Bacteria are able to perform computational tasks since they possess a huge
metabolic repertoire that can be controlled by activating or disabling
their genetic code. Much recent interest has been generated by the
computational powers of bacterial systems through the endeavours of J
Craig Venter following the Shotgun II expedition where he trawled the
Sargasso Sea for new bacterial species effectively doubling the number of
known species overnight. Venter then set to work on shotgun sequencing
these new species to try to identify interesting genes that could be used
computationally to produce useful materials. Bacterial computing provides
an important mechanism for the future of chemical manufacturing processes
as they are very cheap to produce and can be grown on a large scale to
manufacture valuable substances such as, smart drugs where modified
bacteria identify tumour sites and synthesize killer proteins directed at
the cancer, certain kinds of plastics and new materials such as the
bacterial cellulose that is harvested by the Scottish company Cellucomp to
make durable yet light weight bicycle frames and fishing rods. Bacterial
computing is cost effective from a manufacturing perspective as it does
not require the expensive sterility nor the precision needed for the
production of computer chips and despite the variations in their
composition, bacterial computers can still produce a reliable outcome. The
computing power of a bacterium is small compared to silicon transistors
and the speed at which bacteria can process information is unclear, though
even a billion bacteria are unable to match the speed of a Pentium
processor. Bacteria can be produced cheaply in vast numbers which greatly
outweighs the sluggishness of their metabolic calculations and are able to
respond to changing production demands or climate.
Additionally, bacteria have other computationally exploitable properties
besides their pliable genomes. For example, the quorum-sensing bacteria
possess powerful intercellular signalling systems that produce and release
chemical signal molecules that act as communication circuits. These
chemicals allow quorum-sensing bacteria to coordinate their gene
expression through which the behaviour of the entire community can be
controlled and scientists are able to programme whole populations of
bacteria to behave in a certain way that favours the action of a
particular antibiotic by creating synthetic versions of these signalling
molecules. Also the properties of certain extremophile bacteria that are
able to live in hostile conditions not normally compatible with life, are
being harnessed to create new materials such as the bio concrete being
developed at the University of Delft where bacteria are being engineered
to repair cracks in concrete .
The Dune project presented by Magnus Larsson at the recent TEDGlobal
conference in Oxford is Magnus Larsson's winning competition entry for the
2008 Holcim Foundation's Awards for Sustainable Construction held in
Marrakech, Morocco. This ambitious architecture explored the large scale
deployment of bacteria to combat the progressive desertification of
Nigeria by growing a 6,000km wall using the bacterium, bacillus pasteurii,
which rapidly binds sand into firm sandstone structures. Larsson's
significant re-imagining of architectural construction methods using a
bottom-up approach to a longstanding problem depicts how the practice of
the built environment may approach sustainable practices in new ways.
"A vast 3D printer made of bacteria crawls undetectably through the
deserts of the world, printing new landscapes into existence over the
course of 10,000 years…"
http://bldgblog.blogspot.com/2009/04/sandstone.html [Accessed May 2009]
Bacterial computing is still in its earliest stages of development but
Venter's group is rapidly advancing what is already possible. Venter
recently announced the results of his lab's work on genome transplantation
methods at the start of 2008 when he announced the creation of a synthetic
genome using a modified organism and is the largest man-made DNA structure
by synthesizing and assembling the 582,970 base pair genome of a
bacterium, Mycoplasma genitalium JCVI-1.0, dubbed Mycoplasma laboratorium
www.jcvi.org/cms/press/press-releases/browse/5/ [Accessed December 13
2008. The artificial sequence awaits activation by inserting it into a
hollowed out shell of a donor species to 'kick start' reproduction, a
procedure which is also a significant technical challenge though this
significant advents heralds the advent of designer-made chemical computers
that are able to synthesize large amounts of expensive materials that are
difficult to acquire through other manufacturing processes.
Venter recently commented that "Now we know we can boot up a chromosome
system. It doesn't matter if the DNA is chemically made in a cell or made
in a test tube. Until this development, if you made a synthetic chromosome
you had the question of what do you do with it. Replacing the chromosome
with existing cells, if it works, seems the most effective to way to
replace one already in an existing cell systems. We didn't know if it
would work or not. Now we do."
