Decomposition of Guayule Resins by Microorganisms

Abstract

A process for the aerobic biological decomposition of guayule (Parthenium argentatum Gray) prior to extraction of the rubber by mechanical means was patented by Spence (1933). The process, called retting because of the loose analogy to the retting of flax for the production of linen fiber, produced a marked decrease in the impurities of the rubber and improved the physical properties of the vulcanized rubber. It also decreased the resinous acetone-soluble contaminant from about 20 per cent of the crude rubber product to about 10 per cent, but no conclusions were drawn as to the agent responsible for the changes in composition and properties. The work reported in this paper is one phase of a reinvestigation of the retting of guayule by the natural microflora; it deals specifically with the decomposition of guayule resins. The resin of guayule is a mixture of acetone-soluble constituents of the plant. When the shrub is injured a clear resin exudes and dries. Other resin preparations were made by exhaustive extraction of guayule rubber with acetone and removal of the solvent. A variety of microorganisms normally present in the soil flora have been shown to oxidize compounds ordinarily considered relatively resistant to biochemical oxidation. Numerous species of bacteria have been found to oxidize phenols, and aromatic, alicyclic and aliphatic hydrocarbons. The literature on these subjects prior to 1940 is briefly reviewed by Bushnell and Haas (1941). Many species of actinomycetes oxidize aliphatic hydrocarbons (Umbreit, 1939) and the olefinic rubber hydrocarbon (

The Environmental Acinetobacter baumannii Isolate DSM30011 Reveals Clues into the Preantibiotic Era Genome Diversity, Virulence Potential, and Niche Range of a Predominant Nosocomial Pathogen

“…Here, we traced DSM30011 origins to a strain originally deposited at the NRRL in 1943 as Achromobacter lacticum 4-h (NRRL B-551, Agricultural Research Service Culture Collection, ARS, U.S. Department of Agriculture; see supplementary table S1 , Supplementary Material online for details). This strain was isolated after enrichment of the resin-degrading natural microbiota responsible of the aerobic decomposition of guayule ( Parthenium argentatum Gray), a resin-producing angiosperm of the Asteraceae family common to arid and semiarid areas of the south-western United States and north-central Mexico ( Allen etal. 1944 ; Naghski etal.…”

Aerobic Decomposition of Guayule Shrub ( Parthenium argentatum Gray)

“…was the predominating mold. It appears highly significant that this organism should also be capable of attacking guayule resin (Allen, Naghski, and Hoover, 1944). It was present in counts of 106 to 106 per gram in all experiments.…”

“…Addition of glucose to the nutrient agar failed to improve the substrate. Resin emulsion agar (Allen, Naghski, and Hoover, 1944) was also unsatisfactory for total counts because the colonies developed more slowly, although it proved useful for detection of resin-digesting organisms. All microbiological data are expressed on a wet-weight basis.…”

“…Identity of microorganisms Although our primary aim was the study of the biochemical activities of the natural flora, some of the 1108 cultures isolated were further studied and classified. Those organisms capable of attacking the "resin" of guayule rubber and of the guayule plant are discussed by Allen, Naghski, and Hoover (1944).…”

“…Addition of glucose to the nutrient agar failed to improve the substrate. Resin emulsion agar (Allen, Naghski, and Hoover, 1944) was also unsatisfactory for total counts because the colonies developed more slowly, although it proved useful for detection of resin-digesting organisms. All microbiological data are expressed on a wet-weight basis.Appropriate dilutions were made for the determination of fungi in poured plates of glucose-peptone-acid agar, adjusted to pH 4.5 with H2SO4.As the temperatures at which the experiments were conducted were at the upper limit for the mesophilic microorganisms and the lower limit for the thermophilic forms, plates for bacteriological analysis were poured and incubated at the average temperature of the retting shrub.…”