Solid state fermentation of Saccharum munja residues into food through Pleurotus cultivation

The technical feasibility of using Saccharum munja as a substrate for the cultivation of the oyster mushroom, Pleurotus sajor-caju, is evaluated. The biological efficiency of mushroom production is compared on different substances-S. munja, S. munja plus paddy straw, and paddy straw. Although the efficiency is low on S. munja, the ready availability of this weed large areas holds a favourable option for its use in mushroom cultivation. The crude proteins, fats, carbohydrates, and energy values are also lower though the differences are not great. The degradation of three major components-cellulose, hemicellulose, and lignin has been observed, which proves P. sajor-caju to be a lignocellulolytic fungus. The nitrogen and mineral analysis of post-mushroom production S. munja (spent substrate) compares favorably with the dry cow-feed ration showing an enhanced protein content in the spent substrate.     

Mineral content of the fruiting bodies of Pleurotus sajor-caju (FR.) SINGER cultivated on different kinds of biomass

Pleurotus sajor-caju (FR. ) SINGER was cultivated on different organic wastes, namely sericulture waste, Populus deltoides MARSH , and Eupatorium adenophorum SPRENG . Paddy straw was taken as the control and all the data were compared with it. The mineral contents of the fruiting bodies of Pleurotus sajor-caju and the substrates on which the mushroom was grown were analyzed. Among the eight minerals determined (calcium, phosphorus, potassium, magnesium, sodium, iron, manganese and zinc), the potassium content was highest followed by phosphorus, magnesium and sodium. Analysis of the mineral contents of the substrates before cultivation had also been carried out. The mineral contents of the fruiting bodies of Pleurotus sajor-caju were found to be different on different substrates. It was also observed that the mineral contents of the fruiting bodies of Pleurotus sajor-caju increase when cultivated on substrates with higher mineral contents. The maximum mineral contents per 100 g of the substrates before cultivation were Ca – 347 mg; P – 151 mg; K – 1,805 mg; Na – 127 mg; Mg – 227 mg; Fe – 53 mg; Mn – 10 mg and zn – 3.1 mg. The mineral contents of the fruiting bodies of Pleurotus sajor-caju per 100 g ranged as follows: Ca – 25.1 mg to 35.3 mg; P – 448 mg to 602 mg; K – 2,146 mg to 2350 mg; Na – 139 mg to 229 mg; Mg – 153 mg to 224 mg; Fe – 9.74 mg to 20.75 mg; Mn – 2.5 mg to 4.0 mg and Zn – 2.2 mg to 3.1 mg.     

Protein enrichment and digestibility of soft rush (<Emphasis Type="Italic">Juncus effusus</Emphasis>) and rice residues using edible mushrooms <Emphasis Type="Italic">Pleurotus ostreatus</Emphasis> and <Emphasis Type="Italic">Pleurotus sajor-caju</Emphasis>

Pleurotus species are found to be among the most efficient lignocellulolytic types of white-rot fungi. Rice is the main grain cultivated in the extreme south of Brazil. Defatted rice bran and straw are by-products of low aggregate value. Soft rush (Juncus effusus) is a common native plant also very abundant in the region. In the present work, we evaluated changes in substrate composition after growth of two white-rot fungal species: Pleurotus ostreatus and Pleurotus sajor-caju, aiming to increase protein content and digestibility from substrates through solid fermentations and obtain edible mushrooms of high aggregate value. For that, defatted rice bran, defatted rice straw and soft rush were utilized as substrate. The influence of the variables thermal treatment temperature of substrate, substrate moisture and concentration were evaluated on the protein content, digestibility and biological efficiency. The highest protein enrichment of rice bran in P. sajor-caju-fermented medium was due the fact that there was no fructification in these media, while for the P. ostreatus-fermented medium, part of the synthesized protein was converted into mushrooms. The highest protein enrichments were verified in medium with 80% moisture and 25% soft rush (47.1% using P. ostreatus and 49.0% using P. sajor-caju). A higher digestible protein increase was obtained for both species in media with 70% moisture and 25% soft rush.     

