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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.