At the American Chemical Society Conference, Dr Malcolm J Brown Jr, a leading researcher on nanocellulose since the 1970s, has reported major advances in producing nanocellulose from blue-green algae.
The great strength and light weight of nanocellulose have fostered interest in using it in everything from lightweight armour and ballistic glass to wound dressings and scaffolds for growing replacement organs for transplantation.
Cellulose is the most abundant organic polymer on earth but most of it is in the form of wood fibre and plant cell walls. Very few organisms produce cellulose in its nanostructure form.
Nanocellulose research has a long history. As early as 1868, Louis Pasteur noted that vinegar-making bacteria produce the “sort of moist skin” now known to be nanocellulose.
Nanocellulose exists in two forms, long-chain polymers and crystals. In the 1980s and 1990s, Dr Brown’s team sequenced the nanocellulose genes from A. xylinum bacteria and identified the genes involved in both polymerizing and in crystallizing it. However, they recognised that bacteria would not be suitable for making commercial amounts of nanocellulose because they would need a high-purity broth of food and other nutrients to grow.
Dr Brown has now reported that his team has genetically engineered cyanobacteria (blue-green algae) to produce the long-chain form of nanocellulose and are progressing towards producing the crystalline form, as well as scaling up from laboratory-sized tests to larger outdoor facilities.
The advantage of using cyanobacteria is that they make their own nutrients from sunlight and water – and remove carbon dioxide from the atmosphere while doing so. Cyanobacteria also release nanocellulose into their surroundings, making it easy to harvest.
Dr Brown describes the process as “one of the most important potential agricultural transformations ever”,