Cultivation of oyster mushrooms on wheat straw and bagasse substrate amended with distillery effluent

Summary Molasses-based distilleries produce large quantities of dark coloured effluent, which is a major cause of environmental pollution. An experiment was conducted to investigate the efficacy of distillery effluent amendment for edible mushroom production. Three species of oyster mushroom, namely Pleurotus florida Eger (EM 1303), Pleurotus pulmonarius (Fries) Quelet (EM 1302) and Pleurotus sajor-caju (Fries) Singer (EM 1304) were grown on wheat straw (variety UP 2338) and bagasse amended with post-anaerobic distillery effluent, a high organic load wastewater with high biochemical oxygen demand and chemical oxygen demand. Three different levels of effluent treatment were applied to bagasse and wheat straw. Wheat straw was found to be the preferred substrate and showed better results than bagasse in all treatments with respect to yield, biological efficiency (BE) and dry matter loss. P. florida (EM 1303) and P. pulmonarius (EM 1302) gave significantly enhanced yield with increasing levels of effluent, with BE reaching highest at 238.6% for P. florida (EM 1303). Using bagasse as a substrate, P. sajor-caju (EM 1304) and P.␣pulmonarius (EM 1302) exhibited a decreasing trend as compared to control. However, the effect of effluent concentrations did not influence yield and BE significantly in case of bagasse. The dry matter loss of the substrate varied from 9.4% to 53.4% in wheat straw and 17.5% to 45.2% in bagasse respectively.     

Growth of higher fungi on wheat straw and their impact on the digestibility of the substrate

Summary The influence of the growth of three higher fungi on the composition of wheat straw was investigated. Pleurotus pulmonarius, P. sajor-caju and Lentinus edodes grew very well on lignocellulosic substrates, breaking down a considerable amount of lignin. The initial lignin concentration of straw was halved after 12 weeks of fungal growth, doubling the enzymic digestibility. Together with lignin, the higher fungi consumed half of the amount of hemicellulose (i.e. 15%), leaving cellulose fairly intact, which should remain as an energy source for ruminants.     

Effect of lignin-derived phenolic monomers on the growth of the edible mushrooms Lentinus edodes,Pleurotus sajor-caju and Volvariella volvacea

Pleurotus sajor-caju was generally more tolerant to lignin-related phenolic monomers and tannin derivatives than Lentinus edodes and the straw mushroom, Volvariella volvacea. Several phenols, at up to 5 mM, enhanced mycelial growth of P. sajor-caju. No clear pattern was evident when the effects of phenols and tannins on the growth of V. volvacea and L. edodes were compared, but the lower concentrations of 4-hydroxybenzaldehyde and vanillin which were tested were markedly more toxic to the straw mushroom. The distribution of phenolic monomers and tannin derivatives in the agricultural wastes used for mushroom cultivation may be an important growth determinant. However, the differences in the growth inhibition profiles of L. edodes, P. sajor-caju and V. volvacea suggest that, alone, the effect of these compounds on fungal growth is unlikely to account for the varying abilities of the three mushroom species to grow and fruit on a particular lignocellulosic substrate.     

Recycling spent larval food of Corcyra cephalonica Stainton for preparing spawn and sporophore of Pleurotus sajor-caju (Fr.) Singer

Large scale production of the rice moth, Corcyra cephalonica Stainton in pearl millet grain medium leads to a huge accumulation of spent larval medium in commercial insectaries. We attempted bioconversion of spent larval medium of C. cephalonica (CLM) for cultivation of the mushroom Pleurotus sajor-caju (Fr.) Singer, to increase the usage of these residues. Maximum efficiency limits of CLM for spawn run, sporophore cropping and as bed substrate were assessed with varying combinations of sorghum and rice straw. Sorghum grains and rice straw were the best substrates for spawn run and sporophore yield respectively. Having been crushed, macerated, heated and sterilized, CLM could also become a suitable substrate along with sorghum or rice straw. Sorghum and CLM at 16.7% + 83.3% and 33.3% + 66.7% combinations were very effective in supporting mycelial growth and quicker colonization of fungus, and mother spawn yield. The spawn that was obtained from these combinations yielded higher sporophore as well. The fungus did not rapidly colonize on other combinations (50% + 50%, 66.7% + 33.3% and 83.3% + 16.7%), and was completely unable to grow on CLM 100%. Combination of rice straw and CLM at 75% + 25% and 50% + 50% as bed substrate contributed higher sporophore yield. Analysis of the substrates indicated variation in their chemical and mineral composition, but they were good sources of N, P and Ca. The prospects of exploring CLM for the mushroom cultivation are discussed.     

