“Synthesis, purification and analysis of a new plant biopolymer”

The impact of non-biodegradable plastics on the biosphere is one of the great problems that humankind has to face in recent years. Transgenic photosynthetic organisms, like plants or algae, may be an alternative and sustainable way to produce commercially valuable compounds, such as biodegradable polymers, as long as high recombinant compound accumulation is guaranteed. The idea developed in this work was to use an engineered version of the storage protein (phaseolin) of Phaseolus vulgaris, in which a cysteine residue has been added to its C-terminal region. As previously demonstrated, when the modified phaseolin gene was expressed in the nucleus of tobacco plants, the phaseolin polypeptides were able to form dimers. Here it is shown that phaseolin, codified by a gene inserted in the chloroplast DNA, originated polymers linked by disulfide bridges and localized in the thylakoid fractionThe same gene, after codon usage optimization, was also used for the transformation of unicellular algae, from which polymer purification may be simpler than in plants. Preliminary results suggest that these polymers could be useful in biomedical field, for example as a matrix on which to load drugs for a controlled release or as a material for the construction of biocompatible gauzes