crushed, macerated and heated, this material becomes a suitable substrate for cultivation of oyster mushrooms. Selected hybrids ofPleurotus ostreatus × P. ostreatus form Florida rapidly colonized the substrate and, in the first phase, yielded more than 10% of fresh fruiting bodies per initial mass of the wet substrate, which is considered, to be the efficiency limit of this technology. The growth cycle in Cuba is shorter than in Europe. Under the tested temperature and light conditions in Cuba, all strains formed white fruiting bodies, as compared to a multicolored variety developed in Czechoslovakia. Some of the newly obtained hybrids were found to have better properties than the original production strains. Hybrids of Cuban origin should be prepared. Besides common, well-known pests, several species of ants damage the cultures of oyster mushrooms.

Peat extract as a carbon source for the growth of Pleurotus ostreatus mycelium

AbstractThe submerged culture of edible mushroom mycelium has been studied because of its potential to produce food, food additives and food supplements. One of the species of edible mushrooms which have been cultivated in submerged culture for the production of mycelial biomass is Pleurotus ostreatus (Zadrazil 1978). The growth of P ostreatus con peat and its mycelium cultivation in peat extracts have also been reported (Manu‐Tawiah and Martin 1986, 1987).

Study of operational variables in the submerged growth ofPleurotus ostreatus mushroom mycelium

Pleurotus ostreatus mushroom mycelium was cultivated in submerged culture in shake-flask experiments with acid extract from peat and yeast extract as nutrient sources. Different concentrations of water-diluted peat extract were tested in an attempt to overcome the effect of growth inhibitors apparently present in nondiluted peat extracts. The best results were obtained with a ratio of one part of peat extract diluted with one part of water. Several operating variables were studied to optimize the growth of mycelial biomass ofP. ostreatus. The best results produced approximately 5 g/L dry biomass with a yield of 60% and an efficiency of 33%. These results were obtained in 8 d at 5% (v/v) inoculum ratio, 28°C, pH of 5.0, and 150 rpm.

Laccase fromPleurotus ostreatus

Laccase was purified from culture broth ofPleurotus ostreatus mycelium. The enzyme was a single protein of Mr 59000, pI 2.9 and was active on o-diphenyl substrates. Amino acid composition and N-terminal sequence (15 residues) were determined. Polyclonal anti-laccase antibodies were obtained.

The effect of citrate on the synthesis of penicillin V-acylase of piiur otus ostreatus

Several cultivation conditions were investigated for their influence on the penicillin V-acylase activity ofPleurotus ostreatus. We found that the conditions for good microbial growth and for the increase of penicillin V-acylase activity respectively were quite different. We here describe a method which allows to get good growth and high penicillin V-acylase activity in spite of this discrepancy. present adress: Institut fur Landwirtschaftliche Technologie und Zuckerindustrie, Langer Kamp 5, 3300 Braunschweig, FRG

Exogenous regulators in the mycelium of Pleurotus ostreatus after exogenous application.

The mycelium of the fungus Pleurotus ostreatus was cultured on a synthetic medium with growth regulators. Best growth was observed on media with 100 ppm IAA, 200 ppm GA3 and 200 ppm of kinetin. Growth of terminal hyphae and the appearance of colonies differed characteristically. Auxin bio-assays showed that the content of substances in younger mycelium slowly increased during cultivation without conspicuous changes in the medium. After exogenous application of IAA the content of auxins in younger mycelium increased and the content of IAA decreased gradually in the culture medium. Gibberellin bio-assays showed their content in the mycelium fell during cultivation and while it increased in the medium. Application of GA3 to the medium leads to a significant increase in these substances in the young mycelium and in the medium their level remains the same. Cytokinin bio-assays showed their content to vary during cultivation. An addition to kinetin to the nutrient medium results in an increase of cytokinins in the mycelium while in the medium the level of cytokinins is maintained. Addition of one substance thus influences the levels of other endogenous regulators.