Harnessing Bacterial Power

While coal-fired power plants are seen as a major cause of environmental pollution and nuclear power considered risky because of potential radiation leakage, humans are searching for alternative and renewable energy sources like solar and wind power. A genetic engineering team formed by undergraduate students of science and engineering at CUHK has devised a new way of generating electricity with solar energy and bacteria.

Halorhodopsin is a light-driven ion pump that can be found in halobacteria. When activated by light, halorhodopsin transports surrounding chloride ions into cells of the bacteria. The CUHK team makes use of this characteristic of halorhodopsin to make BioBrick parts that can alter chloride ion concentration by light. In synthetic biology, BioBrick parts are standard biological parts similar to electronic components or Lego bricks.

The BioBrick parts developed by the CUHK team have two potential applications. They can be used to make a 'mixing-entropy battery' that takes advantage of the salinity difference between seawater and freshwater to produce electricity. They can be also used to desalinate seawater to make drinkable water by controlling halorhodopsin with light to absorb chloride ions of seawater into bacteria. Their ideas, if realized, can help address two pressing environmental issues: water and energy.

The team comprises four professors, three student instructors, and 24 undergraduate students, including 19 life sciences students, four engineering students and one chemistry student. These young researchers believe in Einstein's words: 'Imagination is more important than knowledge.' Their imagination has opened up undreamed-of possibilities for halorhodopsin. Their creative project won a gold medal at the iGEM (International Genetic Engineered Machine) Asia Regional Jamboree in October 2011. They also won the Best BioBrick Measurement Approach and the Best New BioBrick Part (Natural) awards.

Gordon Chan, a biochemistry student, said, 'iGEM offers us a rare opportunity to use some state-of-the-art technological instruments and polish skills that are beyond the formal curriculum, including experimental techniques, writing skills, leadership skills, social skills, statistical analysis and presentation skills. The heavy workload also trained up my perseverance.'

The students' work was greatly acclaimed by the panel of judges. One of the judges, Prof. Mukund Thattai of the National Centre for Biological Sciences (India), who presented the team with the Best BioBrick Measurement Approach award, commented that the team had done extensive characterizations to the BioBrick which is well ready for use by the research community. Another panel judge, Prof. Qi Ouyang of Peking University, who presented the team with the Best New BioBrick Part (Natural) award, commended the team's creativity in making use of an ion transporter found in bacteria to generate electricity.

Established by the Massachusetts Institute of Technology in 2004, iGEM is an annual premier synthetic biology competition for undergraduates worldwide.

CUHK iGEM team website: http://2011.igem.org/Team:Hong_Kong-CUHK