Pleurotus Tuber-regium Research Articles

Bioremediation of crude oil polluted soil by the white rot fungus, Pleurotus tuberregium (Fr.) Sing.

Bioremediation has become an attractive alternative to physicochemical methods of remediation of polluted sites. White rot fungi (WRF) are increasingly being investigated and used in bioremediation, because of their ability to degrade an extremely diverse range of very persistent or toxic environmental pollutants. The white rot fungus, Pleurotus tuberregium, was examined for its ability to ameliorate crude oil polluted soil. This was inferred from the ability of the polluted soil to support seed germination and seedling growth in Vigna unguiculata, at 0, 7 and 14 days post treatment. Results obtained from the present study showed that bioremediation of soil contaminated with crude oil was possible, especially when the fungus had been allowed to establish and fully colonize the substrate mixed with the soil. There were significant improvements in % germination, plant height and root elongation values of test plants, when seeds were planted 14 days post soil treatment. At 1 to 5% crude oil pollution, % germination values were comparable with the values in control plants in the 14 days treatment, and significantly higher than values obtained in the day 0 treatment. Also, at the highest level of crude oil pollution (15%), there was about 25% improvement in % germination value over the 0 day treatment. This trend of improvement in values was also observed for plant height, root elongation and biomass accumulation as well as decreased total hydrocarbon content.

Studies on submerged fermentation of Pleurotus tuber-regium (Fr.) Singer—Part 1: physical and chemical factors affecting the rate of mycelial growth and bioconversion efficiency

Submerged fermentation of the mycelium of Pleurotus tuber-regium was investigated by studying the physical parameters including the amount of inoculum and duration of fermentation as well as different chemical factors including the carbon and nitrogen sources. The fermentation conditions was set at an orbital shaking of 200±10 rpm at 30±1 °C with a basal medium containing 30 g fructose, 2 g peptone, 2 g yeast extract, 1 g KH2PO4, 0.6 g MgSO4.7H2O per 1 l of distilled water. The amount of mycelial inoculum was set at 10 ml/l of medium. Growth of mycelium using glucose and fructose had a relatively shorter lag phase than that of maize starch with maximum growth on different periods of fermentation. Nitrogen utilization of yeast extract was better than that of peptone when monosaccharide was used as the sole carbon source. Maximum bioconversion efficiency found was about 40%, which was much higher than those reported previously for P. tuber-regium. In the scale-up fermentation, basal medium with fructose gave higher mycelial yield than that of glucose.

Amylolytic studies of pleurotus tuber-regium

The alpha amylase of the sclerotium of Pleurotus tuber-regium was studied. The enzyme was purified from the fresh sclerotium through dialysis, ammonium sulphate fractionation and column chromatography of CM sephadex. The enzyme showed 70% of it's optimal activity between p.H 4.0 to 8.0. Acid and thermal stability was found at p.H 2.0 and temperature of 600c respectively. Michealis Menton constant (km) and maximum velocity (Vmax) of the enzyme with starch as substrate was 1.25mg/ml and 5.0ug/ml/min, respectively. The paper chromatography of the hydrolytic products in starch showed hydrolytic products like glucose, maltose and dextrin, suggesting an alpha-amylase type of activity. Maltose is not hydrolysed by this enzyme. Keywords: Pleurotus tuber-regium, Amylase, Sclerotium, fungus. (Global Journal of Pure and Applied Sciences: 2002 9(1): 53-58)

Proximate composition and functional properties of Pleurotus tuberregium sclerotia flour and protein concentrate

The proximate composition and functional properties of flour and protein concentrate (PC) prepared from Pleurotus tuberregium sclerotia were evaluated. Proximate analysis showed that protein concentration of P. tuberregium flour resulted in an increase of protein from 17.6 to 40.9%. Fat, ash, fiber and carbohydrate contents of the PC were significantly lower than those of the flour. Oil and water absorption capacities of the P. tuberregium flour were 30.0 and 337%, respectively; those of the PC were 55.3 and 331%, respectively. The protein concentrate had higher emulsion activity and stability, but lower bulk density and water absorption capacity than the flour. These results suggest that P. tuberregium flour and PC could serve as useful protein supplements and functional ingredients in formulated foods. However, both the flour and protein concentrate need to be evaluated for antinutritional properties.

Molecular mass and chain conformation of carboxymethylated derivatives of beta-glucan from sclerotia of Pleurotus tuber-regium.

