A biological adsorption system to remove pollutants or toxins from water

In many parts of the world, water is contaminated with persistent organic pollutants, such as polychlorinated biphenyl (PCB) and organochlorine (OC) residues, and toxic metals, such as mercury and lead. It is difficult and expensive to clean these pollutants, especially when the concentrations are relatively low. They are problematic, due to their persistence in the environment and potential toxic effects on ecosystems and humans. Concerns related to these contaminants are particularly pertinent in Asia where the use of pesticides and metal emissions have been increasing dramatically due to changing agricultural practices and rapidly expanding industrialization.

In addition, there are many industrial contaminants that need to be cleaned up. As the global environment becomes more polluted, there are urgent needs for various novel technologies to deal with various contaminants to meet the needs of industry, governmental agencies, and consumers.

Bacterial Cell Surface Display Technology

The technology is based a method whereby AopB-related proteins are used as carriers to display passenger proteins on the surface of bacteria. The AopB-related proteins covered under the patent are derived from Agrobacterium outer membrane protein AopB and from Rhizobium RopB, as well as the corresponding variants, homologs and fragments.

The displaying host bacteria may be Agrobacterium and Rhizobium, both of which are non-pathogenic and harmless. Agrobacterium and Rhizobium can survive well in the environment, including water. Thus, the technology has a natural advantage in dealing with environmental problems.

This bacterial surface display system can distinguish the technology from any existing technologies as follows.

• It can directly display complex proteins with quaternary structure and disulfide bonds
• Displayed peptides can be at least 450 amino acids long
• The display can be regulated by an acidic pH
• Displaying host bacteria can survive well in the environment.

The unique features of this technology can enable the practitioners to gain the following advantages in the environmental sector:

• Our system can display complex proteins with quaternary structure and disulfide bonds; displayed peptides can be at least 450 amino acids long. This may allow us to develop better toxin-absorbers and catalysts.
• The display can be regulated by an acidic pH. This may facilitate better control and industrialization of the process.
• The “displaying” gene and its homologs are present in soil-borne Gram-negative bacteria like Agrobacterium and Rhizobium, which are harmless to humans (or mammals) and therefore should be of no public safety concerns.
• The displaying bacteria (Agrobacterium and Rhizobium) can survive well in the environment. This will allow the practitioners to develop products that can be released into the environment.

This bacterial cell surface display technology is useful for developing novel adsorption systems, because of the following.

• The technology can be used to display proteins or peptides of high affinity activities for persistent organic pollutants and toxic metals.Display of these affinity molecules on the bacterial surface can facilitate direct trapping, since they can bind the toxins on the surface.
• Bacteria are large and thus industrial removal of toxins trapped on bacterial surface can be simplified. Bacteria are also easy to be manipulated and inexpensive to be manufactured and distributed.
• Display of the affinity molecules on the bacterial surface can facilitate the selection of higher affinity molecules by using the high-powered cell sorting technology, such as fluorescence-activated cell sorting (FACS).
• The technology is expandable. Once the practitioners have developed an adsorption system to remove pollutants or toxins, they can use the technology to develop systems that can remove other pollutants and toxins.

This patented technology can be used to develop proprietary capabilities to treat polluted and industrial water. It is also of strategic importance as water treatment capability is critical.

The capabilities can be expanded to treat other pollutants and toxins.Therefore, the practitioners can develop the proprietary capabilities to treat important pollutants and toxins.

The adsorption systems developed based on this technology can be developed as consumer products that can be used at homes and offices. The adsorption systems can be used as water treatment facilities at industrial levels.

Toxin/metal ion binding proteins have not yet been displayed on bacterial cell surface. The work is ongoing. However, many other model proteins have been displayed for proof-of-concept

Proof-of-concept stage reached with respect to successfully displaying various proteins and enzymes on bacterial cell surface. Examples include: (Example: GFP, large dimeric enzyme PhoA, SARS spike (S) protein, te ZZ domain, the anthrax toxin component - protective antigen (PA) and ZZ-PA fusion protiens.

Exclusive/non-exclusive Licensing; collaboration/partnership for further development in specific applications