Gary M. Hewitt

Studies with plant cell cultures of Podophyllum peltatum L. II: Biotransformation of dibenzylbutanolides to lignans. Development of a biological factory' for lignan synthesis

An efficient and versatile synthetic route to appropriate dibenzylbutanolides suitable for biotransformation to lignans as potential intermediates for the syntheses of the clinical anti-cancer drug etoposide has been developed. Biotransformation of such substrates, for example 10, with cell cultures of Podophyllum peltatum affords a potentially exciting route to this drug. Of particular significance is the development of a semi-continuous fermentation process with these plant cells wherein successive additions of substrate and isolation of end products can be pursued with a given batch of cells and over a period of several months

Anti-inflammatory oleanane triterpenes from Tripterygium wilfordii cell suspension cultures by fungal elicitation

SummaryTreatment of cell suspension cultures of Tripterygium wilfordii with an autoclaved Botrytis sp. homogenate rapidly increased the synthesis of a family of oleanane and friedelane triterpenes, including the antiinflammatory oleanane triterpene 3β,22α-dihydroxyolean-12-en-29-oic acid. This compound exceeded 30 mg · l−1 in 13 day elicitations with 12 l bioreactors, in contrast to control levels of less than 5 mg · l−1. Cell cultures treated with the fungal elicitor provided higher triterpene yields in less time than cultures in a diterpene production medium or whole plants. Elicited production has been developed for commercial application in light of the successful treatment of rheumatoid arthritis with Tripterygium extracts.

The recycling air lift transfer fermenter for plant cells

SummarySuspension cultures of Triptergium wildordii require oxygen at a rate of 3.2 to 0.8 uL of oxygen/mg dry wt of cells/hr. A recycling air lift fermenter was developed in which the major volume of air required to lift the cells is recycled air. Sufficient new air is fed to meet the oxygen requirements of the cells. Such a fermenter design supports the growth of a large production of cells suitable for batch or continuous feeding.