Rensselaer Alumni Magazine - Fall 2017 - 12
CHEMICAL AND BIOLOGICAL ENGINEERING
Bacteria Make Natural Pigment
From Simple Sugar
Augustine sAckett, A student At RensselAeR in the
1850s, was inducted into the National Inventors Hall of Fame at a ceremony May 4 at the
National Building Museum in Washington, D.C.
Sackett was recognized
for the disruptive invention of drywall, made of
paper and gypsum,
"Few modern products
have transformed construction as much as drywall," reads his Hall of
Fame citation. "Sackett Board, the prototype for
drywall, was patented by Augustine Sackett in
1894, and the evolution of Sackett's invention
shaved weeks off the time needed to finish a
building. Today, the average new house
in America contains over 6,000 feet of drywall.
It is a staple of modern structures."
Augustine Sackett (1841-1914) studied at
Rensselaer in 1857-58, and was listed as a
member of the Class of 1862. His studies at
Rensselaer were interrupted by the Civil War,
during which he served as an assistant engineer
in the Union Navy. After the war he settled in
New York City, where he worked as an inventor
Prior to 1894, Sackett's invention of a product intended as a sheath for walls and ceilings
led to the formulation of Sackett Board.
"Consisting of a core panel of gypsum
plaster sandwiched between two thick sheets
of paper, Sackett Board was rigid but soft
enough to admit nails, and tough enough not
to crack during installation or ordinary use,"
continues his citation. "It replaced the timeconsuming and labor-intensive method of wetplaster wall construction. Sackett Board could
be installed in a single day."
Sackett invented gypsum wallboard and
the specialized machinery to make it, and his
company built several plants for its production.
In 1909 the U.S. Gypsum Company purchased
the Sackett Plaster Board Company.
12 reNsselaer/Fall 2017
Nature makes the vibraNt pigmeNts
manufacturers want for foods and cosmetics, but getting them from plants to the
products we buy is so difficult that many
manufacturers rely on artificial colors.
Now, researchers at Rensselaer have
shown that four strains of E. coli bacteria
working together can convert sugar into
the natural red anthocyanin pigment
found in strawberries, opening the door
to economical natural colors for industrial
The research marks the first biosynthesis method using four strains of bacteria to
manufacture a compound
in a single step, says
Mattheos Koffas, professor
of chemical and biological
engineering. Results appear
in mBio, a publication
of the American Society
"For the first time, we
are able to completely
in a biological system,"
says Koffas. "We feed the
bacteria glucose and they
do the rest. This demonstrates that an inexpensive
technology can produce
these valuable compounds."
Manufacturers are increasingly interested in natural colors, a shift founded in
research documenting the health hazards
Researchers at Rensselaer have shown that
four strains of E. coli bacteria working together
can convert sugar into the natural red anthocyanin pigment found in strawberries, opening
the door to economical natural colors.
of artificial colors for foods and cosmetics.
Natural pigments found in plants such as
anthocyanins, carotenoids, or lycopene
produce indisputably safe colors. Anthocyanins exist in a far broader spectrum
than other pigment classes-producing
all colors except green-and are responsible for natural color found in foods like
blueberries, raspberries, black rice, and
the hues of autumn leaves.
But producing anthocyanins for industrial use is challenging: plant-derived
pigments require costly processing and
produce inconsistent results; and because
anthocyanin molecules are complex,
chemists have been unable to synthesize
Koffas' lab has been investigating a
production method of anthocyanins
involving genetic engineering since 2005.
The current research divides the entire
pathway among four different strains of
bacteria, modified to assemble anthocyanin in stages. Researchers divided the
pathway into "modules" that produced
intermediates that easily diffuse out of
the bacterial cell. When combined in a
single flask, the first bacteria ingest sugar
and produce "intermediate" compounds,
phenylpropanoic acids, which are ingested
by the second bacteria, which produces
a second intermediate, and so forth until
the fourth strain produces anthocyanin.
"I have no doubt that production of
anthocyanins from a recombinant microbial host is the only viable method for
making these compounds in an economically sustainable manner," says Koffas.
NATIONAL INVENTORS HALL OF FAME