Microbial protein from leguminous and non-leguminous substrates

The biodegradation of leguminous and non-leguminous organic materials by Pleurotus sajor-caju and P. ostreatus was studied. Comparisons were made between mushroom yield on both types of substrates. The conversion percentage from dry substrate to fresh mushroom (biological efficiency) was determined. Mushrooms were analyzed for their protein content, carbohydrates, percentages of ash, fat content and crude fibre. The energy value of fruit bodies was computed. The yield obtained from leguminous substrates was significantly high as compared to that yield which was obtained from non-leguminous substrates. The lowest yield of P. sajor caju (10 g ± 0.3 g) and P. ostreatus (6.5 g ± 1.2 g) was obtained using the Bougainuillea substrate and the highest one (519 g ± 16 g, P. sajor-caju and 488 g ± 18 g, P. ostreatus) using nitrogen-fixing leguminous Leucaena leucocepholea. The nitrogen content in fruit bodies was found to be higher with leguminous substrate than with non-leguminous ones.     

Removal of cadmium by Pleurotus sajor-caju basidiomycetes

The bioaccumulation of cadmium by the white rot fungus Pleurotus sajor-caju onto dry biomass was investigated using aqueous media with concentrations in the range of 0.125 mM–1.0 mM The highest cadmium uptake (between 88.9 and 91.8%) was observed with aerobic fungal biomass from the exponential growth phase. Up to 1.0 mM cadmium gradually inhibited mycelium development, but never blocked it completely. Freeze-dried, oven-dried and non-metabolizing live Pleurotus sajor-caju biomass types were tested for their capacity to adsorb the test ion Cd²⁺ within the pH range of 4.5 to 6.0. Freeze–dried biomass proved to be the most efficient biomass type for Cd²⁺ metal adsorption. Therefore, Pleurotus sajor-caju may be used for heavy metal removal and bioremediation.     

Estimation of the growth rate of Pleurotus on stacked straw

A simple visual method to estimate the linear growth rate of fungal mycelia on stacked straw is described. It has been used to evaluate the growth of the fungus Pleurotus sajor-caju on pasteurized and steam-exploded straw. The maximum linear growth rates ranged from 0.92 to 1.0 cm/d with the two treatments; the fungus seemed to be able to overcome inhibition of its growth. No growth was observed on straw treated with ammonia.     

Decolorization of textile dyes by enzymatic extract and submerged cultures of <Emphasis Type="Italic">Pleurotus sajor-caju</Emphasis>

Pleurotus sajor-caju PS2001 was screened in Petri dish plates to assess the dye-decolorizing ability of industrial textile dyes. P. sajor-caju PS2001 was also cultivated in solid-state fermentation containing sawdust of Pinus sp. and wheat bran to obtain the enzymatic extract, showing laccase and manganese-peroxidase activity, which was used to test the capacity to degrade the textile dyes. Additional tests of decolorization were performed in liquid cultures. Anthraquinone-type textile dyes proved to be substrates for the enzymatic system of P. sajor-caju PS2001. Cultures in Petri dish plates showed that the anthraquinone dye Reactive Blue 220 can act as a redox mediator for the enzymatic reactions involved in the decolorization process, and enables the azo dye degradation. Reactive Blue 220 and Acid Blue 280 were completely decolorized in 30 min and 60 min, respectively, during the tests with precipitated enzymatic extract, while the azo dyes showed resistance to degradation. Additionally, in submerged cultures with dyes, veratryl alcohol oxidases and lignin peroxidase activities were observed. These results suggest that the strain P. sajor-caju PS2001 has great potential for use in the bioremediation technology of recalcitrant pollutant such as textile effluents.     

Biodegradation of the cellulose component of rice straw byPleurotus sajor-caju

Pleurotus sajor-caju is an efficient degrader of the cellulose component of rice straw. Protein contents of the biodegraded straw after fungal growth increased from 1.7 to 10.0 %. Crude fibre and cellulose contents decreased from 32.6 and 45.0 to 6.3 and 17.8 %, respectively. The in vivo digestibility of the biodegraded rice straw increased by 34.1 %.     

Trichome-borne and artificially applied acylsugars of wild tomato deter feeding and oviposition of the leafminer Liriomyza trifolii

Oviposition and adult feeding of the leafminer Liriomyza trifollii (Burgess) (Diptera, Agromyzidae) on Lycopersicon pennellii (Corr.) D'Arcy and its F₁ hybrid with Lycopersicon esculentum (Mill.) was significantly less than that on the cultivated tomato, L. esculentum. The resistance of L. pennellii and the F₁ was reduced following rinsing of foliage with ethanol. Resistant attributes of L. pennellii were transferred to L. esculentum through appression of L. pennellii foliage to L. esculentum leaflets. Application of purified 2,3,4-tri-O-acylglucoses (the principal component of type IV glandular trichome exudate of L. pennellii) to L. esculentum significantly decreased feeding and oviposition on L. esculentum leaflets by 61–99%. Therefore the principal mechanism of resistance to this leafminer by L. pennellii is the secretion of these acylglucoses. Dose response analysis of acylglucoses applied to L. esculentum shows that dosages as low as 10% those found on L. pennellii provide large reductions (91%) in leaf punctures and mines.     

