Hevea brasiliensis rubber tree

Natural rubber is obtained from the bark of the rubber tree, Hevea brasiliensis, grown on enormous plantations in Southeast Asia. 

Rubber—an unusual name for an unusual substance—is a naturally occurring aikene polymer produced by more than 400 different plants. The major source is the so-called rubber tree, Hevea brasiliensis, from which the crude material is harvested as it drips from a slice made through the bark. The name rubber was coined by Joseph Priestley, the discoverer of oxygen and early researcher of rubber chemistry, for the simple reason that one of rubber s early uses was to tub out pencil marks on paper. 

Hasslacher, M., Schall, M., Hayn, M. et al. (1997) High-level intracellular expression of hydroxynitrile lyase from the tropical rubber tree Hevea brasiliensis in microbial hosts. Protein Expression and Purification, 11, 61-71. 

In 1994, the worldwide consumption of rubber was approximately 14.5 million tons a year, of which about 40% consisted of natural rubber. Natural rubber is produced as latex by tropical rubber trees (Hevea brasiliensis). It is processed locally and therefore the quality of natural rubber fluctuates remarkably [ 140]. Due to increasing demand for rubbers, combined with a decreasing production capacity in Asia and a vast increase in labor costs, the price of natural rubber is still rising sharply. In 1990-1994, the average price of natural rubber was about 0.38 /lb, while in 1996 it was already over 0.80 /lb. The remaining 60% of the articles were manufactured from synthetic petroleum-based rubbers such as isoprene rubber, styrene-butadiene rubber, chloroprene rubber and polyurethanes. The quality of synthetic rubbers is constant, and their price varies between 2 and 5 US per kilogram [137-140]. 

Diene polymers refer to polymers synthesized from monomers that contain two carbon-carbon double bonds (i.e., diene monomers). Butadiene and isoprene are typical diene monomers (see Scheme 19.1). Butadiene monomers can link to each other in three ways to produce ds-1,4-polybutadiene, trans-l,4-polybutadi-ene and 1,2-polybutadiene, while isoprene monomers can link to each other in four ways. These dienes are the fundamental monomers which are used to synthesize most synthetic rubbers. Typical diene polymers include polyisoprene, polybutadiene and polychloroprene. Diene-based polymers usually refer to diene polymers as well as to those copolymers of which at least one monomer is a diene. They include various copolymers of diene monomers with other monomers, such as poly(butadiene-styrene) and nitrile butadiene rubbers. Except for natural polyisoprene, which is derived from the sap of the rubber tree, Hevea brasiliensis, all other diene-based polymers are prepared synthetically by polymerization methods. 

Weir, J. R., Pathological Survey of the Para Rubber Tree (Hevea brasiliensis)... 

The ability to synthesize particular isoprenoids is limited to a few species of plants and animals. For example, rubber is only formed by a few plant species, including the rubber tree Hevea brasiliensis). Several isoprenoids that are required by animals for me-... 

Broekaert, W., Lee, H., Kush, A., Chua, N. Raikhel, N. (1990). Wound-induced accumulation of mRNA containing a hevein sequence in lactifers of rubber tree (Hevea brasiliensis). Proceedings of the National Academy of Sciences (USA) 87, 7633-7. 

The highest reported heterologous production of a protein in yeast comes from the work by Hasslacher et al. (1997). The enzyme hydroxynitrile lyase (Hnl) from the tropical rubber tree Hevea brasiliensis was reported to produce levels of 22g/L intracellularly in P. pastoris. In the same study, S. cerevisiae and E. coli were tested in parallel experiments but were not competitive. Levels of proteins produced by yeasts have more typically been in the range of 1-15 g/L (Schmidt, 2004). A list of reported yields for expression of proteins in P. pastoris is provided by Cregg at http / faculty.kgi.edu/cregg/index.htm... 

AdiwUaga, K. and Kush, A. (1996) Cloning and characterization of cDNA encoding famesyl diphosphate synthase from rubber tree (Hevea brasiliensis). Plant Mol. Biol., 30,935- 6. 

Rubber. Rubber is an organic substance, obtained mainly from tlie sap of the rubber tree, Hevea brasiliensis. Rubber consists of very long molecules, which are polymers of isoprene, CgHg. The structure ol isoprt ne is... 

The first described (S)-oxynitrilase which fulfils these requirements was isolated from the rubber tree Hevea brasiliensis [16,32,33, 61]. This oxynitrilase accepts ahphatic as well as aromatic aldehydes of varying structure and chain length [151 -153] in addition to ketones [68]. 

Allergy to natural rubber latex, first reported in 1989 in the United States, is a common cause of occupational allergy for health care workers. Natural rubber is a processed plant product from the commercial rubber tree, Hevea brasiliensis. Latex allergens are proteins found in both raw latex and the extracts used in finished rubber products. Latex gloves are the largest single source of exposure to the protein allergens. ... 

These two methods involve the potential release of toxic HCN during the reaction and a cleaner as well as a safer method is to use acetone cyanohydrin 128 as a cyanide transfer reagent. The enzyme from the Brazilian rubber tree Hevea brasiliensis, called a hydroxynitrile lyase, catalyses cyanohydrin formation from aliphatic as well as aromatic aldehydes.40... 

H. Alenius, N. Kalkkinen, M. Lukka, T. Reunala, K. Turjanmaa, S. Makinen-Kiljunen, E. Yip, and T. Palosuo, Prohevein from the rubber tree (Hevea brasiliensis) is a major latex allergen, Clin. Exp. Allergy, 25 (1995) 659-665. 

Rubber Rubber dust Rubber, natural Definition Coagulated and dried exudate of the rubber tree, Hevea brasiliensis natural rubber contains 89-92% elastomeric hydrocarbon (cis-1,4-polyisoprene)... 

DSM developed a recombinant oxynitrilase from the rubber tree (Hevea brasiliensis), with which it is possible to produce the cyanohydrin of (S)-3-phenoxy-benzaldehyde with an enantiomeric excess of 98.5 % and a space/time-yield of 1,000 g/l/day. [113]... 

Rubber hydrocarbon is the principle component of raw rubber. The subject is discussed in greater detail in Chapter 7. Natural rubber is 97% cw-l,4-polyisoprene. It is obtained by tapping the bark of rubber trees (Hevea brasiliensis) and collecting the exudate, a latex consisting of about 32-35% rubber. A similar material can also be found in the sap of many other plants and shrubs. The structure of natural rubber has been investigated over 100 years, but it was only after 1920, however, that the chemical structure was elucidated. It was shown to be a linear polymer consisting of head-to-tail links of isoprene units, 98% bonded 1,4. 

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