Modified microalgae converts sunlight into valuable medicine


       A special type of microalgae can soon produce valuable chemicals such as cancer treatment drugs and much more just by harnessing energy from the sun. The team of scientists from Copenhagen Plant Science Centre at University of Copenhagen has published an article about the discovery in the scientific journal Metabolic Engineering.

       Researchers have succeeded in manipulating a strain of microalgae to form complex molecules to an unprecedented extent. This may pave the way for an efficient, inexpensive and environmentally friendly method of producing a variety of chemicals, such as pharmaceutical compounds.

       Post Doc Agnieszka Janina Zygadlo Nielsen, who along with colleagues Post Doc Thiyagarajan Gnanasekaran and PhD student Artur Jacek Wlodarczyk the main researchers behind the study said that their idea is to hijack a portion of the energy produced by the microalgae from their photosynthetic systems. By redirecting the energy produced to a genetically modified part of the cell capable of producing various complex chemical materials and induce the light driven biosynthesis of these compounds.


       The researchers have as such modified microalgae genetically to become small chemical factories with a build in power supply. According to the research team's study, this basically allows sunlight being transformed into everything ranging from chemotherapy or bioplastics to valuable flavor and fragrance compounds.


       Agnieszka Janina Zygadlo Nielsen described that the problem with many of these substances is that they are extremely expensive and difficult to make, and therefore produced only in small quantities in the medicinal plants.


       “When a solar concentrator is used, the intensity of visible light is more and this plays an important role in the degradation process,” says Jai Prakash Chaudhary, the first author of the paper from CSMCRI.


       "A cancer drug like Taxol for instance is made from old yew trees, which naturally produce the substance in their bark. It is a cumbersome process which results in expensive treatments. If we let the microalgae run the production this problem could be obsolete," she explains.


       Thiyagarajan Gnanasekaran clarifies that the method can be run sustainably and continuously, and this is what that makes it even more spectacular compared to present methods. "Our study shows that it is possible to optimize the enzymatic processes in the cells using only sunlight, water and CO2 by growing them in transparent plastic bags in a greenhouse. Theoretically, the water could be replaced with sewage water, which could make the process run on entirely renewable energy and nutrient sources. Recycling wastewater from industry and cities to produce valuable substances would surely be positive," he points out.



The microalgae cultures are able to grow rapidly using waste water and light.

Image credit: Department of Plant and Environmental Sciences, University of Copenhagen.


       Agnieszka Janina Zygadlo Nielsen added that if they can create a closed system that can produce the valued chemicals from water, sunlight and CO2, it would be a fully competitive method compared to the ones used today, where it is primarily extracted from plants or yeast and E. coli bacteria producing the substances. In theory it should be cheaper on the long run to use their method than adding the large quantities of sugar that the conventional yeast and E.coli cultures amongst other things need to function.


       However, the research team emphasizes that the method using genetically modified microalgae has its limitations at present time. As Thiyagarajan Gnanasekaran points out, the microalgae use much of the harnessed sunlight to keep their own metabolic processes running. According to the team the expanding methods and genetic tools for microalgae are likely to overcome these limitations in the near future.


ENVIS CENTRE Newsletter Vol.14, Issue 3, Jul - Sep, 2016
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