Seven water-insoluble (1 --> 3)-beta-D-glucan fractions TM8-1 to TM8-7 with weight-average molecular mass M(w) ranged from 2.22 to 77.4 x 10(4) obtained from the sclerotia of Pleurotus tuber-regium were carboxymethylated to produce the water-soluble fractions CTM8-1 to CTM8-7 with M(w) ranged from 3.87 to 87.8 x 10(4). The degree of substitution (DS) of CTM8 fractions was analyzed by ir and elemental analysis (EA) to be 0.3-0.68. The M(w) and the intrinsic viscosity [eta] of the CTM8 fractions were measured by size-exclusion chromatography combined with multiangle laser light scattering (SEC-MALLS), MALLS, and viscometry in phosphate buffer solution (PBS) at 37 degrees C. The dependencies of [eta] and radius of gyration <s(2)>(z) (1/2) on M(w) for the CTM8 samples were found to be [eta] = (8.82 +/- 0.03) x 10(-3) M(w)(0.78 +/- 0.04) (cm(3) g(-1)) and <s(2)>(z) (1/2) = (3.09 +/- 0.05) x 10(-3) M(w)(0.75 +/- 0.06) (nm) in the M(w) range from 3.87 x 10(4) to 53.2 x 10(4). Based on current theories for wormlike chain model, the conformational parameters of the CTM8 were obtained to be 790 (nm(-1)) for M(L), 9.6 (nm) for q, which were higher than those of the native TM8 fractions, suggesting a more extended flexible chain of CTM8 in PBS. On the whole, the CTM8 fractions showed higher antitumor activity than their corresponding TM8 fractions. In view of data from molecular parameters and bioactivity, the antitumor activity of the CTM8 fractions may be correlated to its water solubility and relatively extended chain.

A novel and potent ribonuclease from fruiting bodies of the mushroom Pleurotus pulmonarius

A ribonuclease (RNase), with an N-terminal sequence different from those of ribonucleases from the mushrooms Irpex lacteus, Lentinus edodes, Pleurotus ostreatus, Pleurotus tuber-regium, and Volvariella volvacea, was purified from fruiting bodies of the edible mushroom Pleurotus pulmonarius. The N-terminal sequence of P. pulmonarius RNase manifested homology to a portion of the sequences of ribosome inactivating protein abrin-b, abrin-c, and abrin-d, and Bacillus subtilis transcriptional regulator. The ribonuclease was adsorbed on Affi-gel blue gel, CM-Sepharose, and Mono S. It displayed a molecular mass of 14.4 kDa in both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration on Superdex 75. The ribonuclease exhibited an activity of 25 114 U/mg on yeast tRNA. The highest ribonucleolytic activity was demonstrated toward poly C, followed by poly A, and then by poly G. There was no activity toward poly U. The optimal pH for its activity was 7 and the optimal temperature was 55 °C. It inhibited cell-free translation in a rabbit reticulocyte lysate with an IC 50 of 0.33 nM.

Preliminary investigation into the use of Pleurotus tuber-regium powder as a tablet disintegrant

Some physical characteristics of the powder obtained from the mycelia of a giant edible mushroom, Pleurotus tuber-regium, has been determined. Its disintegrant ability in comparison with maize starch BP was also investigated in paracetamol tablets prepared via the wet granulation method. The results obtained showed that P. tuber-regium and maize starch BP have similar true, bulk and tapped density values. The Pleurotus powder however, showed superior flow, swelling capacity as well as water retention capacity to maize starch BP. The swelling capacity was three times that of maize starch BP Tablets prepared with P. tuber-regium powder disintegrated faster than those prepared with maize starch BP at concentrations below 10% w/w. At the disintegrant concentration of 10% w/w paracetamol tablets made from both Pleurotus powder and maize starch BP had similar disintegration times and dissolution profiles. It is believed that the ability of Pleurotus powder to swell by over three times its volume in the presence of water may explain its disintegrant ability. Pleurotus tuber-regium powder may therefore be used as an alternative to maize starch BP as a disintegrant in tableting. Key words: Pleurotus tuber-regium, physical characteristics, paracetamol Trop J Pharm Res, June 2002; 1(1): 29-37

Isolation of Pleuturegin, a Novel Ribosome-Inactivating Protein from Fresh Sclerotia of the Edible Mushroom Pleurotus tuber-regium

