Systems Metabolic Engineering of Industrial Microorganisms

A special issue of Microorganisms (ISSN 2076-2607). This special issue belongs to the section "Microbial Biotechnology".

Deadline for manuscript submissions: closed (31 December 2022) | Viewed by 41813

Special Issue Editors

Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
Interests: engineering biology; industrial biotechnology; C1 bioconversion; genome editing; CRISPR
School of Biotechnology, Jiangnan University, Wuxi 214122, China
Interests: metabolic engineering; synthetic biology; living cell imaging; industrial microorganism

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Guest Editor
College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, China
Interests: metabolic engineering; synthetic biology; oleaginous yeast; Yarrowia lipolytica; oleochemicals; terpenoids
Special Issues, Collections and Topics in MDPI journals
Department of Biology and Biological Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden
Interests: engineering biology; systems biology; microbiome; biomedical data science; multi-omics integration

Special Issue Information

Dear Colleagues,

Industrial biomanufacturing that converts renewable resources into chemicals, materials, fuels, foods, medicines, etc. is an important low-carbon manufacturing technology that holds promise for addressing global concerns over limited fossil resources and environmental problems. Microorganisms are the key biocatalysts of biomanufacturing. However, it is still challenging to develop microorganisms that meet the requirements of industrialization and commercialization, such as high production level (titer, yield, and productivity) and stable performance in scale-up fermentation. Metabolic engineering at the systems level enables the development of industrial microorganisms but also requires efficient tools for genome editing and gene regulation and diverse components with specific functions like catalysis and transport. The Special Issue entitled "Systems Metabolic Engineering of Industrial Microorganisms" aims to present recent research on any aspect of engineering microorganisms for biomanufacturing and biorefinery. Its focal points include, but are not limited to, the following:

  • Development of enabling technologies for systems metabolic engineering, such as genome editing, gene regulation, metabolic modeling, omics technologies, etc.
  • Engineering microorganisms or synthetic microbial consortia for the bioproduction of chemicals, materials, fuels, foods, medicines, etc.
  • Biorefinery of renewable resources such as lignocellulose, C1 feedstocks, low-grade biomass, etc.

Reviews, original research articles, and communications are welcome.

Dr. Yu Wang
Dr. Xueqin Lv
Dr. Xiao-Jun Ji
Dr. Boyang Ji
Guest Editors

Manuscript Submission Information

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Published Papers (14 papers)

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Editorial

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3 pages, 210 KiB  
Editorial
Systems Metabolic Engineering of Industrial Microorganisms
by Xueqin Lv, Yu Wang, Boyang Ji and Xiao-Jun Ji
Microorganisms 2023, 11(4), 926; https://doi.org/10.3390/microorganisms11040926 - 3 Apr 2023
Viewed by 1956
Abstract
The green and sustainable production of chemicals, materials, fuels, food, and pharmaceuticals has become a key solution to the global energy and environmental crisis [...] Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)

