Plants as bioreactors

plant as bio reactor and its application

1. Plants as Bioreactors Shnaid Moosa

2. A Bioreactor is a device or vessels which are designed to obtain an effective environment for conversion of one material into some product by appropriate biochemical reactions Conversion is carried out by …… enzymes, microorganisms, cells of animals and plants, or sub cellular structures such as chloroplasts and mitochondria. Plants can be used as cheap chemical factories that require only water, minerals, sun light and carbon dioxide to produce thousands of chemical molecules with different structures. This process can either be aerobic or anaerobic

3. . There are different bioreactors and they have different applications are including those for cell growth, enzyme production, biocatalysis , food production, milk processing, tissue engineering, algae production, protein synthesis, and anaerobic digestion Bioreactors are classified depending on their operational conditions and the nature of the process . Bioreactors can be from different sources like animals, plants, microbes,etc

4. PLANTS AS BIOREACTORS Plant bioreactors refer to the use of transgenic plants and cell cultures of plants to make unlimited quantities of commercially important substances like recombinant proteins including antibodies and vaccines using biotechnology oriented techniques Using genetic engineering, cereal plants, fruits plants, legumes and vegetable plants have the capacity to become low cost bioreactors to make molecules that in the normal scheme of things would not have been available from plants. Human growth hormone was the first drug that was produced using plant bioreactors, in this case from the transgenic tobacco Most of the research has been directed towards using plant bioreactors • Therapeutic proteins • Edible vaccines • Antibodies for immunotherapy

5. There are two basic processes that are used to produce recombinant proteins in plants generating the transgenic plants by stable integration of transgene into plant genome transient expression of the transgene  using plant viruses as vectors The other techniques used for direct gene transfer are electroporation, polythene glycol mediated gene uptake and particle bombardment.

6. TYPES OF PLANT REACTORS There are different plant bioreactors classified based on where the protein is produced SEED-BASED PLANT BIOREACTORS PLANT SUSPENSION CULTURES HAIRY ROOT SYSTEM BIOREACTOR CHLOROPLAST BIOREACTOR

7. CHLOROPLAST BIOREACTOR The nuclear chromosomes of chloroplasts are inserted with the foreign genes that are responsible for required product. Insulin, interferons and other proteins can be prepared in chloroplast bioreactor An example is the high yield in the expression of human serum albumin protein in chloroplast

8. HAIRY ROOT SYSTEM BIOREACTOR This has rhizosecretion caused due to infection of agro bacterium rhizogenes and is highly stable and suitable for different biopharmaceuticals It offers extreme biosynthetic stability and is suitable for making biopharmaceuticals as for example scopolamine in Hyoscyamus muticus L. hairy root culture.

9. PLANT SUSPENSION CULTURES In this plant cells are grown under sterile conditions as suspension or callus cultures and given the appropriate hormonal supplements for growth  and are used in expression of recombinant proteins, secondary metabolites and antibodies . For example, is the expression of 80-kDa human lysosomal protein

10. SEED BASED PLANT BIOREACTORS Seed is the most suitable bioreactor because of their large protein accumulation during its development But specificity of expression and subcellular storage environment are the factors that will decide which seeds are used for producing desired products There are two types of seed based plant bioreactors Seed protein storage vacuole bioreactors Seed oil body bioreactors

11. Seed protein storage vacuole bioreactors The protein storage vacuoles in seeds contain some dominant sub compartments like matrix, globoid and crystalloids which are best for storing recombinant protein. Matrix is suitable for soluble storage proteins, globoids for hydrolytic enzymes and crystalloids for some intrinsic protein sequences. Seed oil body bioreactors This bioreactor can store a large amount of macromolecules. It has oleosin proteins which are ideal carriers of heterologous proteins encircling the seed oil body. This also provides recognition signal for lipase binding during oil mobilization in seedlings

12. An example is the successful expression of the human lysosomal enzyme alpha-L- iduronidase in Arabidopsis thaliana seeds The advantage of these systems is that, proteins do not degrade at ambient temperature and are stable for long term storage

13. Vaccine antigens Antigens like Insulin, rotavirus enterotoxin, anthrax lethal factor, HIV antigen, foot and mouth disease virus antigen, heat stable toxin have been produced in plants. Therapeutic products The first successful production of a functional antibody, namely a mouse immunoglobulin IgGI in plants, was reported in 1989. In 1992, C.J. Amtzen and co-workers expressed hepatitis B surface antigen in tobacco to produce immunologically active ingredients via genetic engineering of plants

14. Nutritional components β -carotene (Naqvi et al., 2009), Lycopene (Fraser et al., 2002), Flavonoid ( Butelli et al., 2008), Nutraceuticals (Kang et al., 2009), Fatty acid (Hoffmann et al., 2008), Vitamins ( Nunes et al., 2009), Minerals (Lee & An, 2009) & Carbohydrates (Regina et al., 2006).

15. Biodegradable plastics Polyhydroxyalkanoates : biodegradable polymers which occur naturally in plants. Plant was engineered to produce PHAs or PHBs in the various plant cell compartments Industrial products Most expensive Drug – Hgc hST (Human somatotropin) rHLF (Recombinant human lactoferrin ) Synthetic fiber : Produced from Potato and tobacco .

16. ADVANTAGES They are cost effective , faster than transgenic animals , can produce large biomass pathogens do not effect animals and humans . Easy storage for long time

17. DISADVANTAGES The difference in codons of prokaryotes and plants  can lead to inefficient expression different polysaccharides may be attached to proteins and some plants may contain allergic compounds.

18. Ethnic issues Effect of GM crops on biodiversity and environment b ) Risk that the transgene will transfer to microflora of human and animals. The GM crops may bring about changes in evolutionary patterns . There is a risk of transferring allergens from GM food to human and animals . There is a risk of “gene pollution” Religious issues ……..vegetarian people and some ethnic groups