Bacterial degradation of poly(trans-1,4-isoprene) (gutta percha)

Abstract

Gutta percha, the trans-isomer of polyisoprene, is being used for several technical applications due to its resistance to biological degradation. In the past, several attempts to isolate micro-organisms capable of degrading chemically pure poly(trans-1,4-isoprene) have failed. This is the first report on axenic cultures of bacteria capable of degrading gutta percha. From about 100 different habitats and enrichment cultures, six bacterial strains were isolated which utilize synthetic poly(trans-1,4-isoprene) as sole carbon and energy source for growth. All isolates were assigned to the genus Nocardia based on 16S rRNA gene sequences. Four isolates were identified as strains of Nocardia nova (L1b, SH22a, SEI2b and SEII5a), one isolate was identified as a strain of Nocardia jiangxiensis (SM1) and the other as a strain of Nocardia takedensis (WE30). In addition, the type strain of N. takedensis obtained from a culture collection (DSM 44801 T ) was shown to degrade poly(trans-1,4-isoprene). Degradation of poly(trans-1,4-isoprene) by these seven strains was verified in mineralization experiments by determining the release of CO 2 . All seven strains were also capable of mineralizing poly(cis-1,4-isoprene) and to use this polyisoprenoid as a carbon and energy source for growth. Mineralization of poly(trans-1,4-isoprene) after 80 days varied from 3 % (strain SM1) to 54 % (strain SEI2b) and from 34 % (strain L1b) to 43 % (strain SH22a) for the cis-isomer after 78 days. In contrast, Gordonia polyisoprenivorans strain VH2, which was previously isolated as a potent poly(cis-1,4-isoprene)-degrading bacterium, was unable to degrade poly(trans-1,4-isoprene). Scanning electron microscopy revealed cavities in solid materials prepared from poly(trans-1,4-isoprene) and also from poly(cis-1,4-isoprene) after incubation with N. takedensis strain WE30 or with N. nova strain L1b, whereas solid poly(trans-1,4-isoprene) material remained unaffected if incubated with G. polyisoprenivorans strain VH2 or under sterile conditions.

Involvement of Two Latex-Clearing Proteins during Rubber Degradation and Insights into the Subsequent Degradation Pathway Revealed by the Genome Sequence of Gordonia polyisoprenivorans Strain VH2

“…The IR particles were then fully dried again. For growth experiments in liquid media, the IR was frozen in liquid nitrogen and then milled to a defined range of grain sizes (between 63 and 500 m) according to the method of Warneke et al (93). These grains were used to cultivate G. polyisoprenivorans and its derived mutants in liquid mineral salts medium (MSM) (80) containing 0.2% (wt/vol) IR as the sole carbon and energy source.…”

Gutta-Percha-based Adhesive for Laminated Wood Production

“…The component with the largest concentration was 1,3-butadiene, 2-methyl-(CAS) isoprene. Gutta-percha has an isomer structure of trans-1,4-isoprene (Warneke et al 2007) or trans-1,4-poly (methyl buta 1,3-diene (polyisoprene) (Cowd 1982;Rose and Steinbuchel 2005). The glass transition (Tg) and melting temperatures of gutta-percha resin were -56.75 °C and 51.67 °C, respectively.…”

Functional Identification of Rubber Oxygenase (RoxA) in Soil and Marine Myxobacteria

“…Streptomycetes and related actinobacteria are well-known for their potential to degrade biopolymers, such as proteins, polysaccharides, or polyesters. Previous analysis of the distribution of rubber-degrading bacteria showed that, indeed, members of the actinobacteria are frequently able to utilize polyisoprene as a source of carbon and energy (1,6,(22)(23)(24). As far as it has been investigated, most-if not all-of the rubber-degrading actinobacteria employ latex-clearing protein (Lcp) as the catalyst for the primary attack of polyisoprene (6,7).…”