Microbial-Mediated Nanoparticles for Sustainable Environment …
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greener synthesis of NPs. Their capacity is unmatched in case of generation of
different types of biologically active substances containing higher proteinaceous
content. Although these nano-biofactories are capable of production of NPs in both
extracellular and intracellular modes, however, extracellular reduction has been the
most frequently adopted pathway possessing a multitude of applications in varied
commercial fields. Actinobacterium Rhodococcus NCIM 2891 has been used by
Otari et al. (2012) for the synthesis of AgNPs having spherical shape possessing
10 nm size. The results were indicative of the bio-mineralization of Ag
+ in an intracellular mode resulting from cell wall enzymatic substances leading to formation
of Ag nuclei. In another report, Streptomyces sp. LK-3, having a marine origin was
used for green synthesis of AgNPs (Karthik et al. 2014).
Yeast cells have also been used for the biogenic synthesis of metallic NPs by the
virtue of the inherent potential of absorption and accumulation in higher quantities of
toxic metallic ions from their immediate ambience (Shah et al. 2015). They are also
known for adaptation toward metal toxicity circumstances by utilization of varied
detoxifying mechanistic routes, e.g., bio-precipitative mechanisms, chelation, and
sequestration in intracellular mode. Such an extraordinary combating potential of
yeasts has been used by different scientific groups. For instance, Yarrowia lipolytica having a marine genesis and is ascomycetous yeast strain has been used for the
biogenic synthesis of Ag NPs in a cell concomitant way (Apte et al. 2013). Results
for Yarrowia lipolytica-based AgNPs were suggestive of the melanin to be an influential factor in causing bio-mineralization of the metallic ions. Furthermore, the
melanin pigment-based AgNPs expressed a remarkable antibiofilm activity toward
Salmonella paratyphi.
Interestingly, the borderline between living and non-living organisms, i.e., viruses,
has also been employed in the sustainable synthesis of biomimetic NPs in a sustainable and cost-effective manner as per their thicker external surficial coating of the
capsid proteinaceous substances associated with the providence of the remarkably
favorable media for reaction between viruses and metallic ions (Kobayashi et al.
2012). By means of incorporating techniques of genetic engineering, the protein
cages of viruses can be made into monodispersed entities having considerable
strength and ability to be transformed in any manner. Thus, this type of modification has made them a template for biogenic synthesis. More specifically, they can
be used for the deposition of different materials or can be precisely engineered for
the creation of three-dimensional receptacles aimed at drug delivery (Zeng et al.
2013). In the same manner, they can be effectively made use of for the development of different types of conjugates and composites in nano-regime with metallic
NPs having a profound significance in the drug delivery and therapy of cancer. In
this regard, Mao et al. (2003) has reported the utilization of M13 bacteriophage
focused at the semiconductor nanocrystals undergoing the process of nucleation and
positioning.
299
greener synthesis of NPs. Their capacity is unmatched in case of generation of
different types of biologically active substances containing higher proteinaceous
content. Although these nano-biofactories are capable of production of NPs in both
extracellular and intracellular modes, however, extracellular reduction has been the
most frequently adopted pathway possessing a multitude of applications in varied
commercial fields. Actinobacterium Rhodococcus NCIM 2891 has been used by
Otari et al. (2012) for the synthesis of AgNPs having spherical shape possessing
10 nm size. The results were indicative of the bio-mineralization of Ag
+ in an intracellular mode resulting from cell wall enzymatic substances leading to formation
of Ag nuclei. In another report, Streptomyces sp. LK-3, having a marine origin was
used for green synthesis of AgNPs (Karthik et al. 2014).
Yeast cells have also been used for the biogenic synthesis of metallic NPs by the
virtue of the inherent potential of absorption and accumulation in higher quantities of
toxic metallic ions from their immediate ambience (Shah et al. 2015). They are also
known for adaptation toward metal toxicity circumstances by utilization of varied
detoxifying mechanistic routes, e.g., bio-precipitative mechanisms, chelation, and
sequestration in intracellular mode. Such an extraordinary combating potential of
yeasts has been used by different scientific groups. For instance, Yarrowia lipolytica having a marine genesis and is ascomycetous yeast strain has been used for the
biogenic synthesis of Ag NPs in a cell concomitant way (Apte et al. 2013). Results
for Yarrowia lipolytica-based AgNPs were suggestive of the melanin to be an influential factor in causing bio-mineralization of the metallic ions. Furthermore, the
melanin pigment-based AgNPs expressed a remarkable antibiofilm activity toward
Salmonella paratyphi.
Interestingly, the borderline between living and non-living organisms, i.e., viruses,
has also been employed in the sustainable synthesis of biomimetic NPs in a sustainable and cost-effective manner as per their thicker external surficial coating of the
capsid proteinaceous substances associated with the providence of the remarkably
favorable media for reaction between viruses and metallic ions (Kobayashi et al.
2012). By means of incorporating techniques of genetic engineering, the protein
cages of viruses can be made into monodispersed entities having considerable
strength and ability to be transformed in any manner. Thus, this type of modification has made them a template for biogenic synthesis. More specifically, they can
be used for the deposition of different materials or can be precisely engineered for
the creation of three-dimensional receptacles aimed at drug delivery (Zeng et al.
2013). In the same manner, they can be effectively made use of for the development of different types of conjugates and composites in nano-regime with metallic
NPs having a profound significance in the drug delivery and therapy of cancer. In
this regard, Mao et al. (2003) has reported the utilization of M13 bacteriophage
focused at the semiconductor nanocrystals undergoing the process of nucleation and
positioning.