The organism has already sparked controversy since the Venter Institute
filed for patents in the U.S. and internationally, which has been met with
heated opposition from the Action Group on Erosion, Technology and
Concentration [ETC] watchdog group.
"The idea of own¬ing a spe¬cies breaches "a so¬ci¬e¬tal bound¬ary," said
Pat Mooney of the Ot¬ta¬wa, Canada-based ETC Group, which is asking the
pat¬ent ap¬pli¬cants to drop their claim. Creat¬ing and own¬ing an
or¬gan¬ism, he added, means that "for the first time, God has
com¬pe¬ti-tionhttp://www.world-science.net/othernews/070607_mycoplasma.htm
Venter's synthetic organism has huge implications not just for the
practical aspects of biological design or how species are defined but is
also raising fundamental questions about how, or whether, biological
organisms should be used as material computers.
Venter notes that "We're coming up with new modified life forms, and we
should be able to go from the digital world right to the analogue world in
the computer, and we have a team working on a program to do that,
designing a species in the computer. It's only a short time away from
doing that just to have systems crank out synthetic chromosomes. In fact
I've talked to various funders about trying to design a robot that could
build a million chromosomes a day. Because then we can have a new field
that I call combinatorial genomics."
In a recent Silicon Valley meeting held by John Brockman's organization
'The Edge', Venter and colleague George Church noted that the rate at
which gene technology is now improving, puts silicon to shame. Observing
that Moore's Law (the exponential advancement of technology) applied to
gene technology they suggested that the world would be changed by the
ability to routinely read genetic sequences into computing systems and
then store, replicate, alter and insert them back into living cells.
This is an exciting time for the future of architectural practice. Every
surface of the built environment is already teaming with bacteria that
have the potential to perform biochemically and even aesthetically useful
functions. It does not take a great leap of imagination to envisage how
much more active and useful the surfaces of our buildings could become if
they benefited from the full range of metabolic exchanges present in the
bacterial repertoire. Design of architecture at the cellular scale where
buildings are not viewed as sterile & inert object by the selection and
cultivation of naturally occurring bacteria such as, those that glow in
the dark or can metabolize pollutants and toxins on the surfaces of our
buildings, could provide a possible way of improving the health of our
cities, if done in a careful and considered way.
It is likely that the first architectures exploring the possibilities of
bacterial computation will explore the potentially symbiotic relationship
between naturally occurring (wild type) organisms with traditional
architectural materials. For example, bacterial films (that are
extraordinarily good at edge-mapping under in response to light) could be
applied as motifs to act as a sundial on the façade of an architecture
that could be made of sandstone, which can hold large quantities of water,
can act as rigid support for the bacterial film and supply the bacteria
with nutrients in solution so that they can perform their computational
functions.
Symbiotically designed materials will influence architectural practice
beyond the realm of the traditional building and extends into all aspects
of our environment and landscape. Interventions may be thought of as
synthetic ecologies where it is acknowledged that unlike the expectations
of twentieth century technologies, there is no one solution (bacterial
monoculture) that fits all ecological niches. Architects will need to
become familiar with ecological networks and principles of biological
'succession', where bacteria may even be strategically placed to be
replaced by more complex organisms anticipating the change in metabolic
function of the Living Architecture over time.

 Synthetic ecologies generated by bacterial culture and other metabolic
materials may play a role in developing Life Cycles for Living
Architecture. Condemned buildings may be dissolved, or digested into
recyclable materials by metabolic materials that feed on the derelict
buildings and are left to decay for a number of weeks before the products
are recycled. Toxic dust and nanoparticles, such as asbestos, could also
be filtered from old buildings and not dispersed into the air as a
consequence of the demolition process. When the metabolic materials
themselves were no longer active they would senesce and decay back into
their components for recycling. Decomposed sites could be left temporarily
fallow of architecture to increase natural sunlight, promote new natural
and synthetic ecologies to become established and allow the public to
enjoy and engage with these new urban spaces. Communities would begin to
think of metabolic materials as being an intrinsic part of the urban
landscapes in the same way that we think of parks and gardens as being
connected to nature rather than being the outcomes of human intervention.

  
The images are of Magnus Larsson's Dune project and bacteriologist Simon
Park's photograph of silicon particle (sand) fixing bacteria entitled 'The
Moist Network)