The microbial conversion of different agricultural residues and its biological efficiency

A number of agricultural residues such as Saccharum munja Roxb. (Sarkanda), Oryza sativa L. (Paddy straw, as the control), Vinna unguiculata (L.) Walp (Cowpeas), Abelmoschus esculentum (L.) Moench (Lady's finger), Zea mays L. (Maize) and Cyamopsis tetragonoloba (L.) Taub. (Guar) were used for the cultivation of Pleurotus sajor-caju (Fr.) Singer. The biological efficiency of the fruit bodies of Pleurotus sajor-caju from the above mentioned substrates were found to be 13.47, 11.20, 8.37, 8.31, 6.87, and 6.08 percent, respectively. S. munja and paddy straw were found to be the best substrates for the growth of P. sajor-caju followed by Z. mays, V. unguiculata, A. esculentum, and C. tetragonoloba.     

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.     

Improvement of the bioconversion and biotransformation efficiencies of the oyster mushroom (Pleurotus sajor-caju) by supplementation of its rice straw substrate with oil seed cakes

Supplementing the rice straw substrate colonized by the mushroom, Pleurotus sajor-caju, with powdered oil seed cakes (mustard, niger, sunflower, cotton, and soyabean) increased the mushroom yields between 50 and 100%, compared to the unsupplemented substrate. Oil seed cake supplementation also effected an increase in the solubility of the rice straw substrate; there was an increase in the contents of free sugars and amino acids, and a decrease in cellulo-hemicellulosics. Correspondingly, there was also an increase in the activities of carboxymethylcellulase, hemicellulase, and protease. In vitro dry matter enzymatic digestibility measured by two-step enzymatic digestibility of the spent straw (material remaining from the straw substrate, supplemented with the oil seed cakes), indicated a significant increase over that of the spent straw derived from the unsupplemented lot.     

Utilization of spent agro-residues from mushroom cultivation for biogas production

Summary Various spent agro-residues obtained after cultivation of the edible mushroom Pleurotus sajor-caju were used in anaerobic digestors for production of biogas. The changes that take place in the residues during bioconversion were quantified in terms of composition of cellulose, hemicellulose, lignin, carbon and nitrogen. These mycostraws resulted in increased biogas production over the untreated ones, which varied from 21.5% in the case of spent bagasse to 38.8% in the case of spent paddy straw. The increased biogas generation by the spent residues seems to be due to the increased susceptibility to digestion and more favourable C/N ratio of the residues. Offprint requests to: V. S. Bisaria     

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 of spent shiitake substrate for production of the oyster mushroom,Pleurotus sajor-caju

Pleurotus sajor-caju was produced on a basal medium containing spent shiitake substrate plus 10% wheat bran and 10% millet. An analysis of the fibrous composition of the spent shiitake substrate revealed that 85% of the original hemicellulose, 44% of the original cellulose and 77% of the original lignin was not consumed during production of a full crop (78% biological efficiency) of shiitake (63-day harvest period). To produce P. sajor-caju, the spent shiitake substrate was ground, air dried, supplemented, pasteurized with live steam and spawned. Highest yields (79% biological efficiency) of P. sajor-caju were obtained by supplementing the spent shiitake basal medium with 12% soybean and 1% CaCO₃. Increases in percentage biological efficiency and mushroom size were positively correlated with increasing levels of CaCO₃ added to the basal medium.     

Cultivation of Oudemansiella tanzanica nom. prov. on agricultural solid wastes in Tanzania

The edible mushroom Oudemansiella tanzanica nom. prov., which is new to science, has been studied as a potential crop to reduce agricultural solid wastes and increase domestic mushroom production. The substrates sawdust, sisal waste and paddy straw supplemented with chicken manure resulted in the highest biological efficiencies of any mushroom cultivated in Tanzania so far. In addition, the mushroom has one of the shortest cultivation cycles at 24 d. Despite the fact that the mushroom extracts substantial amounts of nutrients, the spent substrate can be used as fodder, as a soil conditioner and fertilizer and in bioremediation.     

