1
|
Advancing Desulfurization in the Model Biocatalyst Rhodococcus qingshengii IGTS8 via an In Locus Combinatorial Approach. Appl Environ Microbiol 2023; 89:e0197022. [PMID: 36688659 PMCID: PMC9973023 DOI: 10.1128/aem.01970-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Biodesulfurization poses as an ideal replacement to the high cost hydrodesulfurization of the recalcitrant heterocyclic sulfur compounds, such as dibenzothiophene (DBT) and its derivatives. The increasingly stringent limits on fuel sulfur content intensify the need for improved desulfurization biocatalysts, without sacrificing the calorific value of the fuel. Selective sulfur removal in a wide range of biodesulfurization strains, as well as in the model biocatalyst Rhodococcus qingshengii IGTS8, occurs via the 4S metabolic pathway that involves the dszABC operon, which encodes enzymes that catalyze the generation of 2-hydroxybiphenyl and sulfite from DBT. Here, using a homologous recombination process, we generate two recombinant IGTS8 biocatalysts, harboring native or rearranged, nonrepressible desulfurization operons, within the native dsz locus. The alleviation of sulfate-, methionine-, and cysteine-mediated dsz repression is achieved through the exchange of the native promoter Pdsz, with the nonrepressible Pkap1 promoter. The Dsz-mediated desulfurization from DBT was monitored at three growth phases, through HPLC analysis of end product levels. Notably, an 86-fold enhancement of desulfurization activity was documented in the presence of selected repressive sulfur sources for the recombinant biocatalyst harboring a combination of three targeted genetic modifications, namely, a dsz operon rearrangement, a native promoter exchange, and a dszA-dszB overlap removal. In addition, transcript level comparison highlighted the diverse effects of our genetic engineering approaches on dsz mRNA ratios and revealed a gene-specific differential increase in mRNA levels. IMPORTANCE Rhodococcus is perhaps the most promising biodesulfurization genus and is able to withstand the harsh process conditions of a biphasic biodesulfurization process. In the present work, we constructed an advanced biocatalyst harboring a combination of three genetic modifications, namely, an operon rearrangement, a promoter exchange, and a gene overlap removal. Our homologous recombination approach generated stable biocatalysts that do not require antibiotic addition, while harboring nonrepressible desulfurization operons that present very high biodesulfurization activities and are produced in simple and low-cost media. In addition, transcript level quantification validated the effects of our genetic engineering approaches on recombinant strains' dsz mRNA ratios and revealed a gene-specific differential increase in mRNA levels. Based on these findings, the present work can pave the way for further strain and process optimization studies that could eventually lead to an economically viable biodesulfurization process.
Collapse
|
2
|
Wang Z, Zeng Y, Jia H, Yang N, Liu M, Jiang M, Zheng Y. Bioconversion of vitamin D 3 to bioactive calcifediol and calcitriol as high-value compounds. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:109. [PMID: 36229827 PMCID: PMC9563128 DOI: 10.1186/s13068-022-02209-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 10/04/2022] [Indexed: 11/07/2022]
Abstract
Biological catalysis is an important approach for the production of high-value-added compounds, especially for products with complex structures. Limited by the complex steps of chemical synthesis and low yields, the bioconversion of vitamin D3 (VD3) to calcifediol and calcitriol, which are natural steroid products with high added value and significantly higher biological activity compared to VD3, is probably the most promising strategy for calcifediol and calcitriol production, and can be used as an alternative method for chemical synthesis. The conversion efficiency of VD3 to calcifediol and calcitriol has continued to rise in the past few decades with the help of several different VD3 hydroxylases, mostly cytochrome P450s (CYPs), and newly isolated strains. The production of calcifediol and calcitriol can be systematically increased in different ways. Specific CYPs and steroid C25 dehydrogenase (S25DH), as VD3 hydroxylases, are capable of converting VD3 to calcifediol and calcitriol. Some isolated actinomycetes have also been exploited for fermentative production of calcifediol and calcitriol, although the VD3 hydroxylases of these strains have not been elucidated. With the rapid development of synthetic biology and enzyme engineering, quite a lot of advances in bioproduction of calcifediol and calcitriol has been achieved in recent years. Therefore, here we review the successful strategies of promoting VD3 hydroxylation and provide some perspective on how to further improve the bioconversion of VD3 to calcifediol and calcitriol.