Research

Jump to: Editorial, Review

20 pages, 2811 KiB  
Article
Genetic Engineering of Agrobacterium Increases Curdlan Production through Increased Expression of the crdASC Genes
by Matthew McIntosh
Microorganisms 2024, 12(1), 55; https://doi.org/10.3390/microorganisms12010055 - 28 Dec 2023
Viewed by 1224
Abstract
Curdlan is a water-insoluble polymer that has structure and gelling properties that are useful in a wide variety of applications such as in medicine, cosmetics, packaging and the food and building industries. The capacity to produce curdlan has been detected in certain soil-dwelling [...] Read more.
Curdlan is a water-insoluble polymer that has structure and gelling properties that are useful in a wide variety of applications such as in medicine, cosmetics, packaging and the food and building industries. The capacity to produce curdlan has been detected in certain soil-dwelling bacteria of various phyla, although the role of curdlan in their survival remains unclear. One of the major limitations of the extensive use of curdlan in industry is the high cost of production during fermentation, partly because production involves specific nutritional requirements such as nitrogen limitation. Engineering of the industrially relevant curdlan-producing strain Agrobacterium sp. ATTC31749 is a promising approach that could decrease the cost of production. Here, during investigations on curdlan production, it was found that curdlan was deposited as a capsule. Curiously, only a part of the bacterial population produced a curdlan capsule. This heterogeneous distribution appeared to be due to the activity of Pcrd, the native promoter responsible for the expression of the crdASC biosynthetic gene cluster. To improve curdlan production, Pcrd was replaced by a promoter (PphaP) from another Alphaproteobacterium, Rhodobacter sphaeroides. Compared to Pcrd, PphaP was stronger and only mildly affected by nitrogen levels. Consequently, PphaP dramatically boosted crdASC gene expression and curdlan production. Importantly, the genetic modification overrode the strict nitrogen depletion regulation that presents a hindrance for maximal curdlan production and from nitrogen rich, complex media, demonstrating excellent commercial potential for achieving high yields using cheap substrates under relaxed fermentation conditions. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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15 pages, 2962 KiB  
Article
Metabolic Engineering of Escherichia coli for High-Level Production of (R)-Acetoin from Low-Cost Raw Materials
by Mengxue Diao, Xianrui Chen, Jing Li, Ya’nan Shi, Bo Yu, Zhilin Ma, Jianxiu Li and Nengzhong Xie
Microorganisms 2023, 11(1), 203; https://doi.org/10.3390/microorganisms11010203 - 13 Jan 2023
Cited by 1 | Viewed by 2992
Abstract
Acetoin is an important four-carbon platform chemical with versatile applications. Optically pure (R)-acetoin is more valuable than the racemate as it can be applied in the asymmetric synthesis of optically active α-hydroxy ketone derivatives, pharmaceuticals, and liquid crystal composites. As a [...] Read more.
Acetoin is an important four-carbon platform chemical with versatile applications. Optically pure (R)-acetoin is more valuable than the racemate as it can be applied in the asymmetric synthesis of optically active α-hydroxy ketone derivatives, pharmaceuticals, and liquid crystal composites. As a cytotoxic solvent, acetoin at high concentrations severely limits culture performance and impedes the acetoin yield of cell factories. In this study, putative genes that may improve the resistance to acetoin for Escherichia coli were screened. To obtain a high-producing strain, the identified acetoin-resistance gene was overexpressed, and the synthetic pathway of (R)-acetoin was strengthened by optimizing the copy number of the key genes. The engineered E. coli strain GXASR-49RSF produced 81.62 g/L (R)-acetoin with an enantiomeric purity of 96.5% in the fed-batch fermentation using non-food raw materials in a 3-L fermenter. Combining the systematic approach developed in this study with the use of low-cost feedstock showed great potential for (R)-acetoin production via this cost-effective biotechnological process. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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14 pages, 2765 KiB  
Article
ecBSU1: A Genome-Scale Enzyme-Constrained Model of Bacillus subtilis Based on the ECMpy Workflow
by Ke Wu, Zhitao Mao, Yufeng Mao, Jinhui Niu, Jingyi Cai, Qianqian Yuan, Lili Yun, Xiaoping Liao, Zhiwen Wang and Hongwu Ma