Fungal degradation of lantadene A, the pentacyclic triterpenoid hepatotoxin of lantana plant

Seven white-rot fungi, known to degrade complex biomolecules and xenobiotics were used for investigation on biodegradation of lantadene A (LA), the bioactive pentacyclic triterpenoid of Lantana camara. Pleurotus sajor-caju and Merulius tremellosus PRL-2845 did not degrade LA. Trametes versicolor MTCC-138, Heterobasidion annosum MTCC-146, Phellinus pini RAB-83-19, Pleurotus ostreatus MTCC-142 and Phlebia radiata 2 utilized LA to the extent of 11–15.7%. This is the first report on the fungal degradation of a pentacyclic triterpenoid.     

Accumulation and degradation of dead-end metabolites during treatment of soil contaminated with polycyclic aromatic hydrocarbons with five strains of white-rot fungi

The white-rot fungi Trametes versicolor PRL 572, Trametes versicolor MUCL 28407, Pleurotus ostreatus MUCL 29527, Pleurotus sajor-caju MUCL 29757 and Phanerochaete chrysosporium DSM 1556 were investigated for their ability to degrade the polycyclic aromatic hydrocarbons (PAH) anthracene, benz[a]anthracene and dibenz[a,h]anthracene in soil. The fungi were grown on wheat straw and mixed with artificially contaminated soil. The results of this study show that, in a heterogeneous soil environment, the fungi have different abilities to degrade PAH, with Trametes showing little or no accumulation of dead-end metabolites and Phanerochaete and Pleurotus showing almost complete conversion of anthracene to 9,10-anthracenedione. In contrast to earlier studies, Phanerochaete showed the ability to degrade the accumulated 9,10-anthracenedione while Pleurotus did not. This proves that, in a heterogeneous soil system, the PAH degradation pattern for white-rot fungi can be quite different from that in a controlled liquid system. Received: 20 March 1996 / Received revision: 2 July 1996 / Accepted: 8 July 1996     

Comparative study on the growth and yield of<Emphasis Type="Italic"> Pleurotus ostreatus</Emphasis> mushroom on different lignocellulosic by-products

Eight lignocellulosic by-products were evaluated as substrates for cultivation of the oyster mushroom, Pleurotus ostreatus (Jacq. ex. fr) Kummer. The yields of mushroom on the different substrates were 183.1, 151.8, 111.5, 87.8, 49.5, 23.3, 13.0 and 0.0 g for composted sawdust of Triplochiton scleroxylon, rice straw, banana leaves, maize stover, corn husk, rice husk, fresh sawdust, and elephant grass, respectively. The biological efficiency (BE) followed the same pattern and ranged from 61.0% for composted sawdust to 0.0% for elephant grass. The yield of mushroom was positively correlated to cellulose (r ² =0.6), lignin (r ² =0.7) and fibre (r ² =0.7) contents of the substrates. Based on the yield and BE of the substrates tested, rice straw appeared to be the best alternate substrate for growing oyster mushrooms. Electronic Publication     

Diet-induced food preference by Manduca sexta larvae: acceptable non-host plants elicit a stronger induction than host plants

Diet-induced changes in food preference by fifth instar larvae of the tobacco hornworm, Manduca sexta (Johan.) (Lepidoptera, Sphingidae), were examined. Two groups of larvae with different diet experience were used: larvae reared on a host or on an acceptable non-host plant species. Each group of larvae was offered a choice between leaf discs from each rearing plant species (2-plant choice test) and food preference was measured as the consumption of one plant species relative to that of the other plant species. Diet-induced changes in preferences were larger with the host versus acceptable non-host plant pairs Solanum pseudocapsicum (L.) versus Raphanus sativus (L.), Lycopersicon esculentum (Mill.) versus Vigna sinensis (Savi), and Datura innoxia (L.) versus V. sinensis than with the host versus host plant pairs L. esculentum versus Capsicum annuum (L.) and L. esculentum versus D. innoxia. To examine how much the food preference had been altered for each test plant species alone, two other groups of larvae were offered a choice between leaf discs from a single plant species and filter paper discs laced with distilled water (1-plant choice test). Larvae preferred the dietary plant species more strongly than the non-dietary plant species in tests using the following plant species: for C. annuum with C. annuum and L. esculentum as diets, for V. sinensis with V. sinensis and L. esculentum or D. innoxia as diets, and for R. sativus with R. sativus and S. pseudocapsicum as diets. The preference for the hosts L. esculentum and D. innoxia did not change significantly after rearing larvae on different hosts or on an acceptable non-host. Thus, diet-induction by M. sexta larvae results in an enhancement of preference for the dietary plant species which is much stronger with acceptable non-hosts than with hosts.     

