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United States Department of Agriculture

Agricultural Research Service

Title: Natural Rubber Biosynthesis and a Profitable Guayule Crop

Authors
item Cornish, Katrina - YULEX CORPORATION
item McMahan, Colleen

Research conducted cooperatively with:
item Smart World Organics, Llc

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 31, 2007
Publication Date: July 21, 2007
Citation: Cornish, K., McMahan, C.M. 2007. Natural Rubber Biosynthesis and a Profitable Guayule Crop. Annual Meeting of the Phytochemical Society of North America.

Interpretive Summary: Natural rubber (cis-1,4-polyisoprene) is a biopolymer apparently synthesized in plants by a membrane-bound rubber transferase protein complex. The kinetic features of rubber transfereases make them a distinct class of cis-prenyl transferases. The structure of the particular allylic pyrophosphate initiator used to begin a new rubber polymer and the concentration of the initiator, monomer and divalent cation cofactor, all directly impact biosynthetic rate and final molecular weight and so directly affect both yield and quality. Guayule is a native rubber producing plant that produces high molecular weight rubber in rubber particles that contain very little extraneous protein. These rubber particles are now produced on a commercial scale as latex for the high-end medical and consumer products markets. However, processing large acreages of guayule shrub for latex production leaves around 90% of the biomass as a resin-rich crop residue. For cost-effective, large-scale and sustainable agriculture, 100% utilization of the entire crop is required. Guayule bagasse from the latex extraction process contains about 10% terpenoid resin which may be separately extracted and sold, or left in the bagasse as an added value. However, as the entire cost of producing the finely-ground, hard-wood, lignocellulosic bagasse is born by the value of the latex, the cost analyses for resin extraction and for conversion to ethanolic biofuels can be very favorable, especially in comparison with other lignocellulosic feedstocks such as rice straw, switch grass and corn stover.

Technical Abstract: Natural rubber (cis-1,4-polyisoprene) is a biopolymer apparently synthesized in plants by a membrane-bound rubber transferase protein complex. The kinetic features of rubber transfereases make them a distinct class of cis-prenyl transferases. The structure of the particular allylic pyrophosphate initiator used to begin a new rubber polymer and the concentration of the initiator, monomer and divalent cation cofactor, all directly impact biosynthetic rate and final molecular weight and so directly affect both yield and quality. Guayule is a native rubber producing plant that produces high molecular weight rubber in rubber particles that contain very little extraneous protein. These rubber particles are now produced on a commercial scale as latex for the high-end medical and consumer products markets. However, processing large acreages of guayule shrub for latex production leaves around 90% of the biomass as a resin-rich crop residue. For cost-effective, large-scale and sustainable agriculture, 100% utilization of the entire crop is required. Guayule bagasse from the latex extraction process contains about 10% terpenoid resin which may be separately extracted and sold, or left in the bagasse as an added value. However, as the entire cost of producing the finely-ground, hard-wood, lignocellulosic bagasse is born by the value of the latex, the cost analyses for resin extraction and for conversion to ethanolic biofuels can be very favorable, especially in comparison with other lignocellulosic feedstocks such as rice straw, switch grass and corn stover.

Last Modified: 10/31/2014
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