Influence of Oxygen Supply on Growth and Laccases Production by Pleurotus sajor-caju PS-2001 in Submerged Process

Abstract (1) Background: Oxygen supply is an important parameter to be considered in submerged cultures. This study evaluated the influence of different conditions for dissolved oxygen (DO) concentration on laccases activities and growth of Pleurotus sajor-caju PS-2001 in submerged process in stirred-tank bioreactor. (2) Methods: Initially, three different conditions were tested: uncontrolled DO and minimum levels of 30% and 80% of saturation, with the pH controlled between 4.5 and 7.0. (3) Results: Best results were observed at 30% DO (26 U mL-1 of laccases at 96 h), whereas higher mycelial biomass was observed at 30% and 80% DO (above 4.5 g L-1). Four different conditions of DO (uncontrolled, 10%, 30% and 50% of saturation) were tested at pH 6.5, with higher laccases activity (80 U mL-1 at 66 h) and lower mycelial growth (1.36 g L-1 at 90 h) being achieved with DO of 30%. In this test, the highest values for volumetric productivity and specific yield factor were determined. Under the different pH conditions tested, the production of laccases is favoured at DO concentration of 30% of saturation, while superior DO levels favours fungal growth. (4) Conclusion: The results indicate that dissolved oxygen concentration is a critical factor for the culture of P. sajor-caju PS-2001 and has important effects not only on laccases production but also on fungal growth.

Pleurotus spp. cultivation on Brachiaria sp. straw treatment with alkaline water

Abstract The aim of this research was to evaluate the efficiency of aqueous alkali-treated Brachiaria straw for the cultivation of appropriate species of oyster mushroom. The substrate used in the cultivation of various Pleurotus spp. was soaked for 20 min by using two different procedures: (i) 0.5-2.0% Ca(OH)2 in 100 L water, and (ii) 50-250 L water. As a result, 1% Ca(OH)2 dissolved in 100 L water and 3.5 kg of Brachiaria straw presented the best production. The most suitable species for the application of the present method were P. pulmonarius and P. sapidus. The success of this technique is directly related to the concentration of Ca(OH)2 and water, the species, and the origin and quality of raw material used as the substrate in the production of oyster mushroom.

Iron bioaccumulation in mycelium of Pleurotus ostreatus

Pleurotus ostreatus is able to bioaccumulate several metals in its cell structures; however, there are no reports on its capacity to bioaccumulate iron. The objective of this study was to evaluate cultivation variables to increase iron bioaccumulation in P. ostreatus mycelium. A full factorial design and a central composite design were utilized to evaluate the effect of the following variables: nitrogen and carbon sources, pH and iron concentration in the solid culture medium to produce iron bioaccumulated in mycelial biomass. The maximum production of P. ostreatus mycelial biomass was obtained with yeast extract at 2.96 g of nitrogen L−1 and glucose at 28.45 g L−1. The most important variable to bioaccumulation was the iron concentration in the cultivation medium. Iron concentration at 175 mg L−1 or higher in the culture medium strongly inhibits the mycelial growth. The highest iron concentration in the mycelium was 3500 mg kg−1 produced with iron addition of 300 mg L−1. The highest iron bioaccumulation in the mycelium was obtained in culture medium with 150 mg L−1 of iron. Iron bioaccumulation in P. ostreatus mycelium is a potential alternative to produce non-animal food sources of iron.

Morphology and mycelial growth rate of Pleurotus spp. strains from the Mexican mixtec region

Two native Pleurotus spp. strains (white LB-050 and pale pink LB-051) were isolated from rotten tree trunks of cazahuate (Ipomoea murucoides) from the Mexican Mixtec Region. Both strains were chemically dedikaryotized to obtain their symmetrical monokaryotic components (neohaplonts). This was achieved employing homogenization time periods from 60 to 65 s, and 3 day incubation at 28 °C in a peptone-glucose solution (PGS). Pairing of compatible neohaplonts resulted in 56 hybrid strains which were classified into the four following hybrid types: (R1-n xB1-n, R1-n xB2-1, R2-n xB1-n and R2-n xB2-1). The mycelial growth of Pleurotus spp. monokaryotic and dikaryotic strains showed differences in texture (cottony or floccose), growth (scarce, regular or abundant), density (high, regular or low), and pigmentation (off-white, white or pale pink). To determine the rate and the amount of mycelium growth in malt extract agar at 28 °C, the diameter of the colony was measured every 24 h until the Petri dish was completely colonized. A linear model had the best fit to the mycelial growth kinetics. A direct relationship between mycelial morphology and growth rate was observed. Cottony mycelium presented significantly higher growth rates (p < 0.01) in comparison with floccose mycelium. Thus, mycelial morphology can be used as criterion to select which pairs must be used for optimizing compatible-mating studies. Hybrids resulting from cottony neohaplonts maintained the characteristically high growth rates of their parental strains with the hybrid R1-n xB1-n being faster than the latter.