Microorganisms 2023, 11(1), 178; https://doi.org/10.3390/microorganisms11010178 - 11 Jan 2023
Cited by 12 | Viewed by 2736
Abstract
Genome-scale metabolic models (GEMs) play an important role in the phenotype prediction of microorganisms, and their accuracy can be further improved by integrating other types of biological data such as enzyme concentrations and kinetic coefficients. Enzyme-constrained models (ecModels) have been constructed for several [...] Read more.
Genome-scale metabolic models (GEMs) play an important role in the phenotype prediction of microorganisms, and their accuracy can be further improved by integrating other types of biological data such as enzyme concentrations and kinetic coefficients. Enzyme-constrained models (ecModels) have been constructed for several species and were successfully applied to increase the production of commodity chemicals. However, there was still no genome-scale ecModel for the important model organism Bacillus subtilis prior to this study. Here, we integrated enzyme kinetic and proteomic data to construct the first genome-scale ecModel of B. subtilis (ecBSU1) using the ECMpy workflow. We first used ecBSU1 to simulate overflow metabolism and explore the trade-off between biomass yield and enzyme usage efficiency. Next, we simulated the growth rate on eight previously published substrates and found that the simulation results of ecBSU1 were in good agreement with the literature. Finally, we identified target genes that enhance the yield of commodity chemicals using ecBSU1, most of which were consistent with the experimental data, and some of which may be potential novel targets for metabolic engineering. This work demonstrates that the integration of enzymatic constraints is an effective method to improve the performance of GEMs. The ecModel can predict overflow metabolism more precisely and can be used for the identification of target genes to guide the rational design of microbial cell factories. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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14 pages, 3172 KiB  
Article
The Influence of Hydrodynamic Conditions in a Laboratory-Scale Bioreactor on Pseudomonas aeruginosa Metabolite Production
by Maciej Konopacki, Joanna Jabłońska, Kamila Dubrowska, Adrian Augustyniak, Bartłomiej Grygorcewicz, Marta Gliźniewicz, Emil Wróblewski, Marian Kordas, Barbara Dołęgowska and Rafał Rakoczy
Microorganisms 2023, 11(1), 88; https://doi.org/10.3390/microorganisms11010088 - 29 Dec 2022
Cited by 1 | Viewed by 3048
Abstract
Hydrodynamic conditions are critical in bioprocessing because they influence oxygen availability for cultured cells. Processes in typical laboratory bioreactors need optimization of these conditions using mixing and aeration control to obtain high production of the desired bioproduct. It could be done by experiments [...] Read more.
Hydrodynamic conditions are critical in bioprocessing because they influence oxygen availability for cultured cells. Processes in typical laboratory bioreactors need optimization of these conditions using mixing and aeration control to obtain high production of the desired bioproduct. It could be done by experiments supported by computational fluid dynamics (CFD) modeling. In this work, we characterized parameters such as mixing time, power consumption and mass transfer in a 2 L bioreactor. Based on the obtained results, we chose a set of nine process parameters to test the hydrodynamic impact on a selected bioprocess (mixing in the range of 0–160 rpm and aeration in the range of 0–250 ccm). Therefore, we conducted experiments with P. aeruginosa culture and assessed how various hydrodynamic conditions influenced biomass, pyocyanin and rhamnolipid production. We found that a relatively high mass transfer of oxygen (kLa = 0.0013 s−1) connected with intensive mixing (160 rpm) leads to the highest output of pyocyanin production. In contrast, rhamnolipid production reached maximal efficiency under moderate oxygen mass transfer (kLa = 0.0005 s−1) and less intense mixing (in the range of 0–60 rpm). The results indicate that manipulating hydrodynamics inside the bioreactor allows control of the process and may lead to a change in the metabolites produced by bacterial cells. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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16 pages, 2043 KiB  
Article
Mechanisms of BPA Degradation and Toxicity Resistance in Rhodococcus equi