Influence of formaldehyde-treated soybean and commercial nutrient supplementation on mushroom (Pleurotus sajor-caju) yield and in-vitro dry matter digestibility of spent substrate

Summary Pleurotus sajor-caju 537 was grown on chopped, pasteurized wheat straw non-supplemented and supplemented with formaldehyde-treated soybean, commercial delayed-release nutrient (SpawnMate II SE) or vegetable oil. Yield was 2.1-fold higher for substrate supplemented (12% dry wt) with low-volume formaldehyde-treated soybean as compared to non-supplemented substrate. Mushroom yield from substrate supplemented with commercial nutrient was 1.7-fold higher than yield from non-supplemented substrate. As the supplement level increased, the mushroom yield response increased. The yield ranged from 3.56 kg/m² for non-supplemented substrate to 7.36 kg/m² for substrate supplemented (12% dry wt) with formaldehyde-treated soybean. The type of supplement affected in vitro dry matter digestibility (IVDMD) of spent substrate; commercial supplement resulted in higher IVDMD compared to formaldehyde-treated substrate. An opportunity exists for commercial development of a nutrient(s) specifically designed for Pleurotus cultivation.     

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.     

Occurrence and characterization of injuries caused by Mycotretus apicalis Lacordaire, 1842 (Coleoptera: Erotylidae) on cultivation of Pleurotus sajor-caju

When carrying out experiments on the production of the edible mushroom Pleurotus sajor-caju in the Laboratory of Edible Mushrooms, Universidade Federal de Lavras, Lavras, Brazil, in the second half of 2007, the presence of beetles later identified as belonging to the species Mycotretus apicalis was verified. This is the first recorded instance of this insect in cultures of P. sajor-caju in Brazil. The larvae and adults of this insect feed on the fruiting bodies of commercial harvests, resulting in reduction in mushroom quality. To provide evaluation of the injuries caused by these insects, substrates colonized by P. sajor-caju were infested with 4, 8, 16, 32 and 64 insects per block of substrate being the qualitative and quantitative losses then noted. Despite the lack of an observed decrease in biological efficiency, the injuries caused by these insects affected the commercial quality of the mushrooms, which may result in economic losses. The results showed that infestations of 32 insects per 0.8 kg of substrate led to a depreciation in the prices of mushrooms meant to be sold.     

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%.     

Cultivation of the Dible Mushroom Lentinula edodes (Shiitake) in Pasteurized Wheat Straw – Alternative Use of Georthermal Energy in Mexico

Five edible Lentinula edodes strains were evaluated. The mushrooms were cultivated on a wheat straw substrate that was previously pasteurized by immersion in water heated by residual geothermal vapor, which was also used to warm incubation and production rooms. Finely chopped wheat straw (Triticum aestivum L.) was pasteurized and then spawned with supplemented spawn capable of supplying nutrients and enriching the substrate, with the expectation of yield improvement. The samples were incubated for 60 days before the production started and thus, the mushrooms produced had pileus diameters ranging from 5 to 20 cm. The yields fluctuated from 6.2 to 13.9 % (fresh weight of mushrooms/fresh weight of substrate). Biological efficiency ranged from 24.8 to 55.6 % (fresh weight of mushrooms/dry weight of substrate), while the production rate reached varied from 0.19 to 0.55 % (biological efficiency/production time starting from inoculation). The cultivation system evaluated here offers the possibility of lowering production costs by cultivating the mushroom on easily obtainable substrate and shortening the culture cycle. The efficiency of this use of geothermal energy and supplemented spawn for shiitake mushroom cultivation on non‐sterilized substrates was proven.     

Performance of olive mill solid waste as a constituent of the substrate in commercial cultivation of Agaricus bisporus

The feasibility of using olive mill waste (OMW) as an ingredient in the substrate used for cultivation of Agaricus bisporus (Lange) Sing. was studied in a large-scale cultivation trial, concerning 2500 m² of mushroom growing area, at a specialized mushroom farm. Standard commercial cultivation technique involving compost preparation, spawning, casing and harvesting was used. The performance indicators such as mushroom yield, biological efficiency, market quality as well as horticultural value of the spent compost showed that the compost prepared with OMW was superior to the control compost in all the categories. The OMW-amended substrate supported higher populations of beneficial microorganisms especially, actinomycetes which enabled the breakdown of the compost ingredients. It is suggested that OMW is a suitable ingredient for the preparation of mushroom substrate. We have demonstrated that conversion of OMW (a liability) into value-added mushroom substrate (an asset) is an effective waste management tool in oleaculture.     

