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Liu J, Chen M, Gu S, Fan R, Zhao Z, Sun W, Yao Y, Li J, Tian C. Independent metabolism of oligosaccharides is the keystone of synchronous utilization of cellulose and hemicellulose in Myceliophthora. PNAS NEXUS 2024; 3:pgae053. [PMID: 38380057 PMCID: PMC10877092 DOI: 10.1093/pnasnexus/pgae053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 01/29/2024] [Indexed: 02/22/2024]
Abstract
The effective utilization of cellulose and hemicellulose, the main components of plant biomass, is a key technical obstacle that needs to be overcome for the economic viability of lignocellulosic biorefineries. Here, we firstly demonstrated that the thermophilic cellulolytic fungus Myceliophthora thermophila can simultaneously utilize cellulose and hemicellulose, as evidenced by the independent uptake and intracellular metabolism of cellodextrin and xylodextrin. When plant biomass serviced as carbon source, we detected the cellodextrin and xylodextrin both in cells and in the culture medium, as well as high enzyme activities related to extracellular oligosaccharide formation and intracellular oligosaccharide hydrolysis. Sugar consumption assay revealed that in contrast to inhibitory effect of glucose on xylose and cellodextrin/xylodextrin consumption in mixed-carbon media, cellodextrin and xylodextrin were synchronously utilized in this fungus. Transcriptomic analysis also indicated simultaneous induction of the genes involved in cellodextrin and xylodextrin metabolic pathway, suggesting carbon catabolite repression (CCR) is triggered by extracellular glucose and can be eliminated by the intracellular hydrolysis and metabolism of oligosaccharides. The xylodextrin transporter MtCDT-2 was observed to preferentially transport xylobiose and tolerate high cellobiose concentrations, which helps to bypass the inhibition of xylobiose uptake. Furthermore, the expression of cellulase and hemicellulase genes was independently induced by their corresponding inducers, which enabled this strain to synchronously utilize cellulose and hemicellulose. Taken together, the data presented herein will further elucidate the degradation of plant biomass by fungi, with implications for the development of consolidated bioprocessing-based lignocellulosic biorefinery.
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Affiliation(s)
- Jia Liu
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Meixin Chen
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Shuying Gu
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Rui Fan
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Zhen Zhao
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Wenliang Sun
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Yonghong Yao
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Jingen Li
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Chaoguang Tian
- Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
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Xue F, Zhao Z, Gu S, Chen M, Xu J, Luo X, Li J, Tian C. The transcriptional factor Clr-5 is involved in cellulose degradation through regulation of amino acid metabolism in Neurospora crassa. BMC Biotechnol 2023; 23:50. [PMID: 38031036 PMCID: PMC10687990 DOI: 10.1186/s12896-023-00823-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/23/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND Filamentous fungi are efficient degraders of plant biomass and the primary producers of commercial cellulolytic enzymes. While the transcriptional regulation mechanisms of cellulases have been continuously explored in lignocellulolytic fungi, the induction of cellulase production remains a complex multifactorial system, with several aspects still largely elusive. RESULTS In this study, we identified a Zn2Cys6 transcription factor, designated as Clr-5, which regulates the expression of cellulase genes by influencing amino acid metabolism in Neurospora crassa during growth on cellulose. The deletion of clr-5 caused a significant decrease in secreted protein and cellulolytic enzyme activity of N. crassa, which was partially alleviated by supplementing with yeast extract. Transcriptomic profiling revealed downregulation of not only the genes encoding main cellulases but also those related to nitrogen metabolism after disruption of Clr-5 under Avicel condition. Clr-5 played a crucial role in the utilization of multiple amino acids, especially leucine and histidine. When using leucine or histidine as the sole nitrogen source, the Δclr-5 mutant showed significant growth defects on both glucose and Avicel media. Comparative transcriptomic analysis revealed that the transcript levels of most genes encoding carbohydrate-active enzymes and those involved in the catabolism and uptake of histidine, branched-chain amino acids, and aromatic amino acids, were remarkably reduced in strain Δclr-5, compared with the wild-type N. crassa when grown in Avicel medium with leucine or histidine as the sole nitrogen source. These findings underscore the important role of amino acid metabolism in the regulation of cellulase production in N. crassa. Furthermore, the function of Clr-5 in regulating cellulose degradation is conserved among ascomycete fungi. CONCLUSIONS These findings regarding the novel transcription factor Clr-5 enhance our comprehension of the regulatory connections between amino acid metabolism and cellulase production, offering fresh prospects for the development of fungal cell factories dedicated to cellulolytic enzyme production in bio-refineries.
