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25 Nanobiotechnology – A Green Solution

needs strict maintenance of purity; repetition of preprocessing, processing, and

post processing of steps in a single batch operation, yet the yield being low; use of

toxic and hazardous chemicals, use or generation of greenhouse gases; generation

of wastes associated with top-down techniques are some of the associated problems

with the conventional procedures of the technology. Waste reduction can be

achieved by adopting eco-friendly synthesis procedures of a biological nature. Here

comes the application of green nanobiotechnology that applies biological routes

involving microorganisms, viruses, plant, and their products like proteins and

lipids with the aid of different biotechnological tools. The bio-based synthesis of

nanoparticles utilizes mostly a bottom-up approach where due considerations are

given in the selection of solvent medium, a “green” reducing agent, i.e. it should be

eco-friendly and a nontoxic capping agent for the stabilization of the nanoparticles.

Since the method makes use of plant extracts, industrial and agricultural wastes,

enzymes and biomolecules, microorganisms, e.g. bacteria, fungi, algae, seaweeds,

etc. Thus, the technology is not only “green” but also contributes significantly to

waste reduction by reuse of wastes in many cases [5, 7, 9].

25.2.1

Green Chemistry

Though green nanotechnology and nanobiotechnology are the major focus of

discussion in this chapter; however, the significant role of “green chemistry” in

“zero waste economy” also needs to be highlighted. The 12 principles of green

chemistry, as postulated by Paul Anastas and John Warner in 1990s (Table 25.1),

emphasized on reduction or rather elimination of use of toxic solvents, avoidance of

synthetic procedures, and analytical techniques generating hazardous byproducts.

Green chemistry aims to attain a “green and clean earth” and synonymously also

known as “clean chemistry,” “eco-friendly chemistry,” “environmentally benign

chemistry,” “sustainable chemistry,” “atom economy,” “e-chemistry,” etc. The

green chemical approach is not only eco-friendly and holistic in nature but aims

to synthesize or utilize the products in an eco-friendly manner and finally reduce

waste production. The subject encompasses a broad domain of major branches of

chemical sciences, viz. organic and inorganic synthesis, material science, polymer

chemistry, nanochemistry, supramolecular chemistry, and so on [10–14]. The 12

principles of green chemistry (Table 25.1) stresses on waste prevention rather than

its further treatment or clean-up; use of renewable starting materials with minimal

energy expenditure, and reducing the use of auxillary substances and chemically

synthesizing nontoxic, nonhazardous, environmentally benign substances. [10–14].

Here it is to be mentioned that green chemistry is totally different from environmen-

tal chemistry as the later emphasizes on pollution and the methods of prevention.

But green chemistry focuses on the elimination of pollution from the beginnings.

If “prevention is better than cure.” green chemistry is the preventive pathway, and

environmental chemistry is the curative pathway [10–14].

Samantha Tang, Richard Bourne, Richard Smith, and Martyn Poliakoff sug-

gested a condensed 24 Principles of Green Chemistry and Green Engineering,

with the mnemonic “IMPROVEMENTS PRODUCTIVELY.” Here the word