13.2.2 Fungi: Bioremediation of Radioactive Wastes
Fungi play an essential role in soil food web as it decomposes various organic
substances. Fungi is able to decompose woods by degrading the key components of
wood fibre such as lignin and cellulose (Hildén and Mäkelä 2018). Fungi also
showed efficient results in bioremediation of dyes, heavy metals released from
textile industries, pharmaceutical industries, etc. (Khan et al. 2019). The environment radioactive waste contaminated sites have low pH, high temperature and
extreme radiations, and it seems to be impossible to survive any species at that
extreme condition. Therefore, for bioremediation purpose, it is essential to search the
microbes which is able to survive under extreme environmental conditions
(Fredrickson et al. 2004). Tkavc et al. isolated Rhodotorula taiwanensis MD1149,
a fungal species which can survive under environmentally harsh condition,
i.e. highly acidic condition at pH 2.3, high metal concentration and extreme radiation. The fungi showed bio-film formation under extreme gamma radiation and at
low pH (Tkavc et al. 2018).
Fungi Rhizopus arrhizus along with the immobilized particles showed
biosorption of uranium from bioleaching uranium ore solutions. The amine nitrogen
of chitin along with free radicals results uranium biosorption (Gadd and Fomina
2011). The carboxyl and phosphates group of Saccharomyces cerevisiae cell wall
showed initial uranium deposition (Zhang et al. 2020). pH also plays a major role in
biosorption of radionuclides. For examples, at pH 3 Mucor miehei sorbs 70–80 mg
uranium/g dry weight of fungi, and at pH 4 and 5, the biosorption increases 2–3
times, respectively. While Rhizopus sp. showed efficient Cr(VI) adsorption at pH 2.0
(Espinoza-Sánchez et al. 2019; Gadd and Fomina 2011). The crystalline disposition
of uranium was observed in Penicillium digitatum (Gadd and Fomina 2011).
In the field of bioremediation, mushroom plays a key role. Due to the large
fruiting bodies, mushroom gains much attention that it can accumulate large amount
of wastes. Mushroom has the ability to degrade, decompose and accumulate different types of organic wastes and agro wastes (Pandey et al. 2018). But in the field of
radioactive waste bioremediation, mushroom was less studied. Baeza and Guillén
(2006) studied the uranium bioaccumulation in mushrooms, and they determined it
in terms of transfer factor (TF), i.e. level of radioactivity is detected in mushrooms in
comparison to surface soil. They found that Amanita muscaria and Hebeloma
cylindrosporum showed the highest TF values while Lactarius deliciosus exhibited
the least ranges from 0.043 to 0.49 (Baeza et al. 2004).
13.2.3 Algae: Bioremediation of Radioactive Wastes
Like bacteria and fungi, algae also play crucial role in bioremediation of various
pollutants like heavy metals and other organic pollutants. Algal-based bioremediation is known as phycoremediation. Due to autotrophic in nature, algal
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U. K. Vandana et al.
Fungi play an essential role in soil food web as it decomposes various organic
substances. Fungi is able to decompose woods by degrading the key components of
wood fibre such as lignin and cellulose (Hildén and Mäkelä 2018). Fungi also
showed efficient results in bioremediation of dyes, heavy metals released from
textile industries, pharmaceutical industries, etc. (Khan et al. 2019). The environment radioactive waste contaminated sites have low pH, high temperature and
extreme radiations, and it seems to be impossible to survive any species at that
extreme condition. Therefore, for bioremediation purpose, it is essential to search the
microbes which is able to survive under extreme environmental conditions
(Fredrickson et al. 2004). Tkavc et al. isolated Rhodotorula taiwanensis MD1149,
a fungal species which can survive under environmentally harsh condition,
i.e. highly acidic condition at pH 2.3, high metal concentration and extreme radiation. The fungi showed bio-film formation under extreme gamma radiation and at
low pH (Tkavc et al. 2018).
Fungi Rhizopus arrhizus along with the immobilized particles showed
biosorption of uranium from bioleaching uranium ore solutions. The amine nitrogen
of chitin along with free radicals results uranium biosorption (Gadd and Fomina
2011). The carboxyl and phosphates group of Saccharomyces cerevisiae cell wall
showed initial uranium deposition (Zhang et al. 2020). pH also plays a major role in
biosorption of radionuclides. For examples, at pH 3 Mucor miehei sorbs 70–80 mg
uranium/g dry weight of fungi, and at pH 4 and 5, the biosorption increases 2–3
times, respectively. While Rhizopus sp. showed efficient Cr(VI) adsorption at pH 2.0
(Espinoza-Sánchez et al. 2019; Gadd and Fomina 2011). The crystalline disposition
of uranium was observed in Penicillium digitatum (Gadd and Fomina 2011).
In the field of bioremediation, mushroom plays a key role. Due to the large
fruiting bodies, mushroom gains much attention that it can accumulate large amount
of wastes. Mushroom has the ability to degrade, decompose and accumulate different types of organic wastes and agro wastes (Pandey et al. 2018). But in the field of
radioactive waste bioremediation, mushroom was less studied. Baeza and Guillén
(2006) studied the uranium bioaccumulation in mushrooms, and they determined it
in terms of transfer factor (TF), i.e. level of radioactivity is detected in mushrooms in
comparison to surface soil. They found that Amanita muscaria and Hebeloma
cylindrosporum showed the highest TF values while Lactarius deliciosus exhibited
the least ranges from 0.043 to 0.49 (Baeza et al. 2004).
13.2.3 Algae: Bioremediation of Radioactive Wastes
Like bacteria and fungi, algae also play crucial role in bioremediation of various
pollutants like heavy metals and other organic pollutants. Algal-based bioremediation is known as phycoremediation. Due to autotrophic in nature, algal
344
U. K. Vandana et al.