Overview of Yield Improvement Strategies for Secondary Metabolite Production in Plant Cell Culture

Abstract

SUMMARY 7Often when a project is initiated plant cell cultures produce low levels of a desired compound. For the project to move to a commercial level, time-dependent volumetric yields (mg.product/L-day) must typically be increased several orders of magnitude. Typically, no single growth enhancing strategy will give such a large increase, but in many cases the simultaneous application of multiple-strategies results in a synergistic interaction and the large increases necessary to bring yields in a plant cell culture process to a useful level. Yield improvement strategies include selection of stable, high-yielding variants; manipUlation of medium components and/or gas phase composition; metabolic manipulation through gene manipulation or use of inhibitors; precursor feeding; use of elicitors; in situ product removal; and use of immobilization or more differentiated or organized plant material. INTRODUCTIONThe commercial application of plant ceIl cultures is likely to be in three areas: (1) facile production of elite plants; (2) as a tool to generate sufficient quantities of metabolites for screening or characterization in a drug discovery program; and (3) for the commercial scale production of a metabolite. In this symposium and book we are focused on the third objective, particularly as it applies to food ingredients. Reviews on food ingredient production and a possible role for plant cell cultures has been published elsewhere

Biotechnological Flavour Generation

“…Progress was achieved by the selection of high-yielding cell lines, variation of the chemical and physical environment, supplementation of precursors and elicitors, in situ product removal and immobilisation techniques. Simultaneous application of several different strategies may result in a synergistic response and a pronounced secondary metabolite formation (Berger, 1995;Pedersen et al, 1999;Shuler, 1999;Verpoorte et al, 1999). Current proposals to improve bioreactor designs for suspension cultures and for organised cultures were presented by Scragg (2007).…”

Development of a Low Capital Investment Reactor System: Application for Plant Cell Suspension Culture

“…The differential between production costs and product market value is the dominant driving force for drug discovery and development of potential bioprocesses. The importance of production costs is reflected in the economic observation that the volumetric productivity of a wide range of biologically produced products is about the same at $0.17 L −1 ·day −1 (1, 2). The expense of biological production is a motivation for pursuing chemical synthesis when possible; however, the complexity of synthesis of many natural products often makes this route equally costly.…”