Cultivation of different strains of king oyster mushroom (Pleurotus eryngii) on saw dust and rice straw in Bangladesh

Pleurotus eryngii is a popular mushroom due to its excellent consistency of cap and stem, culinary qualities and longer shelf life. In Bangladesh, where Pleurotus mushrooms are very popular, P. eryngii may take position among the consumers, but currently this mushroom is not cultivated in large scale there. In this study, 3 strains of P. eryngii such as Pe-1 (native to Bangladesh), Pe-2 (germplasm collected from China) and Pe-3 (germplasm collected from Japan) were cultivated on saw dust and rice straw and their growth and yield parameters were investigated. Pe-1 on saw dust showed the highest biological yield and efficiency (73.5%) than other strains. Also, the mycelium run rate and number of fruiting bodies were higher in Pe-1 than other two strains. The quality of mushroom strains was near about similar. On saw dust, the yield and efficiency were better than those cultivated on rice straw, however, on straw; the mushroom fruiting bodies were larger in size. This study shows the prospects of P. eryngii cultivation in Bangladesh and suggests further study in controlled environment for higher yield and production.     

A new circular economy approach for integrated production of tomatoes and mushrooms

Spent mushroom Substrate is the by-product generated at the end of the mushroom growing cycle. It can be used in agriculture for different purposes, including seedling production, soil conditioning or application as an organic fertilizer. Tomato is one of the world?s most important crops, requiring considerable care, in terms of both nutrition and disease control. The objective of this study was to investigate the viability of spent mushroom substrate as a nutrient source for tomato seedlings and develop an integrated tomato and mushroom co-production system. For seedling production, different compositions were evaluated with spent mushroom substrate from Pleurotus ostreatus or substrate colonized with Agaricus bisporus. The parameters evaluated comprised germination rate, seedling quality and physicochemical analysis. A tomato and mushroom integrated production system was developed using a 40-liter pot divided into upper (spent mushroom substrate and soil), middle (spent mushroom substrate from P. ostreatus) and lower (gravel) layers. For seedlings production, plants treated with the substrate colonized with A. bisporus presented a superior root length (10.1 cm) and aerial part length (6.6 cm). Co-production of tomato and mushrooms was also shown to be viable. In this co-cultivation system between tomato and mushroom, the treatment with the substrate colonized with A. bisporus differed from others, with this treatment presenting high yields of tomato (2.35 kg/plant pot) and mushrooms (1.33 kg/plant pot) within the same bucket. With this co-production system, the tomato production time was reduced by 60 days and prolonged continuous mushroom production by 120 days. These findings show a sustainable approach to manage different agroindustrial residues, encouraging the use of these residues for olericulture and fungiculture production.     

Profile of the extracellular lignocellulolytic enzymes activities as a tool to select the promising strains of Volvariella volvacea (Bull. ex Fr.) sing

Out of 26 strains of Volvariella volvacea used, 18 were of ‘typical’ type and possessed all the characteristics of a normal V. volvacea mycelium, while the rest 4 ‘atypical’ type strains showed completely distinct mycelial growth characteristics. The remaining 4 strains grew very slowly and exhibited growth characteristics of single spore isolates of V. volvacea. Strains varied in their extracellular lignocellulolytic activities and strains; OE-274, OE-272 and OE-210 with high ligninase enzymes (laccase and polyphenol oxidase) activities, gave highest mushroom yield on pasteurized paddy straw substrate. On the composted paddy straw substrate, additional two strains, OE-213 and OE-215 with lower activities of ligninases also gave higher mushroom yield. Mushrooms were harvested 3 to 4 d early from the composted substrate than on the pasteurized substrate. Activities of endoglucanase, laccase and polyphenol oxidase were found to be more crucial for mushroom yield on pasteurized substrate, while xylanase and β-glucosidase were more important for composted substrate. Strains also varied in their fruiting bodies quality and the substrate used for mushroom cultivation also affected the fruiting body quality. The superior yielding strains varied in shape, size, weight, colour and contents of sodium and potassium in their fruiting bodies; while contents of carbon, calcium and protein did not vary much with the strains.     