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Affiliation(s)
- Fanglei Xue
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, China
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Zhen Zhao
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Shuying Gu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Meixin Chen
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, China
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Jing Xu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Xuegang Luo
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, China
| | - Jingen Li
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.
| | - Chaoguang Tian
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.
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Li J, Wang Y, Yang K, Wang X, Wang Y, Zhang H, Huang H, Su X, Yao B, Luo H, Qin X. Development of an efficient protein expression system in the thermophilic fungus Myceliophthora thermophila. Microb Cell Fact 2023; 22:236. [PMID: 37974259 PMCID: PMC10652509 DOI: 10.1186/s12934-023-02245-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 11/05/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Thermophilic fungus Myceliophthora thermophila has been widely used in industrial applications due to its ability to produce various enzymes. However, the lack of an efficient protein expression system has limited its biotechnological applications. RESULTS In this study, using a laccase gene reporting system, we developed an efficient protein expression system in M. thermophila through the selection of strong constitutive promoters, 5'UTRs and signal peptides. The expression of the laccase was confirmed by enzyme activity assays. The results showed that the Mtpdc promoter (Ppdc) was able to drive high-level expression of the target protein in M. thermophila. Manipulation of the 5'UTR also has significant effects on protein expression and secretion. The best 5'UTR (NCA-7d) was identified. The transformant containing the laccase gene under the Mtpdc promoter, NCA-7d 5'UTR and its own signal peptide with the highest laccase activity (1708 U/L) was obtained. In addition, the expression system was stable and could be used for the production of various proteins, including homologous proteins like MtCbh-1, MtGh5-1, MtLPMO9B, and MtEpl1, as well as a glucoamylase from Trichoderma reesei. CONCLUSIONS An efficient protein expression system was established in M. thermophila for the production of various proteins. This study provides a valuable tool for protein production in M. thermophila and expands its potential for biotechnological applications.
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Affiliation(s)
- Jinyang Li
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Yidi Wang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Kun Yang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Xiaolu Wang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Yuan Wang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Honglian Zhang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Huoqing Huang
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Xiaoyun Su
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China.
| | - Xing Qin
- State Key Laboratory of Animal Nutrition and Feeding, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, 10093, China.
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Zhu Z, Zhang M, Liu D, Liu D, Sun T, Yang Y, Dong J, Zhai H, Sun W, Liu Q, Tian C. Development of the thermophilic fungus Myceliophthora thermophila into glucoamylase hyperproduction system via the metabolic engineering using improved AsCas12a variants. Microb Cell Fact 2023; 22:150. [PMID: 37568174 PMCID: PMC10416393 DOI: 10.1186/s12934-023-02149-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/13/2023] [Indexed: 08/13/2023] Open
Abstract
BACKGROUND Glucoamylase is an important enzyme for starch saccharification in the food and biofuel industries and mainly produced from mesophilic fungi such as Aspergillus and Rhizopus species. Enzymes produced from thermophilic fungi can save the fermentation energy and reduce costs as compared to the fermentation system using mesophiles. Thermophilic fungus Myceliophthora thermophila is industrially deployed fungus to produce enzymes and biobased chemicals from biomass during optimal growth at 45 °C. This study aimed to construct the M. thermophila platform for glucoamylase hyper-production by broadening genomic targeting range of the AsCas12a variants, identifying key candidate genes and strain engineering. RESULTS In this study, to increase the genome targeting range, we upgraded the CRISPR-Cas12a-mediated technique by engineering two AsCas12a variants carrying the mutations S542R/K607R and S542R/K548V/N552R. Using the engineered AsCas12a variants, we deleted identified key factors involved in the glucoamylase expression and secretion in M. thermophila, including Mtstk-12, Mtap3m, Mtdsc-1 and Mtsah-2. Deletion of four targets led to more than 1.87- and 1.85-fold higher levels of secretion and glucoamylases activity compared to wild-type strain MtWT. Transcript level of the major amylolytic genes showed significantly increased in deletion mutants. The glucoamylase hyper-production strain MtGM12 was generated from our previously strain MtYM6 via genetically engineering these targets Mtstk-12, Mtap3m, Mtdsc-1 and Mtsah-2 and overexpressing Mtamy1 and Mtpga3. Total secreted protein and activities of amylolytic enzymes in the MtGM12 were about 35.6-fold and 51.9‒55.5-fold higher than in MtWT. Transcriptional profiling analyses revealed that the amylolytic gene expression levels were significantly up-regulated in the MtGM12 than in MtWT. More interestingly, the MtGM12 showed predominantly short and highly bulging hyphae with proliferation of rough ER and abundant mitochondria, secretion vesicles and vacuoles when culturing on starch. CONCLUSIONS Our results showed that these AsCas12a variants worked well for gene deletions in M. thermophila. We successfully constructed the glucoamylase hyper-production strain of M. thermophila by the rational redesigning and engineering the transcriptional regulatory and secretion pathway. This targeted engineering strategy will be very helpful to improve industrial fungal strains and promote the morphology engineering for enhanced enzyme production.
