6
upon the nature of substrate involved, the fermentation process producing the fungal
biomass could be submerged fermentation or solid state fermentation. As mentioned
above, the type of substrate is a pivotal factor from economic as well as from yield
point of view. As many agro-industrial based-wastewaters are used as substrates,
few more components must be added to the media to meet the nutritional demands
of the fungi. The important components include carbon source, nitrogen source, and
some other salts. Nitrogen in the media will regulate the pH conditions. Hence, its
concentration should be accurate. Carbon source must be rich in cellulosic material
during the fermentation process. But since cellulosic material is used, some kind of
pretreatment must be required in order to make these nutrients available to the fungi
(Hultberg and Bodin 2017).
Many studies have been conducted where researchers have used a variety of different substrates for the production of fungal biomass. One such study demonstrated
the use of fungi Trichoderma harzianum for the production of fungal biomass. The
substrate used was polished rice and it was found that the biomass produced maximum yield of 5% (w/v) and was rich in protein content with the presence of essential amino acids (Ahmed et al. 2017). Another study involved the combination of
three white rot fungi for the production of fungal biomass through the process of
fermentation. The substrates were also used in combination. The substrates chosen
were from the agro-industrial wastes, i.e., fruit peels. In this study, they used pineapple, banana, and papaya peels. The fungi were inoculated and after fermentation
and harvesting, the amount of fungal biomass obtained was measured (Saheed et al.
2016). Moreover, some used another type of fungi for high yield production of fungal biomass. Another study was done where researchers used various strains of
Morchella species with the combination of substrates that were rich in starch. The
substrates consumed were wheat grains and potato peels. The resulting biomass had
high polysaccharide content with high yield (Papadaki et al. 2019).
Once the fungal biomass is produced, these fungal proteins were extracted and
converted to more processed forms. The most common form in which these fungal
biomass proteins are consumed nowadays is mycoprotein. Mycoproteins are also
known by their other name – Quorn. The most common fungi used for mycoprotein
production is Fusarium venenatum (Park et al. 2017). The usual and very first protocol for the production of this mycoprotein involves the inoculation of fungus into
the glucose-containing media and with other controlled parameters. The incubation
is carried out until a desired amount of circulating solids is formed into the air-lift
fermenters. Once the solid mass is formed, the material is subjected to various sessions of heating so that RNA gets inactivated which is further removed from the
cells through diffusion. The remaining solid mass is subjected to centrifugation so
that clarification can be done. The last step is to perform the vacuum chilling and
finally mycoprotein gets ready. But this protein further needs to get processed for its
use as an edible component. Since the mycoprotein produced lacks elasticity, it was
mixed with some common binding agents like egg albumin, water, or some other
extracts. These binding agents are then mixed completely, and this modified mycoprotein mass is subjected to heating so that the egg proteins denature. After this, the
modified mycoproteins are pressed in order to give them block or cube shapes and
S. Singh and S. Gaur
upon the nature of substrate involved, the fermentation process producing the fungal
biomass could be submerged fermentation or solid state fermentation. As mentioned
above, the type of substrate is a pivotal factor from economic as well as from yield
point of view. As many agro-industrial based-wastewaters are used as substrates,
few more components must be added to the media to meet the nutritional demands
of the fungi. The important components include carbon source, nitrogen source, and
some other salts. Nitrogen in the media will regulate the pH conditions. Hence, its
concentration should be accurate. Carbon source must be rich in cellulosic material
during the fermentation process. But since cellulosic material is used, some kind of
pretreatment must be required in order to make these nutrients available to the fungi
(Hultberg and Bodin 2017).
Many studies have been conducted where researchers have used a variety of different substrates for the production of fungal biomass. One such study demonstrated
the use of fungi Trichoderma harzianum for the production of fungal biomass. The
substrate used was polished rice and it was found that the biomass produced maximum yield of 5% (w/v) and was rich in protein content with the presence of essential amino acids (Ahmed et al. 2017). Another study involved the combination of
three white rot fungi for the production of fungal biomass through the process of
fermentation. The substrates were also used in combination. The substrates chosen
were from the agro-industrial wastes, i.e., fruit peels. In this study, they used pineapple, banana, and papaya peels. The fungi were inoculated and after fermentation
and harvesting, the amount of fungal biomass obtained was measured (Saheed et al.
2016). Moreover, some used another type of fungi for high yield production of fungal biomass. Another study was done where researchers used various strains of
Morchella species with the combination of substrates that were rich in starch. The
substrates consumed were wheat grains and potato peels. The resulting biomass had
high polysaccharide content with high yield (Papadaki et al. 2019).
Once the fungal biomass is produced, these fungal proteins were extracted and
converted to more processed forms. The most common form in which these fungal
biomass proteins are consumed nowadays is mycoprotein. Mycoproteins are also
known by their other name – Quorn. The most common fungi used for mycoprotein
production is Fusarium venenatum (Park et al. 2017). The usual and very first protocol for the production of this mycoprotein involves the inoculation of fungus into
the glucose-containing media and with other controlled parameters. The incubation
is carried out until a desired amount of circulating solids is formed into the air-lift
fermenters. Once the solid mass is formed, the material is subjected to various sessions of heating so that RNA gets inactivated which is further removed from the
cells through diffusion. The remaining solid mass is subjected to centrifugation so
that clarification can be done. The last step is to perform the vacuum chilling and
finally mycoprotein gets ready. But this protein further needs to get processed for its
use as an edible component. Since the mycoprotein produced lacks elasticity, it was
mixed with some common binding agents like egg albumin, water, or some other
extracts. These binding agents are then mixed completely, and this modified mycoprotein mass is subjected to heating so that the egg proteins denature. After this, the
modified mycoproteins are pressed in order to give them block or cube shapes and
S. Singh and S. Gaur