A Taiwanese research team has reported a breakthrough in carbon dioxide (CO2) capture biotechnology which it hopes will contribute to the reduction of greenhouse gas emissions in an efficient and environmentally friendly way.
The research team, led by Chang Chuan-hsiung (張傳雄), an associate professor at National Yang Ming University’s Center for Systems and Synthetic Biology, said the new process developed by the team enhances the ability of microalgae to capture carbon dioxide by up to 50 percent.
“We’ve set the goal of doubling the efficiency of the CO2 capture by the end of this year and tripling it next year,” Chang said.
As concern over global warming has risen, scientists have studied different ways of capturing carbon dioxide emitted into the air and storing it.
Chang said carbon capture technologies generally fall into three main categories: chemical and physical processes (which concentrate CO2 through combustion under high pressure and temperature) and biological processes.
The first two processes, Chang said, are costly, mostly due to their high consumption of energy and the large volume of chemicals they require, and produce severe storage and leakage challenges.
The process developed by the university, on the other hand, not only reduces carbon dioxide emissions, but turns the carbon fixed in the process into biomass (such as carbohydrates) through photosynthesis.
The biomass can then be converted into biofuel or other high-value materials.
“It is an eco-friendly biotechnology that does not harm the environment and can re-utilize the captured CO2 through natural processes like photosynthesis,” he said.
Chang said other research teams have studied biological methods to capture CO2, but have faced obstacles because of relying on traditional metabolic engineering approaches rather than his team’s genome engineering process.
“Our team is the first to achieve such a high rate of CO2 capture efficiency using a biological approach,” Chang said.
He said that microalgae only absorb the carbon dioxide they need to survive, but his team has been able to enhance their carbon capture ability by 50 percent through genome analysis, design and engineering.
That was made possible in 2008 when his team developed a genome analysis platform that enabled scientists to get a complete picture of how genes of microorganisms function and are regulated.
In the process developed by Chang and his team, microalgae grow in water that has a high concentration of dissolved CO2, which then is transported into microalgae cells through controlled gene regulation.
Through photosynthesis, the CO2 and water absorbed by the algae is transformed into carbohydrates, which can then be converted into valuable products, such as small molecule drugs, chemical compounds and biofuels.
“This way, we help reduce greenhouse gas emissions and turn them into renewable biofuels,” said Chang, who published the results of the study in the August issue of Energy & Environmental Science, a leading journal in the field of energy research.
The new biotechnology has been applied in the factory of Chung Hwa Pulp Corp in Hualien since early this year, with the company’s gas emissions collected and then diverted to photobioreactors, where the microalgae consume the carbon dioxide.
At present, the scale of the approach’s carbon dioxide capture is limited, with an initial target of between 3,000 tons and 10,000 tonnes per year, because the process is still in the developmental stage.