10.1 Introduction
The sentences quoted above were taken from a lecture entitled “Eenheid en
verscheidenheid in de stofwisseling der microben” (Unity and diversity in the
metabolism of the microbes), delivered by Albert Jan Kluyver at the general
assembly of the Netherlands Chemical Society in April 1924. Kluyver is wellknown for his concept of the unity in biochemistry (Kluyver and Donker 1926).
Indeed, the general unifying principles that Kluyver identified, as expressed in his
famous saying “From elephant to butyric acid bacterium—it is all the same!” still
hold today. Many of the ideas exposed in his famous paper of 1926 can be found in
the text of the lecture he gave 2 years earlier.
There can be no doubt that the greatest metabolic diversity is found in the
prokaryotic world. Since the days of Sergei Winogradsky and Martinus Beijerinck
who identified many novel ways in which bacteria can make a living, it is obvious
that archaea and bacteria exploit many modes of energy generation that do not exist
in the eukaryotic world. One could almost say that, as long as a chemical reaction
based on compounds available in nature is sufficiently exergonic, some microbe can
be found that will derive its energy from it. Chemical thermodynamics sets the
limits. Kluyver was obviously fascinated by this “grand microbial variety show.” His
own studies on different processes of fermentation, anaerobic respiration, and
methanogenesis, as well as many other discoveries of new types of metabolism
identified by others in the first decades of the twentieth century, urged him to search
for the unifying principles behind the metabolic diversity.
My personal fascination with the metabolic diversity displayed by the microorganisms made me decide to devote my career to the study of the prokaryotic world. It
happened that my first microbiology teacher was Hans Veldkamp, who had spent
part of this time as a student in Albert Jan Kluyver’s laboratory (Konings and
Kuenen 2003). When today I compare our knowledge of the metabolic diversity
of the prokaryotes with what we knew when I started my studies in the early 1970s, I
am amazed how many novel processes were discovered, especially in the last two
decades. Many old dogmas about the apparent limits of what microbes can do were
upended. Textbooks had to be updated and rewritten to include the often major
contributions made by hitherto unknown processes to the global cycles of carbon,
nitrogen, sulfur, and phosphorus. Still, the basic principle of the unity in biochemistry holds true. In this chapter, I present a personal selection of newly discovered
ways used by prokaryotes to obtain energy and carbon for growth, all exciting new
microbial “acts” that can be added to Kluyver’s microbial “variety show.”
162
A. Oren
The sentences quoted above were taken from a lecture entitled “Eenheid en
verscheidenheid in de stofwisseling der microben” (Unity and diversity in the
metabolism of the microbes), delivered by Albert Jan Kluyver at the general
assembly of the Netherlands Chemical Society in April 1924. Kluyver is wellknown for his concept of the unity in biochemistry (Kluyver and Donker 1926).
Indeed, the general unifying principles that Kluyver identified, as expressed in his
famous saying “From elephant to butyric acid bacterium—it is all the same!” still
hold today. Many of the ideas exposed in his famous paper of 1926 can be found in
the text of the lecture he gave 2 years earlier.
There can be no doubt that the greatest metabolic diversity is found in the
prokaryotic world. Since the days of Sergei Winogradsky and Martinus Beijerinck
who identified many novel ways in which bacteria can make a living, it is obvious
that archaea and bacteria exploit many modes of energy generation that do not exist
in the eukaryotic world. One could almost say that, as long as a chemical reaction
based on compounds available in nature is sufficiently exergonic, some microbe can
be found that will derive its energy from it. Chemical thermodynamics sets the
limits. Kluyver was obviously fascinated by this “grand microbial variety show.” His
own studies on different processes of fermentation, anaerobic respiration, and
methanogenesis, as well as many other discoveries of new types of metabolism
identified by others in the first decades of the twentieth century, urged him to search
for the unifying principles behind the metabolic diversity.
My personal fascination with the metabolic diversity displayed by the microorganisms made me decide to devote my career to the study of the prokaryotic world. It
happened that my first microbiology teacher was Hans Veldkamp, who had spent
part of this time as a student in Albert Jan Kluyver’s laboratory (Konings and
Kuenen 2003). When today I compare our knowledge of the metabolic diversity
of the prokaryotes with what we knew when I started my studies in the early 1970s, I
am amazed how many novel processes were discovered, especially in the last two
decades. Many old dogmas about the apparent limits of what microbes can do were
upended. Textbooks had to be updated and rewritten to include the often major
contributions made by hitherto unknown processes to the global cycles of carbon,
nitrogen, sulfur, and phosphorus. Still, the basic principle of the unity in biochemistry holds true. In this chapter, I present a personal selection of newly discovered
ways used by prokaryotes to obtain energy and carbon for growth, all exciting new
microbial “acts” that can be added to Kluyver’s microbial “variety show.”
162
A. Oren