Lignocellulolytic enzyme production of Pleurotus ostreatus growth in agroindustrial wastes

The mushroom Pleurotus ostreatus has nutritional and medicinal characteristics that depend on the growth substrate. In nature, this fungus grows on dead wood, but it can be artificially cultivated on agricultural wastes (coffee husks, eucalyptus sawdust, corncobs and sugar cane bagasse). The degradation of agricultural wastes involves some enzyme complexes made up of oxidative (laccase, manganese peroxidase and lignin peroxidase) and hydrolytic enzymes (cellulases, xylanases and tanases). Understanding how these enzymes work will help to improve the productivity of mushroom cultures and decrease the potential pollution that can be caused by inadequate discharge of the agroindustrial residues. The objective of this work was to assess the activity of the lignocellulolytic enzymes produced by two P. ostreatus strains (PLO 2 and PLO 6). These strains were used to inoculate samples of coffee husks, eucalyptus sawdust or eucalyptus bark add with or without 20 % rice bran. Every five days after substrate inoculation, the enzyme activity and soluble protein concentration were evaluated. The maximum activity of oxidative enzymes was observed at day 10 after inoculation, and the activity of the hydrolytic enzymes increased during the entire period of the experiment. The results show that substrate composition and colonization time influenced the activity of the lignocellulolytic enzymes.

Cinética micelial dos fungos comestíveis Pleurotus ostreatus e Lentinula edodes em resíduos lignocelulósicos / Mycelial kinetics of edible fungi Pleurotus ostreatus and Lentinula edodes in lignocellulosic residues

O objetivo do trabalho foi avaliar o crescimento micelial, em placa de Petri, de dois fungos comestíveis (Pleurotus ostreatus e Lentinula edodes) em seis meios de cultura [(malte-ágar, serragemdextrose-ágar-marupá (SDA-MA), serragem-dextrose-ágar-cajuí (SDA-CA), serragem-dextroseágar-açaí (SDA-AÇA), serragem-dextrose-ágar-banana 50% (BAN 50%) e serragem-dextroseágar-banana 100% (BAN 100%)]. O delineamento experimental foi inteiramente casualizado, em esquema fatorial 6 x 2. Cada tratamento constou de seis repetições, correspondente a uma placa de Petri, totalizando 72 unidades experimentais. Verificou-se que, em todos os meios à base de resíduos, o P. ostreatus apresentou um melhor desenvolvimento micelial (81,00; 64,66; 81,00; 50,16; e 33,33 mm, para SDA-MA, SDA-CA, SDA-AÇA, BAN 50% e BAN 100%, respectivamente) que o L. edodes (32,00; 31,66; 27,66; 37,33; e 21,83 mm, para SDA-MA, SDA-CA, SDA-AÇA, BAN 50% e BAN 100%, respectivamente). Também constatou-se que, para os L. edodes, não houve vantagem, em relação ao crescimento micelial, no uso de meios à base de resíduos comparado ao meio malteágar (testemunha), o qual obteve o melhor desempenho (62,17mm). Já para o P. ostreatus, os meios SDA-MA e SDA-AÇA apresentaram as maiores médias de crescimento (81 mm), o que representa um incremento de crescimento de 34% em relação ao meio testemunha (malte-ágar), cujo média de crescimento foi de 60,33mm. Assim, de uma forma geral, os resíduos testados indicam potencial de aproveitamento na fungicultura, especialmente para o cultivo de P. ostreatus.

The objective of this work was to evaluate the mycelial growth of 2 edible fungi (Pleurotus ostreatus and Lentinula edodes) in 6 culture media [(malt-agar, sawdustdextrose-agar-marupá (SDA-MA), sawdust-dextrose-agar-cajuí (SDA-CA), sawdust-dextrose-agaraçaí (SDA-AÇA), sawdust-dextrose-agar-banana 50% (BAN 50%) and sawdust-dextrose-agar-banana 100% (BAN 100%)], in Petri dishes. The experimental design was totally randomized, in a 6x2 factorial scheme. Each treatment consisted of six repetitions in 1 Petri dish, totaling 72 experimental units. It was verified that P. ostreatus presented better mycelial development (81.00; 64.66; 81.00; 50.16 and 33.33mm for SDA-MA, SDA-CA, SDA-AÇA, BAN 50% and BAN 100%, respectively) than L. edodes (32.00; 31.66; 27.66; 37.33 and 21.83mm for SDA-MA, SDA-CA, SDA-AÇA, BAN 50% and BAN 100%, respectively). It was also verified that there was no advantage for L. edodes in relation to mycelial growth, when media based on residues were used, compared to malt-agar medium (control), which obtained the best performance (62.17mm). As for P. ostreatus, SDA-MA and SDA-AÇA medium presented the highest growth averages (81 mm), representing a growth increase of 34% in relation to the control medium (malt-agar), whose growth average was 60.33mm. Thus, the residues tested present potential to be used in fungiculture, especially for the cultivation of P. ostreatus.