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Affiliation(s)
- Zhijian Zhu
- Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, China
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Manyu Zhang
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Dandan Liu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Defei Liu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Tao Sun
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Yujing Yang
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Jiacheng Dong
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Huanhuan Zhai
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Wenliang Sun
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Qian Liu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.
| | - Chaoguang Tian
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.
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Huang Z, Hu T, Yang S, Tian X, Wu Z. Genetic responses to adding nitrates to improve hydrophilic yellow pigment in Monascus fermentation. Appl Microbiol Biotechnol 2023; 107:1341-1359. [PMID: 36705673 DOI: 10.1007/s00253-023-12392-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/12/2023] [Accepted: 01/15/2023] [Indexed: 01/28/2023]
Abstract
Nitrates can stimulate the biosynthesis of hydrophilic yellow pigments (HYPs) in Monascus ruber CGMCC 10910. To explore the molecular mechanisms whereby nitrates (NaNO3 and NH4NO3) regulate HYP production, an integrated transcriptomic and proteomic analysis was conducted in this study. Nitrate addition led to an approximately 75% higher HYP production compared with the untreated group, especially compounds Y3 and Y4. Comparative transcriptomic analysis found that mpigsA, H, K, L, and P genes involved in yellow pigment biosynthesis were significantly upregulated. In addition, pigment biosynthesis-related (carbon catabolism, amino acid metabolism, polyketide synthesis, and fatty acid metabolism) genes were upregulated to provide precursors and energy for HYP biosynthesis and cell growth. Secretion-related (cytomembrane ergosterol biosynthetic, and transport) pathways were also noticeably regulated to accelerate transmembrane transport of HYPs. Meanwhile, proteomic analysis showed that nitrates improved the protein expression of hybrid polyketide synthase-nonribosomal peptide synthetase, oxidoreductase, glucoamylase, endo-1,4-beta-xylanase, O-acetylhomoserine, and isocitrate lyase to enhance HYP production. These findings demonstrated the regulatory mechanism of nitrates for enhancing HYP production in Monascus. KEY POINTS: • Nitrates stimulated the biosynthesis of Monascus hydrophilic yellow pigments (HYPs) • Nitrates affected transcriptional level of pigment biosynthesis- and transport genes • Increased expression of hybrid PKS-NRPS and transporters promoted production of HYPs.
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Affiliation(s)
- Zhenfeng Huang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Tingting Hu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China.,Pan Asia (Jiangmen) Institute of Biological Engineering and Health, Jiangmen, 529080, People's Republic of China
| | - Shanzhong Yang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Xiaofei Tian
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China.,Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, Guangzhou, 510006, China
| | - Zhenqiang Wu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China.
