Mutations That Alter the Bacterial Cell Envelope Increase Lipid Production
ABSTRACT Lipids from microbes offer a promising source of renewable alternatives to petroleum-derived compounds. In particular, oleaginous microbes are of interest because they accumulate a large fraction of their biomass as lipids. In this study, we analyzed genetic changes that alter lipid accumul...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Society for Microbiology
2017-07-01
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| Series: | mBio |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mBio.00513-17 |
| _version_ | 1819010172046016512 |
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| author | Kimberly C. Lemmer Weiping Zhang Samantha J. Langer Alice C. Dohnalkova Dehong Hu Rachelle A. Lemke Jeff S. Piotrowski Galya Orr Daniel R. Noguera Timothy J. Donohue |
| author_facet | Kimberly C. Lemmer Weiping Zhang Samantha J. Langer Alice C. Dohnalkova Dehong Hu Rachelle A. Lemke Jeff S. Piotrowski Galya Orr Daniel R. Noguera Timothy J. Donohue |
| author_sort | Kimberly C. Lemmer |
| collection | DOAJ |
| description | ABSTRACT Lipids from microbes offer a promising source of renewable alternatives to petroleum-derived compounds. In particular, oleaginous microbes are of interest because they accumulate a large fraction of their biomass as lipids. In this study, we analyzed genetic changes that alter lipid accumulation in Rhodobacter sphaeroides. By screening an R. sphaeroides Tn5 mutant library for insertions that increased fatty acid content, we identified 10 high-lipid (HL) mutants for further characterization. These HL mutants exhibited increased sensitivity to drugs that target the bacterial cell envelope and changes in shape, and some had the ability to secrete lipids, with two HL mutants accumulating ~60% of their total lipids extracellularly. When one of the highest-lipid-secreting strains was grown in a fed-batch bioreactor, its lipid content was comparable to that of oleaginous microbes, with the majority of the lipids secreted into the medium. Based on the properties of these HL mutants, we conclude that alterations of the cell envelope are a previously unreported approach to increase microbial lipid production. We also propose that this approach may be combined with knowledge about biosynthetic pathways, in this or other microbes, to increase production of lipids and other chemicals. IMPORTANCE This paper reports on experiments to understand how to increase microbial lipid production. Microbial lipids are often cited as one renewable replacement for petroleum-based fuels and chemicals, but strategies to increase the yield of these compounds are needed to achieve this goal. While lipid biosynthesis is often well understood, increasing yields of these compounds to industrially relevant levels is a challenge, especially since genetic, synthetic biology, or engineering approaches are not feasible in many microbes. We show that altering the bacterial cell envelope can be used to increase microbial lipid production. We also find that the utility of some of these alterations can be enhanced by growing cells in bioreactor configurations that can be used industrially. We propose that our findings can inform current and future efforts to increase production of microbial lipids, other fuels, or chemicals that are currently derived from petroleum. |
| first_indexed | 2024-12-21T01:08:02Z |
| format | Article |
| id | doaj.art-c291e532b948447ebf35d48997c96929 |
| institution | Directory Open Access Journal |
| issn | 2150-7511 |
| language | English |
| last_indexed | 2024-12-21T01:08:02Z |
| publishDate | 2017-07-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj.art-c291e532b948447ebf35d48997c969292022-12-21T19:20:59ZengAmerican Society for MicrobiologymBio2150-75112017-07-018310.1128/mBio.00513-17Mutations That Alter the Bacterial Cell Envelope Increase Lipid ProductionKimberly C. Lemmer0Weiping Zhang1Samantha J. Langer2Alice C. Dohnalkova3Dehong Hu4Rachelle A. Lemke5Jeff S. Piotrowski6Galya Orr7Daniel R. Noguera8Timothy J. Donohue9DOE Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, Wisconsin, USADOE Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, Wisconsin, USADOE Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, Wisconsin, USAPacific Northwest National Laboratory, Environmental Molecular Sciences Laboratory, Richland, Washington, USAPacific Northwest National Laboratory, Environmental Molecular Sciences Laboratory, Richland, Washington, USADepartment of Bacteriology, University of Wisconsin—Madison, Madison, Wisconsin, USADOE Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, Wisconsin, USAPacific Northwest National Laboratory, Environmental Molecular Sciences Laboratory, Richland, Washington, USADOE Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, Wisconsin, USADOE Great Lakes Bioenergy Research Center, University of Wisconsin—Madison, Madison, Wisconsin, USAABSTRACT Lipids from microbes offer a promising source of renewable alternatives to petroleum-derived compounds. In particular, oleaginous microbes are of interest because they accumulate a large fraction of their biomass as lipids. In this study, we analyzed genetic changes that alter lipid accumulation in Rhodobacter sphaeroides. By screening an R. sphaeroides Tn5 mutant library for insertions that increased fatty acid content, we identified 10 high-lipid (HL) mutants for further characterization. These HL mutants exhibited increased sensitivity to drugs that target the bacterial cell envelope and changes in shape, and some had the ability to secrete lipids, with two HL mutants accumulating ~60% of their total lipids extracellularly. When one of the highest-lipid-secreting strains was grown in a fed-batch bioreactor, its lipid content was comparable to that of oleaginous microbes, with the majority of the lipids secreted into the medium. Based on the properties of these HL mutants, we conclude that alterations of the cell envelope are a previously unreported approach to increase microbial lipid production. We also propose that this approach may be combined with knowledge about biosynthetic pathways, in this or other microbes, to increase production of lipids and other chemicals. IMPORTANCE This paper reports on experiments to understand how to increase microbial lipid production. Microbial lipids are often cited as one renewable replacement for petroleum-based fuels and chemicals, but strategies to increase the yield of these compounds are needed to achieve this goal. While lipid biosynthesis is often well understood, increasing yields of these compounds to industrially relevant levels is a challenge, especially since genetic, synthetic biology, or engineering approaches are not feasible in many microbes. We show that altering the bacterial cell envelope can be used to increase microbial lipid production. We also find that the utility of some of these alterations can be enhanced by growing cells in bioreactor configurations that can be used industrially. We propose that our findings can inform current and future efforts to increase production of microbial lipids, other fuels, or chemicals that are currently derived from petroleum.https://journals.asm.org/doi/10.1128/mBio.00513-17Rhodobacterbioreactorscell envelopefatty acidslipid synthesistwo-component regulatory systems |
| spellingShingle | Kimberly C. Lemmer Weiping Zhang Samantha J. Langer Alice C. Dohnalkova Dehong Hu Rachelle A. Lemke Jeff S. Piotrowski Galya Orr Daniel R. Noguera Timothy J. Donohue Mutations That Alter the Bacterial Cell Envelope Increase Lipid Production mBio Rhodobacter bioreactors cell envelope fatty acids lipid synthesis two-component regulatory systems |
| title | Mutations That Alter the Bacterial Cell Envelope Increase Lipid Production |
| title_full | Mutations That Alter the Bacterial Cell Envelope Increase Lipid Production |
| title_fullStr | Mutations That Alter the Bacterial Cell Envelope Increase Lipid Production |
| title_full_unstemmed | Mutations That Alter the Bacterial Cell Envelope Increase Lipid Production |
| title_short | Mutations That Alter the Bacterial Cell Envelope Increase Lipid Production |
| title_sort | mutations that alter the bacterial cell envelope increase lipid production |
| topic | Rhodobacter bioreactors cell envelope fatty acids lipid synthesis two-component regulatory systems |
| url | https://journals.asm.org/doi/10.1128/mBio.00513-17 |
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