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Variation of dissolved oxygen concentration with time, as a function of microbial consumption during interruption and posterior reestablishment of aeration. An assay was performed with the fungal species Rhizopogon nigrescens CBMAI 1472, set at growing temperatures of 25 ± 1 °C and airflow rate of 0.2 vvm
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The study had the objective of examining the aspects involved in the cultivation of ectomycorrhizal fungi for the production of commercially sustainable inoculant to attend the demands of the seedling nursery industry. It focused on certain parameters, such as the oxygen consumption levels, during the cultivation of the ectomycorrhizal fungus Rhizo...
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Barb (Barbonymus balleroides) considerably has economic potential as aquaculture commodity. However, there was still lack of development on aquaculture for this species. This study was conducted to observe the effect of different stocking density on growth of barb. The fish (body weight: 14.89 ± 0.13 g) were stocked in nine floating nets (dimension...
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... Baffled Erlenmeyer flasks show superior mass transfer capacity and shear formation compared with flasks without baffles [28]. An increase in agitation rate generates shear stress, which is usually detrimental to cell integrity [29] and reduces the size of the mycelial aggregates. In submerged cultures of Ganoderma lucidum, the initial volumetric oxygen transfer coefficient affected the growth rate of cells and production of ganoderic acid [30]. ...
Sparassis crispa contains various bioactive substances, such as β-glucan, which exhibits antitumor activity. In this study, we investigated the effect of the mycelial shape of S. crispa and the combination of flask type and agitation method on β-glucan production. With the combination of the Erlenmeyer flask and shaken culture, the mycelia grew in the shape of pellets, whereas with the combination of the baffled Erlenmeyer flask and stirred culture, the mycelia grew in the shape of filaments. The dried cell weight (DCW) and β-glucan production of the filamentous mycelia were 5.91 g/L and 1.71 g/L, respectively, 1.34-fold and 1.73-fold higher, respectively, than that of the pelleted mycelia (4.42 g/L and 0.99 g/L, respectively). The production was further increased using the homogenization process; the DCW was 1.03-fold (7.23 g/L) higher and β-glucan production 1.34-fold (3.50 g/L) higher, respectively, than that without the treatment (7.01 g/L and 2.61 g/L, respectively). In the filamentous mycelia, β-glucan production increased with suppressed ethanol production, and a negative correlation was observed between β-glucan production and ethanol production. In the cultivation of S. crispa mycelia, filamentous mycelia have been suggested to be more suitable for β-glucan production than pelleted mycelia.
Graphical abstract
... It is also more difficult to transfer mass to the hyphae inside the pellets, such as oxygen and other nutrients. In this situation critical conditions can be established, with loss of cell viability (Fig. 2a), production of secondary metabolites and possibly also molecular variations in the composition of the polysaccharides, which may alter the desired bioactivity (Rossi et al. 2002(Rossi et al. , 2017bZhong and Tang 2004). Even the transfer of oxygen from the air bubbles to the culture medium is reduced with the increase in size of the pellets since they occupy space in the fluid differently than the dispersed mycelium, reducing the space for the movement of air bubbles. ...
... In this type of disperser, small fragments of mycelium are no longer reached by the cutting blades when a critical size is established. For other types of homogenizers, care with the fragmentation time may be necessary to avoid pulverizing the inoculums (Rossi et al. 2016(Rossi et al. , 2017b. ...
... In this scenario, quorum sensing phenomena are not being considered, since in bioreactors a small size of the inoculum still contains a very large concentration of cells, far beyond what would be found in a natural environment. However, Rossi et al. (2017b) demonstrated that the size of the inoculum interferes with the specific growth rate of mycelial cells in a bioreactor. This is the result of limitations in the transfer of oxygen that can occur specifically in large and dense pellet morphologies. ...
... For this reason, OTR is commonly use as a scale-up criterion and the accurate value determination is necessary for the successful development of the process [5]. Usually, the increase in OTR by agitation or aeration result in the enhancement of the maximum biomass, but also the kinetic and stoichiometric parameters are equally improved [7][8][9][10][11]. However, a detrimental effect in growth parameters might be achieve when a critical value of OTR is overflow [12]. ...
Oxygen is a key factor during free-state growth of Rhizobium phaseoli or symbiosis with common bean roots. Five different initial oxygen transfer rates (OTRI) were fix by dissolved oxygen control and constants stirrer speed rates to determine the growth of R. phaseoli in a lab-scale bioreactor. The biomass did not presented differences in the maximum concentrations for OTRI of 1.0, 1.7 and 5.9 mmol L⁻¹ h⁻¹. However, a sublethal effect was observed for 11.9 and 20.2 mmol L⁻¹ h⁻¹, where lower biomass, kinetic and stoichiometric parameters were determined. Catalase activity as an oxidative stress indicator was approximately two-fold greater with 20.2 mmol L⁻¹ h⁻¹ than lower OTRI. Polyhydroxybutyrate (PHB) production did not present differences in the maximum concentration. Nevertheless, an increase in PHB accumulation, yield on biomass and specific productivity were determined at the higher OTRI, suggesting a defense mechanism against oxidative stress induce by the enhancement of the oxygen transfer rates.
... In order to guarantee a sufficient supply of ectomycorrhizal inoculum, technologies must be developed for the mass production of ectomycorrhizal fungi mycelia. Submerged mycelial culture of the Lactarius (Ch avez et al., 2015), Pisolithus (Pradella et al., 1991;Rossi et al., 2002), Rhizopogon (Oliveira et al., 2006;Rossi et al., 2016Rossi et al., , 2017, and Tricholoma (Kawagoe et al., 1999;Kim et al., 2010) species has been experimentally performed in stirred and/ or pneumatic tank bioreactors. ...
