5. Advantages of biotransformation

The advantages consist of the production of novel compounds, improvement in the productivity of desired compound and overcoming the problems related with chemical synthesis. Biotransformation studies lead to basic information to elucidate the biosynthetic pathway, and catalysis can be carried out under mild conditions, thus reducing undesired by-products, energy, safety and costs.

6. Factors influencing biotransformation

6.1. 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. Yokoyama (1991) reported that antioxidant, such as gallic acid, ascorbic acid, cystein and tannins could increase the production of arbutin when hydroquinone was added to the cell culture.

6.2. Selection of Plant Species

The capacity for biotransformation is diverse among plant species. Tabata et.al (1988) reported that among seven species of plant cell cultures, only Datura had capacity to biotransform coumarins, flavonoids, phenolic acids and anthraquinones.

6.3. Immobilized plant cells

It has distinct advantages e.g. reuse of the expensive biocatalyst, continuous process, and process control is simplified.

6.4. Root culture

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