Worldchanging: Plentiful Freshwater from Hybrid Bio-synthetic Membranes

The need for plentiful freshwater is one of this planets greatest environmental needs. While the ocean covers more of Earth's surface than the continents, ocean water is undrinkable and unusable for crop irrigation. Until now, it has been prohibitively expensive to desalinate salt water for human use. Until now:

The experimental membranes, currently in the form of vesicles, show significantly higher water transport than existing reverse-osmosis membranes used in water purification and desalination. The researchers describe their membranes in a paper accepted for publication in the Proceedings of the National Academy of Sciences. The paper is to be published in PNAS Online Early Edition this week. ... To make their protein-polymer membranes, the researchers begin with a polymer that self-assembles into hollow spheres called vesicles. While the polymer is assembling, the researchers add Aquaporin Z – a protein found in Escherichia coli bacteria.

...“By varying the amount of Aquaporin Z, we can vary the membrane’s permeability,” Kumar said, “which could be very useful for drug-delivery applications.”

With their high permeability and high selectivity, the biomimetic membranes also are ideal for water treatment by desalination, which is becoming increasingly important for water purification in semiarid coastal regions.

When tested, the productivity of the Aquaporin Z-incorporated polymer membranes was more than 10 times greater than other salt-rejecting polymeric membranes.

Physorg

E. Coli bacteria can be modified to mass-produce large numbers of the aquaporin protein efficiently and economically, in the same way that E. Coli is used to mass produce various pharmaceuticals. A hybrid biological-synthetic membrane of this type is a crude example of the "grobyC" concept--inserting biological materials into mechanical or synthetic substrates and devices.
These bio-synthetic membranes can also be used to purify other types of tainted water besides saltwater and brine water. Studying the use of this type of membrane in waste treatment/water purification should be a top priority of persons who consider themselves environmentalists.