Collapse
Affiliation(s)
- Zheyi Wang
- grid.9227.e0000000119573309State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049 China
| | - Yan Zeng
- grid.9227.e0000000119573309State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101 China
| | - Hongmin Jia
- China Animal Husbandry Industry Co. Ltd, Beijing, 100095 China
| | - Niping Yang
- grid.256885.40000 0004 1791 4722School of Life Sciences, Hebei University, No. 180 Wusi Dong Road, Baoding, 071002 China
| | - Mengshuang Liu
- grid.9227.e0000000119573309State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049 China
| | - Mingyue Jiang
- grid.9227.e0000000119573309State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101 China ,grid.410726.60000 0004 1797 8419University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing, 100049 China
| | - Yanning Zheng
- grid.9227.e0000000119573309State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing, 100101 China
| |
Collapse
|
3
|
Liang Y, Yu H. Genetic toolkits for engineering Rhodococcus species with versatile applications. Biotechnol Adv 2021; 49:107748. [PMID: 33823269 DOI: 10.1016/j.biotechadv.2021.107748] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/31/2021] [Accepted: 03/31/2021] [Indexed: 02/09/2023]
Abstract
Rhodococcus spp. are a group of non-model gram-positive bacteria with diverse catabolic activities and strong adaptive capabilities, which enable their wide application in whole-cell biocatalysis, environmental bioremediation, and lignocellulosic biomass conversion. Compared with model microorganisms, the engineering of Rhodococcus is challenging because of the lack of universal molecular tools, high genome GC content (61% ~ 71%), and low transformation and recombination efficiencies. Nevertheless, because of the high interest in Rhodococcus species for bioproduction, various genetic elements and engineering tools have been recently developed for Rhodococcus spp., including R. opacus, R. jostii, R. ruber, and R. erythropolis, leading to the expansion of the genetic toolkits for Rhodococcus engineering. In this article, we provide a comprehensive review of the important developed genetic elements for Rhodococcus, including shuttle vectors, promoters, antibiotic markers, ribosome binding sites, and reporter genes. In addition, we also summarize gene transfer techniques and strategies to improve transformation efficiency, as well as random and precise genome editing tools available for Rhodococcus, including transposition, homologous recombination, recombineering, and CRISPR/Cas9. We conclude by discussing future trends in Rhodococcus engineering. We expect that more synthetic and systems biology tools (such as multiplex genome editing, dynamic regulation, and genome-scale metabolic models) will be adapted and optimized for Rhodococcus.
Collapse
Affiliation(s)
- Youxiang Liang
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China; Key Laboratory of Industrial Biocatalysis (Tsinghua University), the Ministry of Education, Beijing 100084, China
| | - Huimin Yu
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China; Key Laboratory of Industrial Biocatalysis (Tsinghua University), the Ministry of Education, Beijing 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China.
| |
Collapse
|
4
|
Single-Homology-Arm Linear DNA Recombination by the Nonhomologous End Joining Pathway as a Novel and Simple Gene Inactivation Method: a Proof-of-Concept Study in Dietzia sp. Strain DQ12-45-1b. Appl Environ Microbiol 2018; 84:AEM.00795-18. [PMID: 30030230 DOI: 10.1128/aem.00795-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/04/2018] [Indexed: 02/06/2023] Open
Abstract
Nonhomologous end joining (NHEJ) is critical for genome stability because of its roles in double-strand break repair. Ku and ligase D (LigD) are the crucial proteins in this process, and strains expressing Ku and LigD can cyclize linear DNA in vivo Here, we established a proof-of-concept single-homology-arm linear DNA recombination for gene inactivation or genome editing by which cyclization of linear DNA in vivo by NHEJ could be used to generate nonreplicable circular DNA and could allow allelic exchanges between the circular DNA and the chromosome. We achieved this approach in Dietzia sp. strain DQ12-45-1b, which expresses Ku and LigD homologs and presents NHEJ activity. By transforming the strain with a linear DNA single homolog to the sequence in the chromosome, we mutated the genome. This method did not require the screening of suitable plasmids and was easy and time-effective. Bioinformatic analysis showed that more than 20% of prokaryotic organisms contain Ku and LigD, suggesting the wide distribution of NHEJ activities. Moreover, an Escherichia coli strain also showed NHEJ activity when the Ku and LigD of Dietzia sp. DQ12-45-1b were introduced and expressed in it. Therefore, this method may be a widely applicable genome editing tool for diverse prokaryotic organisms, especially for nonmodel microorganisms.IMPORTANCE Many nonmodel Gram-positive bacteria lack efficient genetic manipulation systems, but they express genes encoding Ku and LigD. The NHEJ pathway in Dietzia sp. DQ12-45-1b was evaluated and was used to successfully knock out 11 genes in the genome. Since bioinformatic studies revealed that the putative genes encoding Ku and LigD ubiquitously exist in phylogenetically diverse bacteria and archaea, the single-homology-arm linear DNA recombination by the NHEJ pathway could be a potentially applicable genetic manipulation method for diverse nonmodel prokaryotic organisms.