Validation of thermal composting process using olive mill solid waste for industrial scale cultivation of Agaricus bisporus

The production of a substrate containing destoned olive mill solid waste for the cultivation of Agaricus bisporus (Lange) Imbach on an industrial scale was studied. A standard mushroom compost (C) mainly made from straw and poultry manure was compared with the experimental compost (EC) containing the same ingredients as (C) but with added olive mill solid waste (10.6% w/w). Microbial indicators such as counts of heterotrophic microbes and actinomycetes were higher in EC than in C. In addition, compost selectivity as indicated by higher mushroom yield and biological efficiency of EC was higher than that of C. Market quality of the mushrooms produced in both C and EC were comparable. These findings support our work that olive mill solid waste can be used safely in thermal composting process to produce a selective substrate for industrial-scale cultivation of A. bisporus. This study also demonstrates an environmentally sustainable system to manage solid waste from olive oil extraction processes thus overcoming environmental pollution brought about by irrational disposal of the waste on farm lands.     

Optimization of substrate preparation for oyster mushroom (<Emphasis Type="Italic">Pleurotus ostreatus</Emphasis>) cultivation by studying different raw materials and substrate preparation conditions (composting: phases I and II)

In recent years, oyster mushroom (Pleurotus ostreatus) has become one of the most cultivated mushrooms in the world, mainly in Brazil. Among many factors involved in a mushroom production, substrate preparation is the most critical step, which can be influenced by composting management techniques. Looking forward to optimizing the substrate preparation process, were tested different composting conditions (7 and 14 days of composting with or without conditioning), potential raw materials (decumbens grass, brizantha grass and sugarcane straw) and nitrogen supplementation (with or without wheat bran) on oyster mushroom yield and biological efficiency (BE). The substrate composted for 7 days with conditioning showed higher yield and biological efficiency of mushroom (24.04 and 100.54 %, respectively). Substrates without conditioning (7 and 14 days of composting) showed smaller mushroom yield and biological efficiency. Among the raw materials tested, brizantha grass showed higher mushroom yield followed by decumbens grass, sugarcane straw and wheat straw (28.5, 24.32, 23.5 and 19.27 %, respectively). Brizantha grass also showed higher biological efficiency followed by sugarcane straw, decumbens grass and wheat straw (123.95, 103.70, 96.90 and 86.44 %, respectively). Supplementation with wheat bran improved yield and biological efficiency in all substrate formulations tested; thus, oyster mushroom yield and biological efficiency were influenced by substrate formulation (raw materials), supplementation and composting conditions.     

Yield and size of oyster mushroom grown on rice/wheat straw basal substrate supplemented with cotton seed hull

Oyster mushroom (Pleurotus ostreatus) was cultivated on rice straw basal substrate, wheat straw basal substrate, cotton seed hull basal substrate, and wheat straw or rice straw supplemented with different proportions (15%, 30%, and 45% in rice straw substrate, 20%, 30%, and 40% in wheat straw substrate) of cotton seed hull to find a cost effective substrate. The effect of autoclaved sterilized and non-sterilized substrate on growth and yield of oyster mushroom was also examined. Results indicated that for both sterilized substrate and non-sterilized substrate, oyster mushroom on rice straw and wheat basal substrate have faster mycelial growth rate, comparatively poor surface mycelial density, shorter total colonization period and days from bag opening to primordia formation, lower yield and biological efficiency, lower mushroom weight, longer stipe length and smaller cap diameter than that on cotton seed hull basal substrate. The addition of cotton seed hull to rice straw and wheat straw substrate slowed spawn running, primordial development and fruit body formation. However, increasing the amount of cotton seed hull can increase the uniformity and white of mycelium, yield and biological efficiency, and increase mushroom weight, enlarge cap diameter and shorten stipe length. Compared to the sterilized substrate, the non-sterilized substrate had comparatively higher mycelial growth rate, shorter total colonization period and days from bag opening to primordia formation. However, the non-sterilized substrate did not gave significantly higher mushroom yield and biological efficiency than the sterilized substrate, but some undesirable characteristics, i.e. smaller mushroom cap diameter and relatively long stipe length.