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Liu D, Zhang Y, Li J, Sun W, Yao Y, Tian C. The Weimberg pathway: an alternative for Myceliophthora thermophila to utilize D-xylose. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:13. [PMID: 36691040 PMCID: PMC9869559 DOI: 10.1186/s13068-023-02266-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/13/2023] [Indexed: 01/24/2023]
Abstract
BACKGROUND With D-xylose being the second most abundant sugar in nature, its conversion into products could significantly improve biomass-based process economy. There are two well-studied phosphorylative pathways for D-xylose metabolism. One is isomerase pathway mainly found in bacteria, and the other one is oxo-reductive pathway that always exists in fungi. Except for these two pathways, there are also non-phosphorylative pathways named xylose oxidative pathways and they have several advantages over traditional phosphorylative pathways. In Myceliophthora thermophila, D-xylose can be metabolized through oxo-reductive pathway after plant biomass degradation. The survey of non-phosphorylative pathways in this filamentous fungus will offer a potential way for carbon-efficient production of fuels and chemicals using D-xylose. RESULTS In this study, an alternative for utilization of D-xylose, the non-phosphorylative Weimberg pathway was established in M. thermophila. Growth on D-xylose of strains whose D-xylose reductase gene was disrupted, was restored after overexpression of the entire Weimberg pathway. During the construction, a native D-xylose dehydrogenase with highest activity in M. thermophila was discovered. Here, M. thermophila was also engineered to produce 1,2,4-butanetriol using D-xylose through non-phosphorylative pathway. Afterwards, transcriptome analysis revealed that the D-xylose dehydrogenase gene was obviously upregulated after deletion of D-xylose reductase gene when cultured in a D-xylose medium. Besides, genes involved in growth were enriched in strains containing the Weimberg pathway. CONCLUSIONS The Weimberg pathway was established in M. thermophila to support its growth with D-xylose being the sole carbon source. Besides, M. thermophila was engineered to produce 1,2,4-butanetriol using D-xylose through non-phosphorylative pathway. To our knowledge, this is the first report of non-phosphorylative pathway recombinant in filamentous fungi, which shows great potential to convert D-xylose to valuable chemicals.
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Affiliation(s)
- Defei Liu
- grid.9227.e0000000119573309Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China ,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308 China
| | - Yongli Zhang
- grid.9227.e0000000119573309Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China ,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308 China
| | - Jingen Li
- grid.9227.e0000000119573309Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China ,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308 China
| | - Wenliang Sun
- grid.9227.e0000000119573309Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China ,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308 China
| | - Yonghong Yao
- grid.9227.e0000000119573309Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China ,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308 China
| | - Chaoguang Tian
- grid.9227.e0000000119573309Key Laboratory of Engineering Biology for Low-carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China ,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308 China
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7
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Hu D, Zhang Y, Liu D, Wang D, Tian C. PFK2/FBPase-2 is a potential target for metabolic engineering in the filamentous fungus Myceliophthora thermophila. Front Microbiol 2022; 13:1056694. [PMID: 36478865 PMCID: PMC9721465 DOI: 10.3389/fmicb.2022.1056694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/07/2022] [Indexed: 09/05/2023] Open
Abstract
The key enzyme 6-phosphofructo-2-kinase (PFK2)/fructose-2,6-bisphosphatase (FBPase-2) is responsible for regulating the rates of glycolysis and gluconeogenesis in eukaryotes. However, its functions and mechanisms in filamentous fungi remain largely enigmatic. In this study, we systematically investigated the function of this enzyme in Myceliophthora thermophila, a thermophilic filamentous fungus with great capacity to produce industrial enzymes and organic acids. Our results showed that the M. thermophila genome encodes three isomers, all with the PFK2/FBPase-2 structure: pfk2-a, pfk2-b, and pfk2-c. Overexpression of each gene revealed that endogenous expression of pfk2-c (PFK2 activity) promoted glucose metabolism, while overexpression of pfk2-a (FBPase-2 activity) inhibited strain growth. Using knockouts, we found that each gene was individually non-essential, but the triple knockout led to significantly slower growth compared with the wild-type strain. Only the pfk2-a single knockout exhibited 22.15% faster sugar metabolism, exerted through activation of 6-phosphofructo-1-kinase (PFK1), thereby significantly promoting glycolysis and the tricarboxylic acid cycle. The FBPase-2 deletion mutant strain also exhibited overflow metabolism, and knocking out pfk2-a was proved to be able to improve the production and synthesis rate of various metabolites, such as glycerol and malate. This is the first study to systematically investigate the function of PFK2/FBPase-2 in a thermophilic fungus, providing an effective target for metabolic engineering in filamentous fungi.