by Kejian Tian, Yue Yu, Qing Qiu, Xuejian Sun, Fanxing Meng, Yuanping Bi, Jinming Gu, Yibing Wang, Fenglin Zhang and Hongliang Huo
Microorganisms 2023, 11(1), 67; https://doi.org/10.3390/microorganisms11010067 - 26 Dec 2022
Cited by 11 | Viewed by 2670
Abstract
Bisphenol A (BPA) pollution poses an increasingly serious problem. BPA has been detected in a variety of environmental media and human tissues. Microbial degradation is an effective method of environmental BPA remediation. However, BPA is also biotoxic to microorganisms. In this study, Rhodococcus [...] Read more.
Bisphenol A (BPA) pollution poses an increasingly serious problem. BPA has been detected in a variety of environmental media and human tissues. Microbial degradation is an effective method of environmental BPA remediation. However, BPA is also biotoxic to microorganisms. In this study, Rhodococcus equi DSSKP-R-001 (R-001) was used to degrade BPA, and the effects of BPA on the growth metabolism, gene expression patterns, and toxicity-resistance mechanisms of Rhodococcus equi were analyzed. The results showed that R-001 degraded 51.2% of 5 mg/L BPA and that 40 mg/L BPA was the maximum BPA concentration tolerated by strain R-001. Cytochrome P450 monooxygenase and multicopper oxidases played key roles in BPA degradation. However, BPA was toxic to strain R-001, exhibiting nonlinear inhibitory effects on the growth and metabolism of this bacterium. R-001 bacterial biomass, total protein content, and ATP content exhibited V-shaped trends as BPA concentration increased. The toxic effects of BPA included the downregulation of R-001 genes related to glycolysis/gluconeogenesis, pentose phosphate metabolism, and glyoxylate and dicarboxylate metabolism. Genes involved in aspects of the BPA-resistance response, such as base excision repair, osmoprotectant transport, iron-complex transport, and some energy metabolisms, were upregulated to mitigate the loss of energy associated with BPA exposure. This study helped to clarify the bacterial mechanisms involved in BPA biodegradation and toxicity resistance, and our results provide a theoretical basis for the application of strain R-001 in BPA pollution treatments. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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16 pages, 1450 KiB  
Article
Safety Evaluation of Bacillus subtilis IDCC1101, Newly Isolated from Cheonggukjang, for Industrial Applications
by Su-Hyeon Kim, Gashaw Assefa Yehuala, Won Yeong Bang, Jungwoo Yang, Young Hoon Jung and Mi-Kyung Park
Microorganisms 2022, 10(12), 2494; https://doi.org/10.3390/microorganisms10122494 - 16 Dec 2022
Cited by 7 | Viewed by 3648
Abstract
The present study aimed to evaluate the safety of Bacillus subtilis (BS) IDCC1101, newly isolated from Cheonggukjang in Korea. Genome sequencing of BS IDCC1101 was performed to investigate the presence of secondary metabolites, virulence, antibiotic resistance, and mobile elements. Its phenotypic safety analyses [...] Read more.
The present study aimed to evaluate the safety of Bacillus subtilis (BS) IDCC1101, newly isolated from Cheonggukjang in Korea. Genome sequencing of BS IDCC1101 was performed to investigate the presence of secondary metabolites, virulence, antibiotic resistance, and mobile elements. Its phenotypic safety analyses included antibiotic susceptibility, enzyme activity, carbohydrate utilization, production of biogenic amines (BAs) and D-/L-lactate, hemolytic activity, and toxicities in HaCaT cells and rats. The genome of BS IDCC1101 consisted of 4,118,950 bp with 3077 functional genes. Among them, antimicrobial and antifungal secondary metabolites were found, such as fengycin, bacillibactin, and bacilysin. Antibiotic resistance and virulence genes did not exhibit transferability since they did not overlap with mobile elements in the genome. BS IDCC1101 was susceptible to almost all antibiotics suggested for assessment of BS’s antibiotic susceptibility by EFSA guidelines, except for streptomycin. BS IDCC1101 showed the utilization of a wide range of 27 carbohydrates, as well as enzyme activities such as alkaline phosphatase, esterase, esterase lipase, naphthol-AS-BI-phosphohydrolase, α-galactosidase, β-galactosidase, α-glucosidase, and β-glucosidase activities. Additionally, BS IDCC1101 did not exhibit the production of D-/L-lactate and hemolytic activities. Its toxicity in HaCaT cells and rats was also not detected. Thus, these genotypic and phenotypic findings indicate that BS IDCC1101 can be safely used for industrial applications. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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13 pages, 1694 KiB  
