130
5.1
Introduction
Biotransformation or biocatalysis entails the use of the catalytic part of the biological systems such as plant cells, animal cells or microbial cells or purified enzymes
for the biosynthesis of novel compounds. Biotransformation has a high prospective
to bring about novel products and to improve known products more effectively. It
differs from biosynthesis and biodegradation in that it involves interconversion of
molecules by living systems, whereas biosynthesis is the combining of simpler substrates to form complex products and biodegradation is the decomposition of complex substances to simpler ones.
Biotransformation commonly occurs in human, plant and microbial cells as part
of metabolizing xenobiotics. Also, it serves as an efficient, specific, and eco-friendly
process for the production of industrial products, thereby replacing the toxic chemical transformation reactions. In many instances, chemical modification of compounds by biotransformation alters their biological effects, either making them
useful to the organism or ending up with toxic effects. But in most cases, biotransformation terminated with the production of propitious products.
Recent reviews suggest that biocatalysis also forms a sustainable way in environmental fields to mop up environmental pollutants. It helps harness the catabolic
activity of living systems to degrade and transform a wide range of compounds to
chirally pure compounds, thereby offering several advantages over the use of chemicals and microorganisms. Thus, biotransforming enzymes are gaining importance.
Properties of biotransforming enzymes are as follows:
• Biocatalysis, which is normally performed in an aqueous environment but can, in
many cases, also be conducted in solvent mixtures, liquid–liquid two-phase systems, and even in pure organic solvents. A relevant practical example is the use
of esterases and lipases to catalyse esterifications in organic solvents such as
vinyl acetate.
• They require mild reaction conditions. Therefore, biocatalysis offers great
chances and advantages for successful applications (also in cases where either
the substrates or the products of the reaction are chemically labile).
• There is no, or only limited, use of protecting groups, for example, for the chemoenzymatic synthesis of complex carbohydrates and glycoconjugates.
• They have high chemo-, regio- and stereoselectivities (Oreste Ghisalba et al.
2010).
A wide variety of biotransforming enzymes exist and are highly substrate specific. Some of the biotransforming enzymes are similar in plants, animals and in
humans but there are a few species specific ones. In this context, we can classify the
biotransformation enzymes into three as occurring in humans, plants and microbial
cells.
S. Sudhakaran et al.
5.1
Introduction
Biotransformation or biocatalysis entails the use of the catalytic part of the biological systems such as plant cells, animal cells or microbial cells or purified enzymes
for the biosynthesis of novel compounds. Biotransformation has a high prospective
to bring about novel products and to improve known products more effectively. It
differs from biosynthesis and biodegradation in that it involves interconversion of
molecules by living systems, whereas biosynthesis is the combining of simpler substrates to form complex products and biodegradation is the decomposition of complex substances to simpler ones.
Biotransformation commonly occurs in human, plant and microbial cells as part
of metabolizing xenobiotics. Also, it serves as an efficient, specific, and eco-friendly
process for the production of industrial products, thereby replacing the toxic chemical transformation reactions. In many instances, chemical modification of compounds by biotransformation alters their biological effects, either making them
useful to the organism or ending up with toxic effects. But in most cases, biotransformation terminated with the production of propitious products.
Recent reviews suggest that biocatalysis also forms a sustainable way in environmental fields to mop up environmental pollutants. It helps harness the catabolic
activity of living systems to degrade and transform a wide range of compounds to
chirally pure compounds, thereby offering several advantages over the use of chemicals and microorganisms. Thus, biotransforming enzymes are gaining importance.
Properties of biotransforming enzymes are as follows:
• Biocatalysis, which is normally performed in an aqueous environment but can, in
many cases, also be conducted in solvent mixtures, liquid–liquid two-phase systems, and even in pure organic solvents. A relevant practical example is the use
of esterases and lipases to catalyse esterifications in organic solvents such as
vinyl acetate.
• They require mild reaction conditions. Therefore, biocatalysis offers great
chances and advantages for successful applications (also in cases where either
the substrates or the products of the reaction are chemically labile).
• There is no, or only limited, use of protecting groups, for example, for the chemoenzymatic synthesis of complex carbohydrates and glycoconjugates.
• They have high chemo-, regio- and stereoselectivities (Oreste Ghisalba et al.
2010).
A wide variety of biotransforming enzymes exist and are highly substrate specific. Some of the biotransforming enzymes are similar in plants, animals and in
humans but there are a few species specific ones. In this context, we can classify the
biotransformation enzymes into three as occurring in humans, plants and microbial
cells.
S. Sudhakaran et al.