Biotransformation

BIOTRANSFORMATION IN PLANT

1. BIOTRANSFORMATION PRESENTED BY : SRISHTI AGGRAWAL M.SC BOTANY 1702443 FACULTY OF SCIENCE DEI,AGRA PRESENTED TO : Dr.P.K DANTU FACULTY OF SCIENCE DEI,AGRA

2. introduction Biotransformation is a chemical reaction catalysed by cells ,organs or enzymes. It is defined as a process through which the functional g roups of organic compounds are modified by living cells to a chemically different product. It explores the unique properties of biocatalysts, namely their stereo region specificity and their their ability to carry out reactions at no extreme pH values and temperature.

3. It may be used to carry out specific conversions of complex substrates using plant,animal or microbial cells or purified enzymes as catalysts. The production of metabolities ,fine chemicals and pharmaceutical can be achieved by biotransformation using biological catalysts.

4. For a successful and viable process,the following prerequisites must be met. The culture must have the essential enzymes. The substrate must not be toxic to the cell culture. The substrate must reach the appropriate cellular compartment of the cell. The rate of product formation must be faster than its further metabolism .

5. Biotransformation using plant cell and organ cultures. The biotransformation rates on a variety of factors:- The amount of enzyme activity present, localization of enzymes, Elicitation, Permeability, pH variation, osmotic effects Some eg : P eganum harmala cell culture converted geranyl acetate to geranitol and linalyl acetate to linalool and terpinol .

6. Biotransformation using immobilized cell culture Entire cells offer the chance to implement multistep biotransformation and to utilize and recycle essential cofactors and coenzymes Isolated enzymes may be sensitive to denaturing conditions including pH,heat and specific organic solvents. In order to be useful in biotransformation reactions, biocatalysts need to be stable and reusable. Use of whole cell immobilized system may help overcome some stability problems

7. Immobilized plant cells have some additional advantages over freely suspended cells; they are more resistant to shear damage and can be used repeatedly over a prolonged period. Complete cell immobilization may also create adverse conditions under w hich secondary metabolite production may be improved. A very common method for immobilization of plant cells are gel entrapement by ion exchange, precipitation, polymerization .

8. Genetic engineering approaches Biotransformation capacity of cell cultures can be further improved by changing the following parameters:- Cell selection Elicitation Permabilization Radiation pH of medium Osmotic shock A more basic approach is transfer of genes that code for the key enzymes catalyzing the desired biosynthetic reactions into a fungal or bacterial cell because their ability to produce high amounts of enzymes ( Pras et al,1995)

9. Hashimoto et al,1993 explain the expression of hyoscyamine 6-b-hydroxylase in E . coli . This recombinant bacterium was capable to convert hyoscyamine to scopoamine . Subsequently, this cloned gene has been transferred to Atropa belladonna and expressed constitutively.

10. Advantages of biotransformation Production of novel compound Improvement in the productivity of desired compound Overcoming the problems relates with chemical synthesis.

11. Factors influencing biotransformation Improvement of cell viability Many substances are harmful to cultured cells. So it is necessary to decrease the toxicity in order to increase the yield of the product. Sugar can increase cell viability during glycosylation of phenolic compounds. Antioxidants can improve cell viability and increase product formation in the biotransformation of phenolics .

12. Selection of plant species Tabata et al (1988) reported that among 7 sp. Of plant cell cultures , only Dathura had capacity to biotransforme flavonoids, phenolic acids and anthraquinones . Immobilized plant cells It has distinct advantages e.g.reuse of the expensive biocatalyst, continuous process, and process control is simplified.

13. Root culture Cell suspension culture has excellent biotransformation capacity for glycosylation. Furuya et al (1989) have found that the root culture showed higher glycosylation activity than cell culture.