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Characterization and functional expression of a rubber degradation gene of a Nocardia degrader from a rubber-processing factory
- Linh, Dao Viet, Huong, Nguyen Lan, Tabata, Michiro, Imai, Shunsuke, Iijima, Sou, Kasai, Daisuke, Anh, To Kim, Fukuda, Masao
- Journal of bioscience and bioengineering 2017 v.123 no.4 pp. 412-418
- Escherichia coli, Nocardia farcinica, aldehydes, enrichment culture, gel chromatography, genes, heterologous gene expression, latex, nucleotide sequences, reverse transcriptase polymerase chain reaction, rubber, staining, transcription (genetics), wastes, Vietnam
- A rubber-degrading bacterial consortium named H2DA was obtained from an enrichment culture with natural rubber latex and rubber-processing factory waste in Vietnam. Gel permeation chromatography analysis revealed that only the strain NVL3 degraded synthetic poly(cis-1,4-isoprene) into low-molecular-weight intermediates among the three strains found in the H2DA. The 16S-rRNA gene sequence of NVL3 showed the highest identity with that of Nocardia farcinica DSM 43665ᵀ. NVL3 accumulated aldehyde intermediates from synthetic poly(cis-1,4-isoprene) on a rubber-overlay plate as indicated by Schiff's staining. NVL3 also degraded deproteinized natural rubber into low-molecular-weight aldehyde intermediates. A latex-clearing protein (lcp) gene ortholog was identified within the genome sequence of NVL3, and it showed a moderate amino-acid identity (54–75%) with the lcp genes from previously reported rubber degraders. The heterologous expression of the NVL3 lcp in Escherichia coli BL21(DE3) allowed us to purify the 46.8-kDa His-tagged lcp gene product (His-Lcp). His-Lcp degraded synthetic poly(cis-1,4-isoprene) and accumulated aldehyde intermediates from deproteinized natural rubber suggesting the functional expression of the lcp gene from a Nocardia degrader in E. coli. Quantitative reverse transcription PCR analysis indicated the strong transcriptional induction of the lcp gene in NVL3 in the presence of synthetic poly(cis-1,4-isoprene). These results suggest the involvement of the lcp gene in rubber degradation in NVL3.