Influencia del sustrato utilizado para el crecimiento de hongos comestibles sobre sus características nutraceúticas / The influence of the substrate used for growing edible fungi on their nutraceutic characteristics

Siendo Colombia un país en el cual hay un gran desarrollo de la actividad agraria, generadora de cantidades apreciables de desechos que dan lugar a un problema ambiental, el cultivo de los hongos presenta un potencial en aplicaciones biotecnológicas que derivan de la diversidad metabólica de los mismos. Dicho potencial está tanto en la producción de los hongos como alimentos con óptimas calidades nutricionales, como en la obtención a partir de las setas de productos bioactivos que permitirían en un futuro no muy lejano contribuir a la economía del país y a la descontaminación ambiental. Dentro del reino fungi, las especies de Pleurotus pueden crecer sobre una amplia variedad de sustratos y tienen especiales propiedades para degradar los componentes lignocelulósicos presentes en mayor proporción en los residuos de la agroindustria. El objetivo del presente estudio fue el de evaluar el efecto del sustrato sobre las propiedades nutricionales o nutriceúticas de hongos del género Pleurotus. Como resultado se determinó que efectivamente la composición de los hongos en cuanto al contenido de proteínas netas, fibra, humedad, cenizas, carbohidratos y grasas totales varía con el sustrato empleado, lo que incide directamente en las propiedades antes anotadas, si se tiene en cuenta que dentro de los componentes determinados se encuentran metabolitos como polisacáridos y esteroles con bioacciones previamente reportadas. De igual manera, se encontró que estas variaciones son diferentes dependiendo de la especie.

Being Colombia a country in which there is a great development of the generating agrarian activity of appreciable quantities of waste that they give place to an environmental problem, the cultivation of the mushrooms presents a potential in biotechnical applications that derive of the metabolic diversity of the same ones. This potential is in the production of the mushrooms like in foods with good nutritional qualities. For instance in the obtaining starting from the mushrooms of bioactive products that would not allow in a very distant future to contribute to the economy of the country and the environmental decontamination. Inside the fungi Kingdom, the Pleurotus species can grow about a wide substrate variety and they have special properties to degrade the lignocelulosic component present in bigger proportions in the residuals of the agroindustry. The objective of the present study was of evaluating the substrate effect on the nutritional and/or nutriceutical quality of mushrooms of the Pleurotus gender. As a result it was determined that indeed the composition of the mushrooms as for the content of net proteins, fiber, humidity, ashes, carbohydrates and total fats, varies with the substrate used, what impacts directly in their properties, taking into account that in certain components are metabolites such as polysaccharides and sterols with bioactions previously reported. Similarly it was found that these variations are different depending on the species.

Evaluación del crecimiento y producción de Pleurotus ostreatus sobre diferentes residuos agroindustriales del departamento de Cundinamarca / Evaluation of growth and production of pleurotus ostreatus on different agroindustrials wastes of Cundinamarca

Se llevó a cabo la evaluación del cultivo de Pleurotus ostreatus, para determinar el residuo sobre el cual este hongo genera mejor crecimiento y producción. Los sustratos evaluados fueron residuos agroindustriales del departamento de Cundinamarca (capacho de uchuva, cáscara de arveja y tusa de maíz); teniendo como sustrato control el aserrín de roble. Las mezclas a evaluar fueron empacadas en bolsas de 1Kg de volumen de mezcla de sustrato, del cual el 78 por ciento fue el residuo agroindustrial. Se esterilizaron e inocularon con 30g de semillas de Pleurotus ostreatus, adquiridas comercialmente. Se evaluó el tiempo de corrida del micelio, el diámetro de los carpóforos, el número de hongos producidos por bolsa, el peso fresco, la eficiencia biológica y el rendimiento de cada uno de los sustratos trabajados. Finalmente, el mejor sustrato para el crecimiento y producción de Pleurotus ostreatus fue el capacho de uchuva ya que alcanzó una eficiencia biológica de 76.1 por ciento en un período total de producción de 41 días y una rentabilidad de 39.03 Kg/m2 con excelentes características organolépticas, considerándose así un sustrato adecuado y eficiente para el cultivo de este hongo.

The culture of Pleurotus ostreatus was evaluated to determine the best waste on which this mushroom can show the highest growth and production rates.. The substrates evaluated were agroindustrial wastes of theDepartment of Cundinamarca (dry skin of goldenberries (Physalis), skin of pea pods and maize cobs). The control substrate was sawdust of oak. The mixtures evaluated were packed in bags of 1 kg containing 78 % ofagroindustrial waste of the volume of substrate mixture . Mixtures were sterilized and inoculated with 30 g ofseeds of Pleurotus ostreatus obtained commercially. Running time of the mycelium, diameter of fruit bodies,number of fruit bodies produced per bag, fresh weight, biological efficiency, and yield were evaluated on eachof the substrates. Finally, the best substrate for the growth and production of Pleurotus ostreatus was the dryskin of goldenberries (Physalis) with a biological efficiency of 76.1% after a total production period of 41 days and a yield of 39.03 Kg/m2 with excellent organoleptic characteristics, therefore being an adequate and efficient substrate for cultivating this mushroom.