Production of Natural Rubber from Para Rubber Tree

Plant Biotechnology 26, 67–70 (2009)

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Production of natural rubber from Para rubber tree
Yasuyuki Hayashi
Bridgestone Corporation, Kodaira, Tokyo 187-8531, Japan E-mail: [e-mail] Tel: [phone] Fax: [phone]

Received December 22, 2008; accepte January 27, 2009 (Edited by H. Suzuki)

Abstract Natural rubber is one of the most important polymers produced by plants because it is a strategic raw material used in more than 40,000 products. It has unique properties as a polymer owing to its specific structure, its high molecular weight and yet-to-be-defined contributions of minor components in the latex. Among over 2500 rubber-producing plant species, the Para rubber tree (Hevea brasiliensis Muell. Arg.) is presently the only commercial source of natural rubber. The objective of this review is to provide readers with information on the newest trends and market conditions of natural rubber and also explain the historical background and a global view of Hevea breeding and genetics, together with information about alternative resources. Key words: Alternative rubber sources, biotechnology, breeding, end-use markets, Hevea brasiliensis, natural rubber, supply and demand.

Natural rubber as a composite of poly cisisoprene and minor components
Natural rubber is a biopolymer consisting of isoprene units (C5H8)n linked together in a 1,4 cis-configuration. Various latex-producing plants synthesize natural rubber in their specifically differentiated cells in a manner such that C5-monomer units, isopentenyl pyrophosphate (IPP) molecules, are sequentially condensed into allylic primers, like FPP or GPP by cis-prenyltransferase (Figure 1) (Takahashi 2006). Not only poly cis-isoprene molecules, but also other cellular components, are included in the latex. Namely, natural rubber is, in a sense, a composite of these components, while synthetic rubber is almost simply composed of poly-isoprene with not more than 90% of cis-bond.

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