Tree of life
Gene-altered rubber plants are putting human
proteins on tap
Human proteins have been produced for the first time in
genetically modified rubber plants.
The breakthrough offers potential for the cheap harvesting of
many therapeutic and industrial proteins from rubber
plantations. It was announced on Friday at the "BioVision"
conference on biotechnology in Lyon, France.
"It's a living bioreactor, and we're getting continuous
production simply by tapping it for milk," says Hoong-Yeet
Yeang of the Rubber Research Institute of Malaysia in Kuala
A gene in Yeang's rubber trees produces human serum albumin,
a vital nutrient given to patients on drip feeds in intensive
Yeang could not give a precise yield. But he says that the
trees produce milligrams of the protein per millilitre of latex,
the milky sap from which rubber is made.
"Trees produce between 100 and 300 millilitres per tree per
tapping, and you can tap every two days, or even daily," he
says. With 400 trees per hectare, the harvests could be
substantial and extremely cheap, he says.
He thinks that yields can be raised substantially higher thanks
to recent breakthroughs in genetic technology. His team has
isolated the gene switches, called promoters, from rubber
plants that turn genes on exclusively in the latex.
So far the experiments have relied on gene switches from
viruses, which are less efficient. "By driving production in latex
itself, yield could be significantly improved," he said.
Yeang says that such copious yields make it economical to
produce industrial proteins as well as valuable
pharmaceuticals. "Because rubber trees are so cheap, it can
be used to make proteins of moderate value, such as those in
shampoos or toothpaste, or enzymes for detergents," he said.
And after extracting proteins of value, the rubber could still be
sold. So tyres on aircraft could end up being made from the
by-products of protein production.
Yeang also claimed he has produced antibodies against
bacteria in the sap. He says these would be used in a personal
care product, such as toothpaste. But he would not give any
further details due to the constraints of commercial