In May 2015 Ph. D. student Wei-San Chen was awarded two prestigious prizes for his research. One grant was awarded by the Ministry of Education of the Taiwanese government, the other by the Taiwanese company Delta Electronics Foundations. The awards include personal grants of € 12.000 each and are granted to outstanding environmental Ph.D. and M.Sc. students, who are studying abroad. Chen received the prizes for his innovative studies aimed at minimizing the environmental impact of organic waste treatment: reduce use of energy, the release of greenhouse gasses and pollution.
Organic waste can be anaerobically digested into volatile fatty acids (VFA’s, for example acetate), CO2 and hydrogen. By adding ethanol, microorganisms convert these VFA’s into caproic acid, a valuable component that can be used to synthesize many products, including biofuels. Chen looked into this process of caproic acid synthesis from a different angle: he analyzed the environmental impact of the method by using life cycle assessment (LCA’s) for every step in the process. ‘Based on these LCA’s, I modified the process into a more environmental friendly procedure’, Chen explains.
Chen’s research indicated that replacing ethanol in the caproic acid formation procedure would result in a more environmental friendly process. ‘Ethanol has a relatively high environmental impact: it is made from sugars that come from crops grown with fertilizers´ Chen explains. ‘In addition, ethanol production may lead to eutrophication and acidification of the environment.´ The scientist investigated the use of methanol to replace ethanol. Methanol can be derived by lignocellulose, a compound abundantly present in agricultural and municipal waste. So, no sugar is needed for its formation. Although the current efficiency of conversion was still low, methanol could successfully replace ethanol to biologically synthesize caproic acid (fig. 1). Chen: ´In the modified method all components are now derived from organic waste, making it potentially more sustainable.´
Technology of nature
Chen is now focusing on in-creasing the efficiency of the new process. ‘Current caproic acid production with organic waste and methanol is about 10 times lower than the traditional method’, he says. ‘However, this is only the proof-of-principle; we will perform long-term operation to find out the most comfortable working condition for these microbial workers in order to ele-vate the production and have an efficient, sustainable and economic viable process ‘. In addition, the scientist focuses his work on environmental friendly separation techniques to extract caproic acid. Efficiency is crucial here, but in this research, LCA´s are the starting point to guarantee an environmental friendly process. Chen: ‘Applying the technology of nature is the spirit of all my research'.