Mycelium growth kinetics and optimal temperature conditions for the cultivation of edible mushroom species on lignocellulosic substrates

The influence of environmental parameters on mycelial linear growth ofPleurotus ostreatus, P. eryngii, P. pulmonarius, Agrocybe aegerita, Lentinula edodes, Volvariella volvacea andAuricularia auricula-judae was determined in two different nutrient media in a wide range of temperature, forming the basis for the assessment of their temperature optimaV. volvacea grew faster at 35°C,P. eryngii at 25°C,P. ostreatus andP. pulmonarius at 30°C,A. aegerita at 25 or 30°C andA. auricula-judae at 20 or 25°C depending on the nutrient medium used andL. edodes at 20 or 30°C depending on the strain examined. The mycelium extension rates were evaluated on seven mushroom cultivation substrates: wheat straw, cotton gin-trash, peanut shells, poplar sawdust, oak sawdust, corn cobs and olive press-cake. The mycelium extension rates (linear growth and colonization rates) were determined by the ‘race-tube’ technique, and were found to be the highest on cotton gin-trash, peanut shells and poplar sawdust forPleurotus spp. andA. aegerita. Wheat straw, peanut shells and particularly cotton gin-trash supported fast growth ofV. volvacea, whereas wheat straw was the most suitable substrate forL. edodes andA. auricula-judae. Supplemented oak sawdust and olive press-cake were poor substrates for most species examined, white almost all strains performed adequately on corn cobs.     

Studies on cultivation,biological efficiency and chemical analysis of Pleurotus sajor-caju (FR.) SINGER on different bio-wastes

Three different kinds of biomass, namely Populus deltoides, Eupatorium adenophorum and sericulture waste were used individually for the cultivation of Pleurotus sajor-caju, alone and mixed with paddy straw. P. sajor-caju, when used alone, exhibited a very good colonizing ability on these substrates, except in sericulture waste. The biological efficiency of P. deltoides and E. adenophorum when used as pure substrate was 75 and 77%, respectively, but it increased to 102% when P. sajor-caju was cultivated in a mixture with paddy straw in a ratio of 1:2. Experiments examining the growth on sericulture waste in both pure and mixed substrate are encouraging. From the analysis of substrate before and after the cultivation of P. sajor-caju it was noted that subsstrates were enriched in their protein content as a result of growth of this mushroom. The percentage of degradation of cellulose, hemicellulose and lignin showed that P. sajor-caju is capable of utilizing all three major components. The fruit bodies of P. sajor-caju were analyzed for crude protein content, crude fat and carbohydrate content. The energy values in the fruit bodies of P. sajor-caju and different organic wastes were found to vary from 282 to 309 kcal/100 g and from 319 to 467 kcal/100 g, respectively. It was found, however, that the energy recovery from organic wastes by fruit bodies was very low, i.e. 4.19-8.73 kcal/100g of dry substrate.     

Biological efficiency and nutritive value of Pleurotus sajor-caju cultivated on different agro-wastes

The oyster mushroom, Pleurotus sajor-caju (Fr.) Singer, was cultivated on a number of agro-residues and their mixtures. Biological efficiency, defined as the percentage conversion of substrate into fruit bodies on a dry weight basis, was found to be maximum on paddy straw supplemented with cotton seeds (12·82 g/100 g substrate). Biochemical changes effected in the substrates as a result of mushroom growth, in terms of nitrogen content and degradation of cellulose, hemicellulose and lignin components, were monitored. The proximate compositions of fruit bodies of the mushroom in terms of protein, total carbohydrates, fat, fibre and ash were determined. The crude protein and total carbohydrate contents varied from 26·3% to 36·7% and 41·2% to 47·1%, respectively, on various residues. The variation in the contents of crude fat, crude fibre and ash ranged from 1·7% to 2·0%, 11·7% to 17·0% and 6·1%, respectively, on different residues. The energy value of the fruit bodies was found to be between 275 and 300 kCal/100 g, whereas the energy recovery of the substrate in the fruit bodies was from 5% to 10%.