Collapse
|
5
|
Luo J, Jiang F, Fang W, Lu Q. Optimization of bioconversion conditions for vitamin D3 to 25-hydroxyvitamin D using Pseudonocardia autotrophica CGMCC5098. BIOCATAL BIOTRANSFOR 2016. [DOI: 10.1080/10242422.2016.1268130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Jinqi Luo
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Fang Jiang
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Weizhen Fang
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China
| | - Qun Lu
- School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, China
| |
Collapse
|
6
|
Biodegradation of the organic disulfide 4,4'-dithiodibutyric acid by Rhodococcus spp. Appl Environ Microbiol 2015; 81:8294-306. [PMID: 26407888 DOI: 10.1128/aem.02059-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 09/17/2015] [Indexed: 02/07/2023] Open
Abstract
Four Rhodococcus spp. exhibited the ability to use 4,4'-dithiodibutyric acid (DTDB) as a sole carbon source for growth. The most important step for the production of a novel polythioester (PTE) using DTDB as a precursor substrate is the initial cleavage of DTDB. Thus, identification of the enzyme responsible for this step was mandatory. Because Rhodococcus erythropolis strain MI2 serves as a model organism for elucidation of the biodegradation of DTDB, it was used to identify the genes encoding the enzymes involved in DTDB utilization. To identify these genes, transposon mutagenesis of R. erythropolis MI2 was carried out using transposon pTNR-TA. Among 3,261 mutants screened, 8 showed no growth with DTDB as the sole carbon source. In five mutants, the insertion locus was mapped either within a gene coding for a polysaccharide deacetyltransferase, a putative ATPase, or an acetyl coenzyme A transferase, 1 bp upstream of a gene coding for a putative methylase, or 176 bp downstream of a gene coding for a putative kinase. In another mutant, the insertion was localized between genes encoding a putative transcriptional regulator of the TetR family (noxR) and an NADH:flavin oxidoreductase (nox). Moreover, in two other mutants, the insertion loci were mapped within a gene encoding a hypothetical protein in the vicinity of noxR and nox. The interruption mutant generated, R. erythropolis MI2 noxΩtsr, was unable to grow with DTDB as the sole carbon source. Subsequently, nox was overexpressed and purified, and its activity with DTDB was measured. The specific enzyme activity of Nox amounted to 1.2 ± 0.15 U/mg. Therefore, we propose that Nox is responsible for the initial cleavage of DTDB into 2 molecules of 4-mercaptobutyric acid (4MB).
Collapse
|
7
|
Rhodococcus prokaryotic ubiquitin-like protein (Pup) is degraded by deaminase of pup (Dop). Biosci Biotechnol Biochem 2012; 76:1959-66. [PMID: 23047115 DOI: 10.1271/bbb.120458] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Prokaryotic ubiquitin-like protein (Pup) is a functional analog of ubiquitin. Post-translationally modified pupylated proteins are selectively degraded by a proteasome-dependent proteolytic system. Deaminase of Pup (Dop) activates Pup by deaminating the C-terminal from glutamine to glutamate, and subsequently activated Pup is conjugated to target proteins by proteasome accessory factor A. Dop is also involved in the removal of Pup from pupylated proteins. Deconjugated free Pup is capable of religating to target proteins. Although the pupylation system is well studied in Mycobacterium, little is known about it in other actinomycetes. Both Rhodococcus and Mycobacterium Dop remove Pup from pupylated proteins, but in these two bacteria, no accumulation of deconjugated free Pup from Rhodococcus is observed. Analysis of a model pupylated protein revealed that Rhodococcus Pup is degraded at multiple sites by Dop. The endopeptidase activity of Dop can be detected using a fluorogenic substrate in conjunction with aminopeptidase. Moreover, the enzymatic activity of the model enzyme increases when Pup is deconjugated. These results suggest that depupylated Rhodococcus Pup is not recycled for religation with target proteins, and that Pup not only functions as a degradation signal, but also regulates the enzymatic activity of target proteins by conjugation and deconjugation to them.
