Over the past decade, the combination of multiple (bio)catalytic steps onto
each other in a cascade [27, 28] has resulted in the design of ‘artificial synthetic
pathways’, which show drastically improved efficiency compared to traditional
step-wise synthesis, because decomposition of sensitive intermediates is minimized
and loss-causing purification of intermediates is omitted.
After all, enzymes have been optimizing their skills for more than 3 Â 10
9 years
so as to develop a lot of sophisticated chemistry, whereas organic chemists and
genetic engineers have a track record of less than a century. There is strong
evidence that the number of distinctly different enzyme mechanisms is finite,
since we know examples of protein molecules that are unrelated by evolution but
possess almost identically arranged functional groups. In many cases, Nature has
obviously faced the same biochemical problem and has found the same optimum
solution. In parallel to the development of novel enzymes by evolution through
natural selection, tremendous advances in the field of genetic engineering provide
biocatalysts at drastically decreased costs, and also allow the design of enzymes
possessing enhanced stabilities and altered (stereo)specificities.
Most of the environmental contamination of greatest concern involves xenobiotic materials which have been produced and distributed over our globe with
increasing diversity and volume in industrial and agricultural processes during the
past century. These include hydrocarbons, heavy metals, neurotoxic pesticides,
halogenated (aromatic) compounds, explosives, and carcinogens, which often do
not have natural counterparts. Although their introduction into the ecosphere is
lamentable, and the effects they can have on the environment is often devastating,
numerous microbial systems have already acquired the ability to degrade most of
these xenobiotics. The likelihood that totally new enzymes with specific detoxification activities could evolve naturally in such a brief period of time is unrealistic, it
is more likely that enzymes already present in microbial communities – used for
defense and maintenance functions – were evolutionary adapted within a few
decades through chemical stress to address the new challenge. These novel biocatalytic activities represent a large potential to enable the transformation of functional
groups, which are unknown to biochemistry.
The enormous amount of ~9.5 Gt
2 of carbon derived from non-renewable fossil
resources – oil, coal and natural gas – are currently converted annually worldwide.
Only a small fraction (~5–9%) of this precious raw material is used as starting
material for the synthesis of organic compounds, such as polymers, dyes, detergents, pharmaceuticals, vitamins, etc., which make our high-tech life safe, healthy
and comfortable. The vast majority of it (>90 %) is burnt to generate energy going
in hand with an undesired accumulation of CO 2 in the atmosphere, where it
accelerates global warming [29].
3
2 BP Statistical Report 2017
3 World primary energy patterns are changing only slowly: Currently, oil constitutes 35% of
global energy consumption, coal 29%, natural gas 24%, nuclear power 5.5% and hydroelectricity
6.6%.
4 State of the Art and Outlook
411
each other in a cascade [27, 28] has resulted in the design of ‘artificial synthetic
pathways’, which show drastically improved efficiency compared to traditional
step-wise synthesis, because decomposition of sensitive intermediates is minimized
and loss-causing purification of intermediates is omitted.
After all, enzymes have been optimizing their skills for more than 3 Â 10
9 years
so as to develop a lot of sophisticated chemistry, whereas organic chemists and
genetic engineers have a track record of less than a century. There is strong
evidence that the number of distinctly different enzyme mechanisms is finite,
since we know examples of protein molecules that are unrelated by evolution but
possess almost identically arranged functional groups. In many cases, Nature has
obviously faced the same biochemical problem and has found the same optimum
solution. In parallel to the development of novel enzymes by evolution through
natural selection, tremendous advances in the field of genetic engineering provide
biocatalysts at drastically decreased costs, and also allow the design of enzymes
possessing enhanced stabilities and altered (stereo)specificities.
Most of the environmental contamination of greatest concern involves xenobiotic materials which have been produced and distributed over our globe with
increasing diversity and volume in industrial and agricultural processes during the
past century. These include hydrocarbons, heavy metals, neurotoxic pesticides,
halogenated (aromatic) compounds, explosives, and carcinogens, which often do
not have natural counterparts. Although their introduction into the ecosphere is
lamentable, and the effects they can have on the environment is often devastating,
numerous microbial systems have already acquired the ability to degrade most of
these xenobiotics. The likelihood that totally new enzymes with specific detoxification activities could evolve naturally in such a brief period of time is unrealistic, it
is more likely that enzymes already present in microbial communities – used for
defense and maintenance functions – were evolutionary adapted within a few
decades through chemical stress to address the new challenge. These novel biocatalytic activities represent a large potential to enable the transformation of functional
groups, which are unknown to biochemistry.
The enormous amount of ~9.5 Gt
2 of carbon derived from non-renewable fossil
resources – oil, coal and natural gas – are currently converted annually worldwide.
Only a small fraction (~5–9%) of this precious raw material is used as starting
material for the synthesis of organic compounds, such as polymers, dyes, detergents, pharmaceuticals, vitamins, etc., which make our high-tech life safe, healthy
and comfortable. The vast majority of it (>90 %) is burnt to generate energy going
in hand with an undesired accumulation of CO 2 in the atmosphere, where it
accelerates global warming [29].
3
2 BP Statistical Report 2017
3 World primary energy patterns are changing only slowly: Currently, oil constitutes 35% of
global energy consumption, coal 29%, natural gas 24%, nuclear power 5.5% and hydroelectricity
6.6%.
4 State of the Art and Outlook
411