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Affiliation(s)
- Die Hu
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Yongli Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Defei Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Depei Wang
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
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8
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Guo W, Liu D, Li J, Sun W, Sun T, Wang X, Wang K, Liu Q, Tian C. Manipulation of an α-glucosidase in the industrial glucoamylase-producing Aspergillus niger strain O1 to decrease non-fermentable sugars production and increase glucoamylase activity. Front Microbiol 2022; 13:1029361. [PMID: 36338048 PMCID: PMC9633098 DOI: 10.3389/fmicb.2022.1029361] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 09/27/2022] [Indexed: 09/25/2023] Open
Abstract
Dextrose equivalent of glucose from starch hydrolysis is a critical index for starch-hydrolysis industry. Improving glucose yield and decreasing the non]-fermentable sugars which caused by transglycosylation activity of the enzymes during the starch saccharification is an important direction. In this study, we identified two key α-glucosidases responsible for producing non-fermentable sugars in an industrial glucoamylase-producing strain Aspergillus niger O1. The results showed the transglycosylation product panose was decreased by more than 88.0% in agdA /agdB double knock-out strains than strain O1. Additionally, the B-P1 domain of agdB was found accountable as starch hydrolysis activity only, and B-P1 overexpression in ΔA ΔB -21 significantly increased glucoamylase activity whereas keeping the glucoamylase cocktail low transglycosylation activity. The total amounts of the transglycosylation products isomaltose and panose were significantly decreased in final strain B-P1-3 by 40.7% and 44.5%, respectively. The application of engineered strains will decrease the cost and add the value of product for starch biorefinery.
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Affiliation(s)
- Wenzhu Guo
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Dandan Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Wenliang Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Tao Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | | | - Kefen Wang
- Longda Biotechnology Inc., Shandong, China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, China
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9
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Hao Y, Pan X, Xing R, You J, Hu M, Liu Z, Li X, Xu M, Rao Z. High-level production of L-valine in Escherichia coli using multi-modular engineering. BIORESOURCE TECHNOLOGY 2022; 359:127461. [PMID: 35700900 DOI: 10.1016/j.biortech.2022.127461] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/08/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
L-valine is a valuable amino acid in mammals that is used as the main component of feed additives. The low efficiency of the fermentation titer limits the industrial application of L-valine. Here, an L-valine-producing strain of Escherichia coli was obtained using a multi-modular strategy. Initially, a chassis strain was generated by mutagenesis and high-throughput screening. The L-valine biosynthetic pathway and transport module were modified to improve the L-valine titer. Subsequently, the transcription factors associated with L-valine biosynthesis were investigated. Overexpression of PdhR and inhibition of the expression of RpoS promoted L-valine synthesis. Finally, the NADPH supply was enhanced after the introduction of the heterologous Entner-Doudoroff (ED) pathway from Zymomonas mobilis. The strain VAL38 produced 92 g/L L-valine in a 5-L bioreactor with a yield of 0.34 g/g glucose. This strategy is provided as a reference for improving the production performance of cell factories for L-valine and its derivatives.
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Affiliation(s)
- Yanan Hao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Rufan Xing
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Mengkai Hu
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhifei Liu
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xiangfei Li
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Meijuan Xu
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
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10
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Liu D, Xu Z, Li J, Liu Q, Yuan Q, Guo Y, Ma H, Tian C. Reconstruction and analysis of genome-scale metabolic model for thermophilic fungus Myceliophthora thermophila. Biotechnol Bioeng 2022; 119:1926-1937. [PMID: 35257374 DOI: 10.1002/bit.28080] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/24/2022] [Accepted: 03/03/2022] [Indexed: 11/11/2022]
Abstract
Myceliophthora thermophila, a thermophilic fungus that can degrade and utilize all major polysaccharides in plant biomass, has great potential in biotechnological industries. Here, the first manually curated genome-scale metabolic model iDL1450 for M. thermophila was reconstructed using an auto-generating pipeline with thorough manual curation. The model contains 1450 genes, 2592 reactions and 1784 unique metabolites. High accuracy was shown in predictions related to carbon and nitrogen source utilization based on data obtained from Biolog experiments. Besides, metabolism profiles were analyzed using iDL1450 integrated with transcriptomics data of M. thermophila at various growth temperatures. The refined model provides new insights into thermophilic fungi metabolism and sheds light on model-driven strain design to improve biotechnological applications of this thermophilic lignocellulosic fungus. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Defei Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Zixiang Xu
