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Team:Hong Kong HKU/humanpractice/futureapps
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Revision as of 02:18, 28 September 2013
Future Applications
Revisit to Our Targeted Problem
Inorganic phosphate (Pi) is a widely used component for many different uses. In fact, complex phosphates are important ingredients of most of the commercial detergents. They include tri-sodium phosphate (TSP), tetra sodium pyrophosphate (TSPP), sodium tripolyphosphate (TPP), and hexametaphosphate (Calgon). On the other hand, by the Liebig's Law of the Minimum, the productivity of land areas is most likely determined by limitations on some nutritional elements. This implies that it is necessary to supply the nutrient elements for higher productivity of a crop under cultivation. As a result, phosphate is also added as a nutritional supplement in cultivation. However, due to the overuse of phosphate in industry, many of these phosphates are drained into rivers and lakes, causing eutrophication and pollutions in these waterways. Over the past century, 37 lakes in Europe and the U.S. were reported to become eutrophicated. Consequently, since eutrophication in waterways greatly promotes algal growth, algae bloom appeared more and more frequently over the past few years. Since then, scientists became more sophiscated in the search of new methods for sewage treatment to remove excess phosphate.
Creation, more than just Destruction
One old method to remove phosphate is by precipitation with metal salts (e.g. alum, lime, or iron). This method is expensive and may end up requiring further clean up of the toxic heavy metal by-products. Nowadays, environmental engineers adopt a more cost-effective method which removes Pi by converting them into polyphosphate (poly P) using genetically engineered bacteria. The engineers turn to a functional gene, ppk gene, which encodes an enzyme polyphosphate kinase (PPK) that catalyzes the formation of poly P from Pi. This enzyme works much faster and increases the extent of Pi removal from the medium. This method greatly improves the performance of Pi removal compared to the conventional method.
Our E. capsi is one of the systems which is capable of efficiently removing Pi from any medium (e.g. sewage). This can be used to prevent eutrophication of lakes and rivers. In our model, it is expected that membranes made up of our E. capsi can be put at every sewage outputs, even domestic ones, to reduce phosphate draining into nearby rivers and lakes. Moreover, if any algal bloom is about to happen, our E. capsi can be added to the local waterways to cease the rapid growth of algae and thus prevents devastating disruption to the local ecosystems.
Utilizing Poly-P
Regeneration of ATP
As an enzymatic phosphorylating agent in industry, ATP is considerably expensive since its raw materials are highly costly reagents (i.e. acetyl phosphate, phosphoenolpyruvate, and creatine phosphate) in the enzymatic ATP-regenerating systems. Fortunately, poly P seems to be a perfectly suitable substitute of these reagents as ATP can be regenerated using immobilized PPK on a column. Using this method, each industrial form of poly P costing $0.25/lb can provide ATP that equivalents to what would have fetched over $2000. This greatly reduces the cost of ATP-related industries and provides new ways for many enzymatic reactions.
Remediation of heavy metals
Heavy metals such as mercury, copper and even radioactive uranium are devastating to the environment if they are left freely in the environment. Thanks to the advance in biotechnology, biomining of these harmful metals is made possible using poly P. Genetically engineered bacteria are utilized to take up and sequester the heavy metals and thus removing them from the environment. For example, the popular P. aeruginosa which can withstand lethal doses of irradiation removes uranyl ions in a poly P-facilitated reaction. Overexpression of PPK1 aids the removal of uranium by precipitation of uranyl phosphate.
Antimicrobials
Poly P has long been widely used as a food additive, especially in the meat and dairy industry to enhance flavor, water binding, color retention, and emulsification, while preventing oxidative rancidity, since there is virtually no cost and no health concerns regarding the use of poly P in food. Poly P also inhibits growth of bacteria, especially in high concentration. High concentrations of poly P are bacteriocidal which cause cell lysis. While with sublethal concentrations, it may affect septum formation that leads to the formation of multinucleate and filamentous cells. This inhibitory effects can be attributed to its ability to chelate cations. In addition, poly P also causes membrane damage in Staphylococcus aureus, a common infectious bacteria, by triggering the leakage of Mg2+ from cells, leading to an unbalanced osmotic pressure, and thus membrane damage. Naturally antibiotic-resistant gram-negative bacteria Stenotrophomonas maltophilia and Acinetobacter ssp. through the disk diffusion technique, have shown that membrane permeabilizers like poly P increased susceptibility to a wide variety of antibiotics, including imipenem, ciprofloxacin, tetracycline, and rifampicin. All in all, these effects are found to be due to the metal-chelating properties of poly P.
It's all about E. Capsi
Last but not least, it is obvious that the potential development in poly P-related industry is absolutely undeniable. In modern world of 21st century, the monotonic approach towards economic growth is no longer acceptable in any body's eyes. A "dual" approach which balances environmental conservation and economic growth is certainly a more desirable way to adopt. In fact, this is the main idea and our vision on E. capsi and we are not just aiming at a small change inside the microcompartment. We are aiming at a big change in the world!