A ribosome-inactivating protein (RIP) designated pleuturegin, which inhibited translation in a cell-free rabbit reticulocyte lysate system with an IC50 of 0.5 nM, was purified from fresh sclerotia of the edible mushroom Pleurotus tuber-regium. Pleuturegin was distinguished from most plant and previously reported mushroom RIPs in that it was adsorbed on DEAE-cellulose and unadsorbed on SP-Sepharose, although all of them were adsorbed on Affi-gel blue gel. Pleuturegin demonstrated an N-terminal sequence that was different from those of RIPs from Flammulina velutipes (flammulin and velutin), Hypsizygus marmoreus (hypsin), and Lyophyllum shimeji (lyophyllin), the only mushroom RIPs with known N-terminal sequences. The molecular mass of pleuturegin was 38 kDa, similar to that of flammulin (40 kDa) but considerably larger than those of velutin (13.8 kDa), hypsin (20 kDa), and lyophyllin (20 kDa). Pleuturegin was devoid of ribonuclease activity.

Evaluation of mushroom dietary fiber (nonstarch polysaccharides) from sclerotia of Pleurotus tuber-regium (Fries) singer as a potential antitumor agent.

Mushroom dietary fiber or nonstarch polysaccharides (NSPs) that were soluble in hot alkali and belonged to the beta-glucan type were isolated from the sclerotia of an edible mushroom, Pleurotus tuber-regium. The mushroom NSPs were further separated into a number of fractions [hot alkali extracts (HAEs)] with weight-average molecular weights (M(w)) ranging from 1 x 10(4) to 42.2 x 10(4). The HAE fractions [with M(w) of (5.8-17.1) x 10(4)] administered intraperitoneally at a dose of 20 mg/kg of body weight to BALB/c mice implanted with solid tumor Sarcoma 180 were found to be effective in inhibiting tumor proliferation with an inhibition ratio of > or =50%. In vitro experiments using human tumor cell lines HL-60 and HepG2 had shown that HAE fractions with M(w) of (5.8-42.2) x 10(4) also had antiproliferative activity at three different concentrations (50, 100, and 200 microg/mL) toward the tumor cell lines tested. All HAE fractions did not inhibit the growth of a normal kidney cell line (Vero) from monkey. It is therefore postulated that the antitumoral effect of NSPs from the sclerotia of P. tuber-regium is probably host-mediated and cytocidal.

Purification and characterization of a potent homodimeric guanine-specific ribonuclease from fresh mushroom ( Pleurotus tuber-regium) sclerotia

From the fresh sclerotia of the mushroom Pleurotus tuber-regium, a potent homodimeric ribonuclease exhibiting a molecular weight of 29 kDa in FPLC-gel filtration and sodium dodecyl sulfate–polyacrylamide gel electrophoresis was isolated. The protein was unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel, CM-cellulose and Mono S. It manifested strong ribonucleolytic activity toward Poly G, slight activity toward Poly U and Poly A, and minimal activity toward Poly C. Its optimal pH was determined to be 6.5 when yeast transfer RNA was used as substrate. Its ribonucleolytic activity was resistant to heating at 100°C for 30 min but was inhibited by a number of salts. The protein inhibited cell-free translation in a rabbit reticulocyte lysate with an IC 50 of 0.09 nM. Three out of the four amino acid residues at the active site (positions 38–41) of P. ostreatus ribonuclease, YNNF, were also found at positions 17–20 in the P. tuber-regum RNase. However, unlike P. ostreatus RNase, no cysteine residues were detected in the N-terminal sequence.

Chemical structure and chain conformation of the water-insoluble glucan isolated from Pleurotus tuber-regium.

