BIOREMEDIATION OF HEAVY METALS USING GENETICALLY MODIFIED Chlamydomonas reinhardtii

BUCHENSKY, CELESTE; PAGANI, MARIA AYELEN; BURDISSO, MARÍA LUCÍA; GOMEZ-CASATI, DIEGO FABIAN; BUSI, MARIA VICTORIA

Parana

Congreso; LIV Reunion Anual de la Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular; 2018

Heavy metals are an important source of water pollution around the world. They are toxic at very low concentrations and cannot be degraded or destroyed. Cells have diverse strategies for handling of heavy metals: all eukaryotic organisms synthesize small proteins called metallothioneins, which are the first response to high concentrations of metals. In addition, most organisms present frataxin, an essential protein involved in iron homeostasis and related to other metals too, such as copper. In this work we propose C. reinhardtii as a model for remediation of heavy metals in water and effluents. This unicellular green algae, that has a simple life cycle, allows us to isolate transgenic cells easily. Transgenic Chlamydomonas expressing a soybean metallothionein (GmMT3) or frataxins of C. reinhardtii (CrFH) and maize (ZmFH2) were obtained by electroporation and the presence of transcripts was confirmed using quantitative Real Time PCR. In liquid cultures supplemented with Cu, the GmMT3 lines and those that express frataxins grow faster than the wild type line. ICP-MS analysis of the recovered cells showed that transgenic lines have a higher capacity than the control line to incorporate metals such as Cu, Fe and Zn, both in their cell wall and intracellularly. Currently a practical application over a metallic sludge is being tested. Results are promising since transgenic lines resist better the stress generated by high amounts of heavy metals, developing larger amounts of biomass (with the ability to adsorb and absorb metals) in a shorter time than the wild type strain.