Linh Dao Viet, Huong Nguyen Lan, Tabata Michiro, Imai Shunsuke, Iijima Sou, Kasai Daisuke, Anh To Kim, Fukuda Masao
Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan; School of Biotechnology and Food Technology, Hanoi University of Science and Technology, Hanoi, Viet Nam.
School of Biotechnology and Food Technology, Hanoi University of Science and Technology, Hanoi, Viet Nam.
J Biosci Bioeng. 2017 Apr;123(4):412-418. doi: 10.1016/j.jbiosc.2016.11.012. Epub 2017 Jan 3.
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 43665. 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.
一个名为H2DA的橡胶降解细菌群落是从越南天然橡胶乳胶和橡胶加工厂废料的富集培养物中获得的。凝胶渗透色谱分析表明，在H2DA中发现的三种菌株中，只有NVL3菌株能将合成聚（顺式-1,4-异戊二烯）降解为低分子量中间体。NVL3的16S-rRNA基因序列与诺卡氏菌DSM 43665的序列具有最高的同源性。如席夫氏染色所示，NVL3在橡胶覆盖平板上从合成聚（顺式-1,4-异戊二烯）中积累醛类中间体。NVL3还能将脱蛋白天然橡胶降解为低分子量醛类中间体。在NVL3的基因组序列中鉴定出一个乳胶清除蛋白（lcp）基因直系同源物，它与先前报道的橡胶降解菌的lcp基因具有中等的氨基酸同源性（54-75%）。NVL3的lcp在大肠杆菌BL21(DE3)中的异源表达使我们能够纯化46.8 kDa的His标签lcp基因产物（His-Lcp）。His-Lcp能降解合成聚（顺式-1,4-异戊二烯）并从脱蛋白天然橡胶中积累醛类中间体，这表明来自诺卡氏菌降解菌的lcp基因在大肠杆菌中具有功能表达。定量逆转录PCR分析表明，在合成聚（顺式-1,4-异戊二烯）存在的情况下，NVL3中lcp基因有强烈的转录诱导。这些结果表明lcp基因参与了NVL3中的橡胶降解。