A water-insoluble polysaccharide (TM8) was isolated from sclerotium of Pleurotus tuber-regium by extraction with 0.5M NaOH aqueous solutions at 120 degrees C. Its chemical structure was confirmed by infrared, high performance liquid chromatography, gas chromatography, and (13)C NMR in dimethylsulfoxide (DMSO) to be composed of beta-(1 --> 3)-D-glucan backbone chain linked with a branched glucose, one out of every three glycosyl units being substituted at C6 position. The glucan TM8 in DMSO was fractionated by nonsolvent addition method into ten fractions, and the solution properties were studied by size exclusion chromatography combined with multiangle laser light scattering (SEC-MALLS) and viscometry in DMSO at 30 degrees C. The dependencies of intrinsic viscosity [eta] and radius of gyration [(s(2)(1/2)(z-2)] on weight-average molecular mass M(w) for this glucan were found to be [eta] = (9.24 +/- 0.2) x 10(-2)M(w)(0.51 +/- 0.02) (cm(3)g(-1)) and [(s(2)(1/2)(z-2)] = (3.67 +/- 0.3) x 10(-2)M(w)(0.56 +/- 0.02) (nm) in the range of M(w) from 1.07 x 10(4) to 77.4 x 10(4). Based on current theories for a wormlike chain, the conformational parameters of the glucan TM8 were found to be 408 (nm(-1)) for M(L), 3.1 (nm) for q, and 16.8 for C(infinity), suggesting that the polysaccharide exists as a dense random-coil chain in DMSO, due to branched structure.

Cultivation of a Selected "Sporophore Only" Producing Strain of the Edible and Medicinal Mushroom Pleurotus tuberregium (Fr.) Sing. on Waste Paper and Plantain Peelings

Cultivation of a Selected "Sporophore Only" Producing Strain of the Edible and Medicinal Mushroom Pleurotus tuberregium (Fr.) Sing. on Waste Paper and Plantain Peelings

A β- d-glucan from the sclerotia of Pleurotus tuber- regium (Fr.) Sing

An alkali-soluble polysaccharide (Hunai polysaccharide, 1) from the fruit body of Pleurotus tuber-regium (Fr.) Sing was shown to be homogeneous by gel permeation chromatography and its molecular weight was ∼4.3×10 5. Complete acid hydrolysis, periodate oxidation, Smith degradation, methylation, FT-IR and 13C NMR analysis, complex formation with Congo Red, indicated that 1 has a β-(1→3)-linked d-glucopyranosyl backbone with a single β- d-glucopyranosyl group at O-6 of every third glucose residue.

Fractionation and characterization of mushroom dietary fiber (nonstarch polysaccharides) as potential nutraceuticals from sclerotia of Pleurotus tuber-regium (Fries) singer.

The nonstarch polysaccharides (NSPs) in the total dietary fiber (TDF) from the sclerotia of Pleurotus tuber-regium (tiger milk mushroom) were fractionated by the sequential use of chemical solvents. About half of the TDF was solubilized and two major alkali-soluble fractions (1 and 4 N sodium hydroxide) that contained 126 and 293 g/kg TDF were obtained. Sugar analysis and infrared spectroscopy indicated that the NSPs in these alkali-soluble fractions were mainly beta-glucans and chitin. These alkali-soluble NSPs were further purified by anion-exchange chromatography followed by gel permeation chromatographic separation. Methylation analysis revealed that these purified glucans were highly branched and contained a mixture of sugar linkages of beta-1,3, beta-1,6, and beta-1,4. The potential use of these sclerotial beta-glucans as nutraceuticals was discussed.

Mating compatibility and phylogeography in Pleurotus tuberregium

Genetic relationships were investigated among several populations of Pleurotus tuberregium from Nigeria, Papua New Guinea and New Caledonia. Intrastock mating compatibility studies using progeny from two collections demonstrated a tetrapolar mating system for P. tuberregium. Interstock matings among the geographically distinct populations were compatible. All isolates were found to be intersterile with tester strains of other Pleurotus species, showing that P. tuberregium represents a unique intersterility group in Pleurotus. Nucleotide sequences of the ITS region of the rDNA gene were determined for 30 isolates and used to infer phylogenetic structure of populations. Phylogenetic analysis shows that African and Australasian-Pacific isolates form at least two distinct evolutionary lineages. Higher genetic divergence was observed among ITS sequences from the Australasian-Pacific region than among African isolates, which suggests a possible origin of P. tuberregium in the Australasian-Pacific region.

Cultivation studies on wild and hybrid strains of Pleurotus tuberregium (Fr.) Sing. on wheat straw substrate

Wild of strains Pleurotus tuberregium from Nigeria and the Australasian-Pacific regions and selected hybrids were studied to determine their growth and sclerotia production capacity on wheat straw substrate. Although the Australasian-Pacific strains showed faster growth rates, the wild strains from Nigeria performed better than the Australasian-Pacific strains in sclerotia yield. Under similar conditions, some hybrids had sclerotial yields that were higher than any wild strain. Our study showed the possibilities of using selected strains and the low cost methods adopted in this experiment, for the cultivation of sclerotia of P. tuberregium.