Article
Production of Mannosylerythritol Lipids Using Oils from Oleaginous Microalgae: Two Sequential Microorganism Culture Approach
by Miguel Figueiredo Nascimento, Tiago Coelho, Alberto Reis, Luísa Gouveia, Nuno Torres Faria and Frederico Castelo Ferreira
Microorganisms 2022, 10(12), 2390; https://doi.org/10.3390/microorganisms10122390 - 2 Dec 2022
Cited by 6 | Viewed by 2025
Abstract
Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a wide range of potential applications. However, most of the studies focusing on MELs high titre production have been relying in the use of vegetable oils with impact on the sustainability and process [...] Read more.
Mannosylerythritol lipids (MELs) are biosurfactants with excellent biochemical properties and a wide range of potential applications. However, most of the studies focusing on MELs high titre production have been relying in the use of vegetable oils with impact on the sustainability and process economy. Herein, we report for the first time MELs production using oils produced from microalgae. The bio-oil was extracted from Neochloris oleoabundans and evaluated for their use as sole carbon source or in a co-substrate strategy, using as an additional carbon source D-glucose, on Moesziomyces spp. cultures to support cell growth and induce the production of MELs. Both Moesziomyces antarcticus and M. aphidis were able to grow and produce MELs using algae-derived bio-oils as a carbon source. Using a medium containing as carbon sources 40 g/L of D-glucose and 20 g/L of bio-oils, Moesziomyces antarcticus and M. aphidis produced 12.47 ± 0.28 and 5.72 ± 2.32 g/L of MELs, respectively. Interestingly, there are no significant differences in productivity when using oils from microalgae or vegetable oils as carbon sources. The MELs productivities achieved were 1.78 ± 0.04 and 1.99 ± 0.12 g/L/day, respectively, for M. antarcticus fed with algae-derived or vegetable oils. These results open new perspectives for the production of MELs in systems combining different microorganisms. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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16 pages, 4546 KiB  
Article
New Technique for Enhancing Residual Oil Recovery from Low-Permeability Reservoirs: The Cooperation of Petroleum Hydrocarbon-Degrading Bacteria and SiO2 Nanoparticles
by Kai Cui, Hailan Li, Ping Chen, Yong Li, Wenxue Jiang and Kun Guo
Microorganisms 2022, 10(11), 2104; https://doi.org/10.3390/microorganisms10112104 - 24 Oct 2022
Cited by 2 | Viewed by 1669
Abstract
Residual crude oil production from low-permeability reservoirs has become a huge challenge because conventional recovery techniques are inefficient. Nanofluids as a new type of oil-displacement agent have become a hot topic in recent years to enhance oil recovery (EOR) in reservoirs. However, the [...] Read more.
Residual crude oil production from low-permeability reservoirs has become a huge challenge because conventional recovery techniques are inefficient. Nanofluids as a new type of oil-displacement agent have become a hot topic in recent years to enhance oil recovery (EOR) in reservoirs. However, the imperfection of agglomeration, dissolution, and instability of nanofluids in reservoir environments limit their ability to drive oil. Here, a novel “microbial-nanofluid” composed of petroleum hydrocarbon-degrading bacteria (PHDB, namely Bacillus cereus) and SiO2 nanoparticles was proposed as a potential new technology for enhancing residual oil recovery. The micromodel displacement test results showed that the optimum composite concentration of “microbial-nanofluids” were PHDB (7.0%, v/v) and SiO2 nanoparticles (100 mg/L), and the residual oil recovery was increased by 30.1% compared with waterflooding (68.8%). Moreover, the morphological characteristics of residual oil mobilization after “microbial-nanofluid” flooding were mainly small and dispersed oil droplets in the excessive areas, and the dead-end areas were almost clean with mobilization. Furthermore, the cooperation mechanism of four kinds of “microbial-nanofluids” to enhance the residual oil recovery in low-permeability reservoirs was preliminarily clarified, namely the co-emulsification of oil, working together to unclog oil clog, microbial-nanofluid self-assembly, and structural disjoining pressure. This study demonstrated that PHDB-SiO2 nanoparticle composite flooding technology provided a significant potential for the EOR from low-permeability reservoirs. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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12 pages, 1431 KiB  
