MUSEOS DE LA SEDA / SILK MUSEUMS

2.3) Other new uses of silkworm in Biotechnology In addition to the applications exposed previously, there are many others that contribute to create a substantial economic and scientific value through the rearing of silkworm. The first one, is the use of silkworm as a bio factory for the production of recombinant proteins and vaccines. Usually, high value proteins widely used in biotechnological industry are produced in protein expression platforms, such as genetically modified bacteria, yeast, plants and a variety of cell cultures. In the 1990s, Japanese researchers reported that silkworm larvae could be used as a protein expression platform. The technology is based in the construction of expression vectors based on genetically modified baculoviruses, a group of specific insect viruses. These vectors are modified with the deletion of one of their genes and the insertion instead of a foreign gene that codifies the expression of the protein of interest. When the larva or the pupa of the silkworm is injected with this modified virus, it proliferates and express the new protein, which accumulates in the body of the insect. After a period of five days, the protein can be extracted and purified from the insect. Given the high value of the proteins obtained (cellular growth factors, cytokines, antibodies, vaccines) this process is profitable and scalable and is the model business of several biotechnological companies in Japan and China. Apart from this, silkworm has many other uses. It can be used as an animal model for eval- uation of drugs for therapy of diabetes or detection of toxic reagents, and also as an animal model for high resolution genomic studies. Recently, in the context of the new uses of insects as a source of food, silkworms may have an important potential. Its body accumulates valu- able bioactive polyphenols contained in the mulberry leaves that are their only feed and that have been documented as a therapy for diabetes and metabolic disorders. So, the lyophilised powder obtained from silkworm larvae could be used as a functional food additive in the field of nutraceuticals. From the previous exposition, it is easy to deduce that this package of new technologies and applications associated to silkworm has a very substantial economic potential. This fact has been noticed by the biotechnological and biomedical industry and it has produced a surge of spin-off companies with a business model focused on marketing of bio products of silkworm and silk derivatives. At present, there are at least five international companies that profit from the above described technologies, and in Spain, we can mention one spin- off company of the Department of Science of Materials of the Polytechnic University of Madrid devoted to the development of silk technologies. As a consequence, we can think of a resurgence of sericulture in Europe, which in contrast with the old textile-oriented sericulture, is based on biomedical technology and advanced materials. It is clear that the socioeconomic landscape of this “new silk” is very different from the one focused on the production of textile fibre. The new approach will require a small amount of highly purified and processed silk produced by a few highly skilled workers, obtained in white rooms, and having an exceptional added value. These developments open the way for a renaissance and continuity of sericulture in the Western, where textile silk was not profitable anymore, but where there is a competitive science in the fields of biotechnology and biomedicine. Interest- ingly, they constitute a case of study for the fascinating story of this beautiful organic materi- al, documented 8500 years ago, still very relevant as textile fibre and that suddenly mutates in one of the most advanced materials at the cutting edge of biomedical technologies. 64