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.,National Engineering Laboratory for Industrial Enzymes and Tianjin Engineering Research Center of Biocatalytic Technology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Qianqian Yuan
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.,Biodesign Center, Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Yanmei Guo
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Hongwu Ma
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.,Biodesign Center, Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.,National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
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11
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Yang YJ, Liu Y, Liu DD, Guo WZ, Wang LX, Wang XJ, Lv HX, Yang Y, Liu Q, Tian CG. Development of a flow cytometry-based plating-free system for strain engineering in industrial fungi. Appl Microbiol Biotechnol 2021; 106:713-727. [PMID: 34921331 DOI: 10.1007/s00253-021-11733-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/29/2021] [Accepted: 12/03/2021] [Indexed: 01/02/2023]
Abstract
Recent technical advances regarding filamentous fungi have accelerated the engineering of fungal-based production and benefited basic science. However, challenges still remain and limit the speed of fungal applications. For example, high-throughput technologies tailored to filamentous fungi are not yet commonly available for genetic modification. The currently used fungal genetic manipulations are time-consuming and laborious. Here, we developed a flow cytometry-based plating-free system to directly screen and isolate the transformed protoplasts in industrial fungi Myceliophthora thermophila and Aspergillus niger. This system combines genetic engineering via the 2A peptide and the CRISPR-Cas9 system, strain screening by flow cytometry, and direct sorting of colonies for deep-well-plate incubation and phenotypic analysis while avoiding culturing transformed protoplasts in plates, colony picking, conidiation, and cultivation. As a proof of concept, we successfully applied this system to generate the glucoamylase-hyperproducing strains MtYM6 and AnLM3 in M. thermophila and A. niger, respectively. Notably, the protein secretion level and enzyme activities in MtYM6 were 17.3- and 25.1-fold higher than in the host strain. Overall, these findings suggest that the flow cytometry-based plating-free system can be a convenient and efficient tool for strain engineering in fungal biotechnology. We expect this system to facilitate improvements of filamentous fungal strains for industrial applications. KEY POINTS: • Development of a flow cytometry-based plating-free (FCPF) system is presented. • Application of FCPF system in M. thermophila and A. niger for glucoamylase platform. • Hyper-produced strains MtYM6 and AnLM3 for glucoamylase production are generated.
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Affiliation(s)
- Yu-Jing Yang
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Yin Liu
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Dan-Dan Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Wen-Zhu Guo
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Li-Xian Wang
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China
| | - Xing-Ji Wang
- Longda Biotechnology Inc, 276400, Linyi, Shandong, China
| | - He-Xin Lv
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Yang Yang
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.
| | - Chao-Guang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308, China.
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12
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Li X, Bao T, Osire T, Qiao Z, Liu J, Zhang X, Xu M, Yang T, Rao Z. MarR-type transcription factor RosR regulates glutamate metabolism network and promotes accumulation of L-glutamate in Corynebacterium glutamicum G01. BIORESOURCE TECHNOLOGY 2021; 342:125945. [PMID: 34560435 DOI: 10.1016/j.biortech.2021.125945] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
Transcription factors (TFs) perform a crucial function in the regulation of amino acids biosynthesis. Here, TFs involved in L-glutamate biosynthesis in Corynebacterium glutamicum were investigated. Compared to transcriptomic results of C. glutamicum 13032, 7 TFs regulated to glutamate biosynthesis were indentifed in G01 and E01. Among them, RosR was demonstrated to regulate L-glutamate metabolic network by binding to the promoters of glnA, pqo, ilvB, ilvN, ilvC, ldhA, odhA, dstr1, fas, argJ, ak and pta. Overexpression of RosR in G01 resulted in significantly decreased by-products yield and improved L-glutamate titer (130.6 g/L) and yield (0.541 g/g from glucose) in fed-batch fermentation. This study demonstrated the L-glutamate production improved by the expression of TFs in C. glutamicum, which provided a good reference for the transcriptional regulation engineering of strains for amino acid biosynthesis and suggested further metabolic engineering of C. glutamicum for L-glutamate production.
