Genetic manipulation chemical synthesis

Classification by End Use Chemical reactors are typically used for the synthesis of chemical intermediates for a variety of specialty (e.g., agricultural, pharmaceutical) or commodity (e.g., raw materials for polymers) applications. Polymerization reactors convert raw materials to polymers having a specific molecular weight and functionality. The difference between polymerization and chemical reactors is artificially based on the size of the molecule produced. Bioreactors utilize (often genetically manipulated) organisms to catalyze biotransformations either aerobically (in the presence of air) or anaerobically (without air present). Electrochemical reactors use electricity to drive desired reactions. Examples include synthesis of Na metal from NaCl and Al from bauxite ore. A variety of reactor types are employed for specialty materials synthesis applications (e.g., electronic, defense, and other). 

The wide array of 16-membered macrolides has amply supplied chemists with starting materials for structural modifications, and the extensive structural variations have provided a wealth of ideas from which hybrid molecules have been conceived. In addition to synthesis by purely chemical means, structural modifications have been effected by bioconversions, alterations of biosynthetic pathways, and genetic manipulations of macrolide-producing micro-organisms [13]. These natural structural variations have also contributed to a better understanding of structure-activity relationships and have been used to successfully guide synthetic programmes. Finally, these complex natural products have inspired numerous... 

Concerning the chemical synthesis of this type of compounds, this appears non viable in economic terms and, taking into account that secondary metabolites are often produced in very low amounts in the mother plants, the genetic modification of the terpenoid biosynthetic pathway would be an attractive alternative to obtain a continuous source of these valuable metabolites because it offers the possibility of manipulating cells, tissues or even complete organisms in order to obtain a continuous and accurate source of these secondary metabolites. 

The directed synthesis of deoxyribonucleic acid (DNA) and its manipulation for genetic engineering would be impossible without enzyme catalysis. There is a range of restriction enzymes which can break DNA strands at specific points defined by the local base sequence, as well as ligases which can rejoin the broken ends where new base sequences are inserted, and they are essential catalysts. They complement the chemical synthesis of the oligonucleotides (small segments of DNA) which are inserted. A discussion of the technique is outside the scope of this chapter, largely because the... 

Microbial production of carotenoids is an environmentally friendly method compared to chemical methods. The availability of carotenoid genes from carotenogenic microbes has made possible the synthesis of carotenoids in non-carotenogenic microbes [80]. E. coli, because of its ease for genetic manipulation, is considered a suitable host for carotenoid production and is able to make various carotenoids such as lycopene, P-carotene, canthaxanthin, zeaxanthin, and astaxanthin [81-83]. 

---