Effect of three strains of Pleurotus tuber-regium (Fr.) Sing. on chemical composition and rumen fermentation of wheat straw.

This study was conducted to investigate changes in in vitro dry matter digestibility (IVDMD) and cell wall constituent degradation in wheat straw treated with 3 strains of the fungus Pleurotus tuber-regium (PT). The incubation of wheat straw for 30 days at 28 degrees C improved IVDMD from 30.3% (UWS-untreated wheat straw) to 47.1% for strain PT1, to 48.5% for PT4, and was unchanged IVDMD-29.9% -for PT5. The growth of fungi was accompanied by the dry matter loss of wheat straw: 31.5% for PT1, 20.9% for PT4, and 4.8% for PT5. Fungal treatment was characterized by increased crude protein and ash contents (%) in all fungi-treated straws and reduced hemicellulose and lignin content. It is evident that enzymes of all 3 PT strains preferentially degraded hemicellulose and lignin over cellulose. Wheat straw treated with PT1 (TWS-PT1), PT4 (TWS-PT4), and PT5 (TWS-PT5) and barley (80% : 20%) were used as the experimental diets at the fermentation in the artificial rumen. UWS with barley (80% : 20%) served as the control diet. The fermentation of experimental diets was accompanied with increased IVDMD and a very low degree of hemicellulose degradation. Total gas and methane productions were similar in all diets. Moreover, total volatile fatty acid (VFA) production (mmol day(-1)), mol % of acetate, propionate, butyrate, isobutyrate, and isovalerate were not influenced during the fermentation of experimental diets. From the stoichiometric relations, production, utilization, and recovery of metabolic hydrogen and organic matter fermented were unchanged. Only the recovery of metabolic hydrogen in TWS-PT5 was significantly increased in comparison to control diet. Total microbial production showed the tendency of lower values in experimental diets, and it was accompanied with a significant decrease of ammonia nitrogen (mg L(-1)). Finally the results showed that the strains of Pleurotus tuber-regium can improve the quality of wheat straw, but the loss of dry matter (DM) (mainly hemicellulose) limits the effective utilization of fungi-treated straw in ruminant digestion.

Preliminary studies on the ligninolytic enzymes produced by the tropical fungus Pleurotus tuber-regium (Fr.) Sing.

Preliminary studies on the ligninolytic enzymes produced by the tropical fungus Pleurotus tuber-regium (Fr.) Sing.

Comparative Chemical Analysis of Fiber Material Prepared by Enzymatic and Chemical Methods from Two Mushrooms (Pleurotus sajor-cajuandPleurotustuber-regium)

The fiber material of Pleurotus sajor-caju (oyster mushroom) and Pleurotus tuber-regium (tiger milk mushroom) was prepared by two protocols: the enzymatic approach based on the Association of Official Analytical Chemists (AOAC) total dietary fiber (TDF) method and the nonenzymatic method based on the cell wall material (CWM) isolation by the sequential use of chemical solvents. The gravimetric yield of the TDF of the two mushrooms obtained by the enzymatic method was higher than that of the CWM prepared according to the chemical method. The chemical method was more effective than the enzymatic one in removing the mushroom protein. However, some polymeric materials (including fiber material) were solubilized in the chemical solvents used to remove protein and starch from the mushroom. The nonstarch polysaccharide content and composition of the mushroom fiber obtained from the above varied depending on the morphology and types of cell wall polysaccharides present in the two Pleurotus species. Keywords: Mushroom; fiber material; Pleurotus; enzyme; chemical solvent

Toxicological screening of seven Nigerian mushrooms

Toxicological studies were carried out on seven Nigerian mushrooms, namely, Chlorophyllum molybditis (Mayer ex. fr.) Masse, Cortinarius melliolens Fries, Lentinus subnudus Berk, Pleurotus tuber-regium (Fries) Singer, Termitomyces robustus (Beeli) Heim, Tricholoma lobayensis Heim and Volvariella esculenta (Mass) Singer. Amatoxin spot test and Chromatographic screening of the mushrooms revealed the absence of amatoxins and phallotoxins. None of the mushroom extracts tested killed the experimental rats. In fact, some of the rats which fed on or were injected intraperitoneally which mushroom extracts showed some significant gain in dry weight. The significance of these findings is discussed in relation to consumption of these mushrooms.