Article
Engineering Cell Polarization Improves Protein Production in Saccharomyces cerevisiae
by Shuo Yang, Junfeng Shen, Jiliang Deng, Hongxing Li, Jianzhi Zhao, Hongting Tang and Xiaoming Bao
Microorganisms 2022, 10(10), 2005; https://doi.org/10.3390/microorganisms10102005 - 11 Oct 2022
Cited by 5 | Viewed by 2010
Abstract
Saccharomyces cerevisiae has been widely used as a microbial cell factory to produce recombinant proteins. Therefore, enhancing the protein production efficiency of yeast cell factories to expand the market demand for protein products is necessary. Recombinant proteins are often retained in the secretory [...] Read more.
Saccharomyces cerevisiae has been widely used as a microbial cell factory to produce recombinant proteins. Therefore, enhancing the protein production efficiency of yeast cell factories to expand the market demand for protein products is necessary. Recombinant proteins are often retained in the secretory pathway because of the limited protein transport performed by vesicle trafficking. Cell polarization describes the asymmetric organization of the plasma membrane cytoskeleton and organelles and tightly regulates vesicle trafficking for protein transport. Engineering vesicle trafficking has broadly been studied by the overexpression or deletion of key genes involved but not by modifying cell polarization. Here, we used α-amylase as a reporter protein, and its secretion and surface-display were first improved by promoter optimization. To study the effect of engineering cell polarization on protein production, fourteen genes related to cell polarization were overexpressed. BUD1, CDC42, AXL1, and BUD10 overexpression increased the activity of surface-displayed α-amylase, and BUD1, BUD3, BUD4, BUD7, and BUD10 overexpression enhanced secreted α-amylase activity. Furthermore, BUD1 overexpression increased the surface-displayed and secreted α-amylase expression by 56% and 49%, respectively. We also observed that the combinatorial modification and regulation of gene expression improved α-amylase production in a dose-dependent manner. BUD1 and CDC42 co-overexpression increased the α-amylase surface display by 100%, and two genomic copies of BUD1 improved α-amylase secretion by 92%. Furthermore, these modifications were used to improve the surface display and secretion of the recombinant β-glucosidase protein. Our study affords a novel insight for improving the surface display and secretion of recombinant proteins. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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17 pages, 4556 KiB  
Article
Combinatorial Metabolic Engineering and Enzymatic Catalysis Enable Efficient Production of Colanic Acid
by Suwei Li, Xianhao Xu, Xueqin Lv, Yanfeng Liu, Jianghua Li, Guocheng Du and Long Liu
Microorganisms 2022, 10(5), 877; https://doi.org/10.3390/microorganisms10050877 - 22 Apr 2022
Cited by 6 | Viewed by 2634
Abstract
Colanic acid can promote the lifespan of humans by regulating mitochondrial homeostasis, and it has widespread applications in the field of health. However, colanic acid is produced at a low temperature (20 °C) with low titer. Using Escherichia coli K-12 MG1655, we constructed [...] Read more.
Colanic acid can promote the lifespan of humans by regulating mitochondrial homeostasis, and it has widespread applications in the field of health. However, colanic acid is produced at a low temperature (20 °C) with low titer. Using Escherichia coli K-12 MG1655, we constructed the SRP-4 strain with high colanic acid production at 30 °C by enhancing the precursor supply and relieving the regulation of transcription for colanic acid synthesis genes by the RCS system. After media optimization, the colanic acid titer increased by 579.9-fold and reached 12.2 g/L. Subsequently, we successfully purified the colanic acid hydrolase and reduced the molecular weight of colanic acid (106.854 kDa), thereby eliminating the inhibition of high-molecular-weight colanic acid on strain growth. Finally, after adding the colanic acid hydrolase (4000 U/L), the colanic acid with low molecular weight reached 24.99 g/L in 3-L bioreactor, the highest titer reported so far. This high-producing strain of colanic acid will promote the application of low-molecular-weight colanic acid in the field of health. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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Review