Collapse
|
8
|
Kagawa Y, Mitani Y, Yun HY, Nakashima N, Tamura N, Tamura T. Identification of a methanol-inducible promoter from Rhodococcus erythropolis PR4 and its use as an expression vector. J Biosci Bioeng 2012; 113:596-603. [DOI: 10.1016/j.jbiosc.2011.12.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 12/26/2011] [Accepted: 12/27/2011] [Indexed: 11/26/2022]
|
9
|
Permeabilization induced by lipid II-targeting lantibiotic nisin and its effect on the bioconversion of vitamin D3 to 25-hydroxyvitamin D3 by Rhodococcus erythropolis. Biochem Biophys Res Commun 2011; 405:393-8. [PMID: 21237135 DOI: 10.1016/j.bbrc.2011.01.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
Abstract
Vitamin D3 (VD3) is a fat-soluble prohormone in mammals. VD3 is inert and must be activated by hydroxylation at the C-25 and C-1α positions to exert its biological activity. We recently accomplished the bioconversion of VD3 to 25(OH)VD3 with a recombinant strain of Rhodococcus erythropolis and found that the permeability of VD3 into the cytoplasm may be the rate-limiting step of 25(OH)VD3 production (Sallam et al., 2010). When the cells were treated with the lipid II-targeting lantibiotic nisin, the permeability of green chemiluminescent cyclodextrin (GCCD), which is used as a model substrate instead of VD3-partially methylated-β-cyclodextrin (PMCD) complex, was drastically induced. Nisin also induced VD3 hydroxylation, and the rate was correlated with the expression levels of Vdh and its redox partner proteins. In the bioconversion reaction, the stability of the redox partner proteins and the additional NADH-regenerating system are crucial for VD3 hydroxylation. The degradation rate of the [2Fe-2S] cluster of ferredoxin ThcC from R. erythropolis NI86/21 is faster than that of AciB from Acinetobacter sp. OC4. Therefore, the nisin-treated R. erythropolis cells coexpressing Vdh and AciBC (1176.5 μg) exhibited much greater 25(OH)VD3 production than the cells coexpressing Vdh and ThcCD (431.7 μg) after four consecutive 16 h reactions. These results suggest that nisin forms nisin-lipid II pore complexes in the Rhodococcus membrane that increase the accessibility of VD3-PMCD complexes to the inside of the cells. Furthermore, nisin-treated Rhodococcus cells can be utilized for the bioconversion of other fat-soluble chemicals.
Collapse
|
10
|
A robust system for production of minicircle DNA vectors. Nat Biotechnol 2010; 28:1287-9. [PMID: 21102455 PMCID: PMC4144359 DOI: 10.1038/nbt.1708] [Citation(s) in RCA: 241] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 10/15/2010] [Indexed: 12/02/2022]
Abstract
Minicircle DNA vectors consisting of a circular expression cassette devoid of the bacterial plasmid DNA backbone provides several advantages including sustained transgene expression in quiescent cells/tissues. Their use has been limited by labor-intensive production. We report on a strategy for making multiple genetic modifications in E.coli to construct a producer strain that stably expresses a set of inducible minicircle-assembly enzymes, the øC31-integrase and I-SceI homing-endonuclease. This bacterial strain is capable of producing highly purified minicircle yields in the same time frame as routine plasmid DNA. It is now feasible for minicircle DNA vectors to replace routine plasmids in mammalian transgene expression studies.
Collapse
|
11
|
Fanget NVJ, Foley S. Starvation/stationary-phase survival of Rhodococcus erythropolis SQ1: a physiological and genetic analysis. Arch Microbiol 2010; 193:1-13. [DOI: 10.1007/s00203-010-0638-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2010] [Revised: 09/12/2010] [Accepted: 09/30/2010] [Indexed: 11/24/2022]
|