Production of poly(3-hydroxybutyrate) by Rhodococcus qingshengii N9T-4 using the oligotrophic gene expression system
Abstract Rhodococcus qingshengii N9T-4 is a super oligotroph that grows on a completely inorganic basal medium without any additional carbon and nitrogen sources. This oligotrophy may facilitate low-carbon and low-cost bioprocessing for compounds of economic significance. In this study, an operon co...
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Nature Portfolio
2025-07-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-025-12197-y |
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| author | Akihiro Otsuka Izumi Orita Hiroya Yurimoto Nobuyuki Yoshida |
| author_facet | Akihiro Otsuka Izumi Orita Hiroya Yurimoto Nobuyuki Yoshida |
| author_sort | Akihiro Otsuka |
| collection | DOAJ |
| description | Abstract Rhodococcus qingshengii N9T-4 is a super oligotroph that grows on a completely inorganic basal medium without any additional carbon and nitrogen sources. This oligotrophy may facilitate low-carbon and low-cost bioprocessing for compounds of economic significance. In this study, an operon containing three Cupriavidus necator H16 genes that are involved in polyhydroxyalkanoate (PHA) biosynthesis, phaC1AB1, was expressed in N9T-4 cells under the promoter of aldA encoding an NAD+-dependent aliphatic aldehyde dehydrogenase, which is highly expressed under the oligotrophic conditions. The three proteins were successfully expressed, and Nile Red-stained colonies of the transformants showed the remarkable fluorescence, suggesting PHA accumulation in the cells. Only 3-hydroxybutyrate was detected during fatty-acid methyl ester analysis, confirming that poly(3-hydroxybutyrate) (20.8 ± 1.4 wt% of the dry cell weight) was produced in N9T-4 cells expressing the pha genes. Furthermore, carbon and nitrogen sources were examined for the PHA production; ethanol was the most effective carbon source. Transmission electron microscopy of the transformants revealed PHA granules in the PHA-producing N9T-4 cells. Although the use of ethanol may not seem oligotrophic, it did not affect oligotrophic gene expression; that is, oligotrophic metabolism proceeded in cells grown on ethanol. Thus, this study demonstrates the oligotrophic production of PHA, providing low-carbon and low-cost production of PHA. |
| format | Article |
| id | doaj-art-1acd6cd1e48842ae8b69898573259d91 |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Nature Portfolio |
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| spelling | doaj-art-1acd6cd1e48842ae8b69898573259d912025-08-20T03:42:49ZengNature PortfolioScientific Reports2045-23222025-07-011511710.1038/s41598-025-12197-yProduction of poly(3-hydroxybutyrate) by Rhodococcus qingshengii N9T-4 using the oligotrophic gene expression systemAkihiro Otsuka0Izumi Orita1Hiroya Yurimoto2Nobuyuki Yoshida3Department of Engineering, Graduate School of Integrated Science and Technology, Shizuoka UniversitySchool of Life Science and Technology, Institute of Science TokyoDivision of Applied Life Sciences, Graduate School of Agriculture, Kyoto UniversityDepartment of Engineering, Graduate School of Integrated Science and Technology, Shizuoka UniversityAbstract Rhodococcus qingshengii N9T-4 is a super oligotroph that grows on a completely inorganic basal medium without any additional carbon and nitrogen sources. This oligotrophy may facilitate low-carbon and low-cost bioprocessing for compounds of economic significance. In this study, an operon containing three Cupriavidus necator H16 genes that are involved in polyhydroxyalkanoate (PHA) biosynthesis, phaC1AB1, was expressed in N9T-4 cells under the promoter of aldA encoding an NAD+-dependent aliphatic aldehyde dehydrogenase, which is highly expressed under the oligotrophic conditions. The three proteins were successfully expressed, and Nile Red-stained colonies of the transformants showed the remarkable fluorescence, suggesting PHA accumulation in the cells. Only 3-hydroxybutyrate was detected during fatty-acid methyl ester analysis, confirming that poly(3-hydroxybutyrate) (20.8 ± 1.4 wt% of the dry cell weight) was produced in N9T-4 cells expressing the pha genes. Furthermore, carbon and nitrogen sources were examined for the PHA production; ethanol was the most effective carbon source. Transmission electron microscopy of the transformants revealed PHA granules in the PHA-producing N9T-4 cells. Although the use of ethanol may not seem oligotrophic, it did not affect oligotrophic gene expression; that is, oligotrophic metabolism proceeded in cells grown on ethanol. Thus, this study demonstrates the oligotrophic production of PHA, providing low-carbon and low-cost production of PHA.https://doi.org/10.1038/s41598-025-12197-y |
| spellingShingle | Akihiro Otsuka Izumi Orita Hiroya Yurimoto Nobuyuki Yoshida Production of poly(3-hydroxybutyrate) by Rhodococcus qingshengii N9T-4 using the oligotrophic gene expression system Scientific Reports |
| title | Production of poly(3-hydroxybutyrate) by Rhodococcus qingshengii N9T-4 using the oligotrophic gene expression system |
| title_full | Production of poly(3-hydroxybutyrate) by Rhodococcus qingshengii N9T-4 using the oligotrophic gene expression system |
| title_fullStr | Production of poly(3-hydroxybutyrate) by Rhodococcus qingshengii N9T-4 using the oligotrophic gene expression system |
| title_full_unstemmed | Production of poly(3-hydroxybutyrate) by Rhodococcus qingshengii N9T-4 using the oligotrophic gene expression system |
| title_short | Production of poly(3-hydroxybutyrate) by Rhodococcus qingshengii N9T-4 using the oligotrophic gene expression system |
| title_sort | production of poly 3 hydroxybutyrate by rhodococcus qingshengii n9t 4 using the oligotrophic gene expression system |
| url | https://doi.org/10.1038/s41598-025-12197-y |
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