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34 pages, 1785 KiB  
Review
Current Metabolic Engineering Strategies for Photosynthetic Bioproduction in Cyanobacteria
by Alessandro Satta, Lygie Esquirol and Birgitta E. Ebert
Microorganisms 2023, 11(2), 455; https://doi.org/10.3390/microorganisms11020455 - 11 Feb 2023
Cited by 10 | Viewed by 4043
Abstract
Cyanobacteria are photosynthetic microorganisms capable of using solar energy to convert CO2 and H2O into O2 and energy-rich organic compounds, thus enabling sustainable production of a wide range of bio-products. More and more strains of cyanobacteria are identified that [...] Read more.
Cyanobacteria are photosynthetic microorganisms capable of using solar energy to convert CO2 and H2O into O2 and energy-rich organic compounds, thus enabling sustainable production of a wide range of bio-products. More and more strains of cyanobacteria are identified that show great promise as cell platforms for the generation of bioproducts. However, strain development is still required to optimize their biosynthesis and increase titers for industrial applications. This review describes the most well-known, newest and most promising strains available to the community and gives an overview of current cyanobacterial biotechnology and the latest innovative strategies used for engineering cyanobacteria. We summarize advanced synthetic biology tools for modulating gene expression and their use in metabolic pathway engineering to increase the production of value-added compounds, such as terpenoids, fatty acids and sugars, to provide a go-to source for scientists starting research in cyanobacterial metabolic engineering. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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15 pages, 616 KiB  
Review
Metabolic Engineering of Bacillus subtilis for Riboflavin Production: A Review
by Yang Liu, Quan Zhang, Xiaoxiao Qi, Huipeng Gao, Meng Wang, Hao Guan and Bo Yu
Microorganisms 2023, 11(1), 164; https://doi.org/10.3390/microorganisms11010164 - 8 Jan 2023
Cited by 5 | Viewed by 4473
Abstract
Riboflavin (vitamin B2) is one of the essential vitamins that the human body needs to maintain normal metabolism. Its biosynthesis has become one of the successful models for gradual replacement of traditional chemical production routes. B. subtilis is characterized by its [...] Read more.
Riboflavin (vitamin B2) is one of the essential vitamins that the human body needs to maintain normal metabolism. Its biosynthesis has become one of the successful models for gradual replacement of traditional chemical production routes. B. subtilis is characterized by its short fermentation time and high yield, which shows a huge competitive advantage in microbial fermentation for production of riboflavin. This review summarized the advancements of regulation on riboflavin production as well as the synthesis of two precursors of ribulose-5-phosphate riboflavin (Ru5P) and guanosine 5′-triphosphate (GTP) in B. subtilis. The different strategies to improve production of riboflavin by metabolic engineering were also reviewed. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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15 pages, 2194 KiB  
Review
Closing the Gap between Bio-Based and Petroleum-Based Plastic through Bioengineering
by Dina Al-Khairy, Weiqi Fu, Amnah Salem Alzahmi, Jean-Claude Twizere, Shady A. Amin, Kourosh Salehi-Ashtiani and Alexandra Mystikou
Microorganisms 2022, 10(12), 2320; https://doi.org/10.3390/microorganisms10122320 - 23 Nov 2022
Cited by 12 | Viewed by 4870
Abstract
Bioplastics, which are plastic materials produced from renewable bio-based feedstocks, have been investigated for their potential as an attractive alternative to petroleum-based plastics. Despite the harmful effects of plastic accumulation in the environment, bioplastic production is still underdeveloped. Recent advances in strain development, [...] Read more.
Bioplastics, which are plastic materials produced from renewable bio-based feedstocks, have been investigated for their potential as an attractive alternative to petroleum-based plastics. Despite the harmful effects of plastic accumulation in the environment, bioplastic production is still underdeveloped. Recent advances in strain development, genome sequencing, and editing technologies have accelerated research efforts toward bioplastic production and helped to advance its goal of replacing conventional plastics. In this review, we highlight bioengineering approaches, new advancements, and related challenges in the bioproduction and biodegradation of plastics. We cover different types of polymers, including polylactic acid (PLA) and polyhydroxyalkanoates (PHAs and PHBs) produced by bacterial, microalgal, and plant species naturally as well as through genetic engineering. Moreover, we provide detailed information on pathways that produce PHAs and PHBs in bacteria. Lastly, we present the prospect of using large-scale genome engineering to enhance strains and develop microalgae as a sustainable production platform. Full article
(This article belongs to the Special Issue Systems Metabolic Engineering of Industrial Microorganisms)
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