Revisit to Our Targeted Problem
Inorganic phosphate (Pi) is a widely used component for many different uses. In fact, complex phosphates are important ingredients of most of the commercial detergents. They include tri-sodium phosphate (TSP), tetra sodium pyrophosphate (TSPP), sodium tripolyphosphate (TPP), and hexametaphosphate (Calgon). On the other hand, by the Liebig's Law of the Minimum, the productivity of land areas is most likely determined by limitations on some nutritional elements. This implies that it is necessary to supply the nutrient elements for higher productivity of a crop under cultivation. As a result, phosphate is also added as a nutritional supplement in cultivation. However, due to the overuse of phosphate in industry, many of these phosphates are drained into rivers and lakes, causing eutrophication and pollutions in these waterways. Over the past century, 37 lakes in Europe and the U.S. were reported to become eutrophicated. Consequently, since eutrophication in waterways greatly promotes algal growth, algae bloom appeared more and more frequently over the past few years. Since then, scientists became more sophiscated in the search of new methods for sewage treatment to remove excess phosphate.
Creation, more than just Destruction
One old method to remove phosphate is by precipitation with metal salts (e.g. alum, lime, or iron). This method is expensive and may end up requiring further clean up of the toxic heavy metal by-products. Nowadays, environmental engineers adopt a more cost-effective method which removes Pi by converting them into polyphosphate (poly P) using genetically engineered bacteria. The engineers turn to a functional gene, ppk gene, which encodes an enzyme polyphosphate kinase (PPK) that catalyzes the formation of poly P from Pi. This enzyme works much faster and increases the extent of Pi removal from the medium. This method greatly improves the performance of Pi removal compared to the conventional method.
Our E. capsi is one of the systems which is capable of efficiently removing Pi from any medium (e.g. sewage). This can be used to prevent eutrophication of lakes and rivers. In our model, it is expected that membranes made up of our E. capsi can be put at every sewage outputs, even domestic ones, to reduce phosphate draining into nearby rivers and lakes. Moreover, if any algal bloom is about to happen, our E. capsi can be added to the local waterways to cease the rapid growth of algae and thus prevents devastating disruption to the local ecosystems.
Utilizing Poly-P
Regeneration of ATP
As an enzymatic phosphorylating agent in industry, ATP is considerably expensive since its raw materials are highly costly reagents (i.e. acetyl phosphate, phosphoenolpyruvate, and creatine phosphate) in the enzymatic ATP-regenerating systems. Fortunately, poly P seems to be a perfectly suitable substitute of these reagents as ATP can be regenerated using immobilized PPK on a column. Using this method, each industrial form of poly P costing $0.25/lb can provide ATP that equivalents to what would have fetched over $2000. This greatly reduces the cost of ATP-related industries and provides new ways for many enzymatic reactions.
Remediation of heavy metals
Heavy metals such as mercury, copper and even radioactive uranium are devastating to the environment if they are left freely in the environment. Thanks to the advance in biotechnology, biomining of these harmful metals is made possible using poly P. Genetically engineered bacteria are utilized to take up and sequester the heavy metals and thus removing them from the environment. For example, the popular P. aeruginosa which can withstand lethal doses of irradiation removes uranyl ions in a poly P-facilitated reaction. Overexpression of PPK1 aids the removal of uranium by precipitation of uranyl phosphate.
Antimicrobials
Poly P has long been widely used as a food additive, especially in the meat and dairy industry to enhance flavor, water binding, color retention, and emulsification, while preventing oxidative rancidity, since there is virtually no cost and no health concerns regarding the use of poly P in food. Poly P also inhibits growth of bacteria, especially in high concentration. High concentrations of poly P are bacteriocidal which cause cell lysis. While with sublethal concentrations, it may affect septum formation that leads to the formation of multinucleate and filamentous cells. This inhibitory effects can be attributed to its ability to chelate cations. In addition, poly P also causes membrane damage in Staphylococcus aureus, a common infectious bacteria, by triggering the leakage of Mg2+ from cells, leading to an unbalanced osmotic pressure, and thus membrane damage. Naturally antibiotic-resistant gram-negative bacteria Stenotrophomonas maltophilia and Acinetobacter ssp. through the disk diffusion technique, have shown that membrane permeabilizers like poly P increased susceptibility to a wide variety of antibiotics, including imipenem, ciprofloxacin, tetracycline, and rifampicin. All in all, these effects are found to be due to the metal-chelating properties of poly P.
It's all about E. Capsi
Last but not least, it is obvious that the potential development in poly P-related industry is absolutely undeniable. In modern world of 21st century, the monotonic approach towards economic growth is no longer acceptable in any body's eyes. A "dual" approach which balances environmental conservation and economic growth is certainly a more desirable way to adopt. In fact, this is the main idea and our vision on E. capsi and we are not just aiming at a small change inside the microcompartment. We are aiming at a big change in the world!
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