... Pneumatic bioreactors are the best strategy for the mass production of EM (Rossi et al., 2007), due to the low generation of shear stress and because they enable thorough mixing by the hydrodynamics of air injection (De Jesus et al., 2017;Garcia-Ochoa and Gomez, 2009;Rossi et al., 2017). Pneumatic bioreactors reach the oxygen demand of EM cultures by mass transference via small, homogeneous air bubbles. ...
... In contrast, the substrate never depleted when cultures were carried out at 15 g/L of glucose. Several EMs have shown culture times ranging between 15 and 40 d (Hutchison, 1991;Kuek, 1996;Rossi et al., 2017). However, unlike the 10 g/L treatments, in which cell death was detected in the last days of the culture, the 15 g/L treatments showed a lower biomass production, even when the microorganism reached its stationary phase (10 d in both flask morphologies) (Fig. 6). ...
In order to increase survival rates of greenhouse seedlings destined for restoration and conservation programs, successful mycorrhization of the seedlings is necessary. To reforest forest ecosystems, host trees must be inoculated with ectomycorrhizal fungi and, in order to guarantee a sufficient supply of ectomycorrhizal inoculum, it is necessary to develop technologies for the mass production of ectomycorrhizal fungi mycelia. We selected the ectomycorrhizal fungus Laccaria trichodermophora, due to its ecological traits and feasible mycelia production in asymbiotic conditions. Here, we report the field sampling of genetic resources, as well as the highly productive nutritional media and cultivation parameters in solid cultures. Furthermore, in order to achieve high mycelial production, we used strain screening and evaluated pH, carbon source concentration, and culture conditions of submerged cultures in normal and baffled shake flasks. The higher productivity culture conditions in shake flasks were selected for evaluation in a pneumatic bioreactor, using modified BAF media with a 10 g/L glucose, pH 5.5, 25 °C, and a volumetric oxygen transfer coefficient (KLa) of 36 h−1. Under those conditions less biomass (12–37 %) was produced in the pneumatic bioreactor compared with the baffled shake flasks. This approach shows that L. trichodermophora can generate a large biomass concentration and constitute the biotechnological foundation of its mycelia mass production.
... Due to the filamentous growing characteristics, ECM fungi need necessarily to be fragmented into smaller propagule pieces in every step of the scaling process, from the inoculum production to apply in the bioreactor (pre-production) to the inoculant bead production. These smaller propagules are important so there will be enough surface area to allow for mass transfer and to disperse the mycelium [10,11]. Still, fragmentation results in viability losses. ...
... Due to the filamentous growing characteristics, ECM fungi need necessarily to be fragmented into smaller propagule pieces in every step of the scaling process, from the inoculum production to apply in the bioreactor (pre-production) to the inoculant bead production. These smaller propagules are important so there will be enough surface area to allow for mass transfer and to disperse the mycelium [10,11]. Still, fragmentation results in viability losses. ...
Ectomycorrhizal fungi play an important role in promoting the growth and development of several tree species indispensable in worldwide forestation programs and, also, industrial processes. Yet, the large-scale production of ectomycorrhizal fungi necessary for these applications is still difficult and incipient. One alternative consists on the submerged cultivation of these fungi in high capacity bioreactors and the consequent production of inoculants by encapsulation. However, ectomycorhizal fungi present some limitations when growing under these conditions, and maintaining fungal viability is essential.In this work we studied the growth and viability of several of ectomycorhizal fungi such as, Rhizopogon, Pisolithus, Chondrogaster and Scleroderma spp. when subjected to submerged cultivation aiming for the production of large scale inocula, and tested the effect of activated charcoal in promoting fungal growth and viability. The results obtained showed that after fragmentation of mycelia, aiming for both inocula production for the application directly in the bioreactor or to the encapsulation process, most fungal isolates were unable to grow and maintain there viability when cultivated without charcoal. On the other hand, after fragmentation, activated charcoal increased the viability of the fragmented fungal mycelium, and also increased the fungal long term viability when encapsulated and stored under refrigerated conditions. Moreover, encapsulated ectomycorhizal fungi were able to efficiently colonize Eucalyptus plants. A model for the submerged cultivation and large scale commercial production of ectomycorrhizal fungi is therefore presented. Maximizing the growth and production of ectomycorrizal fungi may be the key for a wide range of agricultural and biotechnological applications worldwide.
Predicted famines due to population increase created an interest in the development of protein alternatives during the 1950s. Currently, a renewed interest in protein alternatives has developed as a potential strategy to decrease the environmental impact of protein production and meet the global demand for protein as the population increases. Fusarium venenatum A3/5/3, the organism used for mycoprotein production has been commercially available since the 1980s, however new fungal protein companies are currently interested in scaling up production. To aid guide efforts in this domain, we created an economic model with over 340 inputs that examines the continuous production of mycoprotein utilizing airlift bioreactors. Utilizing a sensitivity analysis, we identified critical processing inputs and then developed a user-friendly Excel model that allows for the exploration of customized production scenarios for interested stakeholders. Our findings indicate that mycoprotein can be cost competitive with beef on a price per protein basis. The findings also indicate that mycoprotein may not be an economically competitive alternative for other types of commodity meats (chicken) or for inexpensive meat-derived products (pet food) that utilize offal or meat byproducts not traditionally consumed in the modern western diet.
Liquid culture and solid culture fermentation are widely used to produce a range of metabolites. Despite the use of solid culture fermentation in some cases, most fermentations are carried out in a liquid broth. This type of production is called liquid state fermentation or submerged fermentation. Most fermentation processes are performed on aseptic conditions, with aeration and agitation, while some fermentations, such as beer and wine production, are carried out with no need of aseptic conditions, aeration, and agitation. This chapter will discuss liquid state fermentation principles.
