404
A. P. Ingle et al.
2.3 Algal Synthesis
Similar to various above-mentioned microbial systems, algae also have some advantages over other biological processes because it is easy to produce nanoparticles on
large scale using algae as bulk biomass of algae can be produced easily. To date,
more than a hundred different micro- and macro-algae have been used for both
intracellular and extracellular synthesis of nanoparticles (Dhavale et al. 2020). The
synthesis of AgNPs was demonstrated using cell free extract of green alga Chlorella
vulgaris (Xie et al. 2007). Similarly, Vivek et al. (2011) found that a red alga Gelidiella acerosa has ability to reduce aqueous silver ions into spherical AgNPs with
an average size of 22 nm. In another study, Tsibakhashvili et al. (2011) studied
the extracellular synthesis of AgNPs using extract of Spirulina platensis. Moreover,
Abdel-Raouf et al. (2019) reported synthesis of AgNPs by the reduction of aqueous
solutions of silver nitrate using powder and solvent extracts of Padina pavonica.
The results revealed that the used algae has promising potential in the synthesis of
AgNPs producing 49.58–86.37 nm sized particles of variable shapes i.e. spherical,
triangular, rectangle, polyhedral and hexagonal. More recently, Nannochloropsis sp,
Chlorella vulgaris, and Neodesmus pupukensis have been employed to synthesize
AgNPs for antimicrobial, antioxidant, and bioremediation applications (Adenigba
et al. 2020; Omomowo et al. 2020).
Algae are well known for their ability to hyperaccumulate heavy metal ions and
possess an excellent capability to modify them into more malleable forms (Fawcett
et al. 2017). Due to these abilities, algae have attracted a considerable attention from
scientific community and being used as model microbial system for the synthesis of
bio-nanomaterials. The extract of algae usually consists of carbohydrates, proteins,
minerals, oil, fats, polyunsaturated fatty acids, and other bioactive compounds such as
antioxidants (polyphenols, tocopherols), and pigments such ascarotenoids (carotene,
xanthophyll), chlorophylls, and phycobilins (phycocyanin, phycoerythrin) (Michalak
and Chojnacka 2015; Khanna et al. 2019). These active compounds act as reducing
and stabilizing agents during the synthesis of nanoparticles.
2.4 Synthesis from Cyanobacteria
Cyanobacteria have recently been a wise choice for mediating nanoparticles synthesis
as they are capable of bio-remediating toxic metals and further convert them into
attractive and amenable products (Ebrahimzadeh et al. 2020). One advantageous
aspect of this utilization is the simple nutrient media required by those types of
organisms and can easily be cultivated in large scale (Yu et al. 2013). In alignment with the emerging trend of anticancer activity provided specifically by AgNPs,
Ebrahhimzadeh and co-workers guided a study of green synthesis of AgNPs through
Anabaena flos-aquae which is a simple, rapid, inexpensive, and ecofriendly manner
to achieve the target. In their work, cytotoxicity tests against human breast cancer
A. P. Ingle et al.
2.3 Algal Synthesis
Similar to various above-mentioned microbial systems, algae also have some advantages over other biological processes because it is easy to produce nanoparticles on
large scale using algae as bulk biomass of algae can be produced easily. To date,
more than a hundred different micro- and macro-algae have been used for both
intracellular and extracellular synthesis of nanoparticles (Dhavale et al. 2020). The
synthesis of AgNPs was demonstrated using cell free extract of green alga Chlorella
vulgaris (Xie et al. 2007). Similarly, Vivek et al. (2011) found that a red alga Gelidiella acerosa has ability to reduce aqueous silver ions into spherical AgNPs with
an average size of 22 nm. In another study, Tsibakhashvili et al. (2011) studied
the extracellular synthesis of AgNPs using extract of Spirulina platensis. Moreover,
Abdel-Raouf et al. (2019) reported synthesis of AgNPs by the reduction of aqueous
solutions of silver nitrate using powder and solvent extracts of Padina pavonica.
The results revealed that the used algae has promising potential in the synthesis of
AgNPs producing 49.58–86.37 nm sized particles of variable shapes i.e. spherical,
triangular, rectangle, polyhedral and hexagonal. More recently, Nannochloropsis sp,
Chlorella vulgaris, and Neodesmus pupukensis have been employed to synthesize
AgNPs for antimicrobial, antioxidant, and bioremediation applications (Adenigba
et al. 2020; Omomowo et al. 2020).
Algae are well known for their ability to hyperaccumulate heavy metal ions and
possess an excellent capability to modify them into more malleable forms (Fawcett
et al. 2017). Due to these abilities, algae have attracted a considerable attention from
scientific community and being used as model microbial system for the synthesis of
bio-nanomaterials. The extract of algae usually consists of carbohydrates, proteins,
minerals, oil, fats, polyunsaturated fatty acids, and other bioactive compounds such as
antioxidants (polyphenols, tocopherols), and pigments such ascarotenoids (carotene,
xanthophyll), chlorophylls, and phycobilins (phycocyanin, phycoerythrin) (Michalak
and Chojnacka 2015; Khanna et al. 2019). These active compounds act as reducing
and stabilizing agents during the synthesis of nanoparticles.
2.4 Synthesis from Cyanobacteria
Cyanobacteria have recently been a wise choice for mediating nanoparticles synthesis
as they are capable of bio-remediating toxic metals and further convert them into
attractive and amenable products (Ebrahimzadeh et al. 2020). One advantageous
aspect of this utilization is the simple nutrient media required by those types of
organisms and can easily be cultivated in large scale (Yu et al. 2013). In alignment with the emerging trend of anticancer activity provided specifically by AgNPs,
Ebrahhimzadeh and co-workers guided a study of green synthesis of AgNPs through
Anabaena flos-aquae which is a simple, rapid, inexpensive, and ecofriendly manner
to achieve the target. In their work, cytotoxicity tests against human breast cancer