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Affiliation(s)
- Xiangfei Li
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Teng Bao
- Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - Tolbert Osire
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhina Qiao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jiafeng Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xian Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Meijuan Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Taowei Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhiming Rao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
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13
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Zhang G, Chen Y, Li Q, Zhou J, Li J, Du G. Growth-coupled evolution and high-throughput screening assisted rapid enhancement for amylase-producing Bacillus licheniformis. BIORESOURCE TECHNOLOGY 2021; 337:125467. [PMID: 34320747 DOI: 10.1016/j.biortech.2021.125467] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
Bacillus licheniformis α-amylase is a thermostable enzyme used in industrial starch hydrolysis. However, difficulties in the genetic manipulation of B. licheniformis hamper further enhancement of α-amylase production. In this regard, adaptive evolution is a useful strategy for promoting the productivity of microbial hosts, although the success of this approach requires the application of suitable evolutionary stress. In this study, we designed a growth-coupled adaptive evolution model to enrich B. licheniformis strains with enhanced amylase productivity and utilization capacity of starch substrates. Single cells of high α-amylase-producing B. licheniformis were isolated using a droplet-based microfluidic platform. Clones with 67% higher α-amylase yield were obtained and analyzed by genome resequencing. Our findings confirmed that growth-coupled evolution combined with high-throughput screening is an efficient strategy for enhanced α-amylase production. In addition, we identified several potential target genes to guide further modification of the B. licheniformis host for efficient protein expression.
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Affiliation(s)
- Guoqiang Zhang
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
| | - Yukun Chen
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Qinghua Li
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jingwen Zhou
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jianghua Li
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Guocheng Du
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
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14
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The F-box protein gene exo- 1 is a target for reverse engineering enzyme hypersecretion in filamentous fungi. Proc Natl Acad Sci U S A 2021; 118:2025689118. [PMID: 34168079 DOI: 10.1073/pnas.2025689118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Carbohydrate active enzymes (CAZymes) are vital for the lignocellulose-based biorefinery. The development of hypersecreting fungal protein production hosts is therefore a major aim for both academia and industry. However, despite advances in our understanding of their regulation, the number of promising candidate genes for targeted strain engineering remains limited. Here, we resequenced the genome of the classical hypersecreting Neurospora crassa mutant exo-1 and identified the causative point of mutation to reside in the F-box protein-encoding gene, NCU09899. The corresponding deletion strain displayed amylase and invertase activities exceeding those of the carbon catabolite derepressed strain Δcre-1, while glucose repression was still mostly functional in Δexo-1 Surprisingly, RNA sequencing revealed that while plant cell wall degradation genes are broadly misexpressed in Δexo-1, only a small fraction of CAZyme genes and sugar transporters are up-regulated, indicating that EXO-1 affects specific regulatory factors. Aiming to elucidate the underlying mechanism of enzyme hypersecretion, we found the high secretion of amylases and invertase in Δexo-1 to be completely dependent on the transcriptional regulator COL-26. Furthermore, misregulation of COL-26, CRE-1, and cellular carbon and nitrogen metabolism was confirmed by proteomics. Finally, we successfully transferred the hypersecretion trait of the exo-1 disruption by reverse engineering into the industrially deployed fungus Myceliophthora thermophila using CRISPR-Cas9. Our identification of an important F-box protein demonstrates the strength of classical mutants combined with next-generation sequencing to uncover unanticipated candidates for engineering. These data contribute to a more complete understanding of CAZyme regulation and will facilitate targeted engineering of hypersecretion in further organisms of interest.
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15
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Jiang C, Lv G, Tu Y, Cheng X, Duan Y, Zeng B, He B. Applications of CRISPR/Cas9 in the Synthesis of Secondary Metabolites in Filamentous Fungi. Front Microbiol 2021; 12:638096. [PMID: 33643273 PMCID: PMC7905030 DOI: 10.3389/fmicb.2021.638096] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 01/18/2021] [Indexed: 12/19/2022] Open
Abstract
Filamentous fungi possess the capacity to produce a wide array of secondary metabolites with diverse biological activities and structures, such as lovastatin and swainsonine. With the advent of the post-genomic era, increasing amounts of cryptic or uncharacterized secondary metabolite biosynthetic gene clusters are continually being discovered. However, owing to the longstanding lack of versatile, comparatively simple, and highly efficient genetic manipulation techniques, the broader exploration of industrially important secondary metabolites has been hampered thus far. With the emergence of CRISPR/Cas9-based genome editing technology, this dilemma may be alleviated, as this advanced technique has revolutionized genetic research and enabled the exploitation and discovery of new bioactive compounds from filamentous fungi. In this review, we introduce the CRISPR/Cas9 system in detail and summarize the latest applications of CRISPR/Cas9-mediated genome editing in filamentous fungi. We also briefly introduce the specific applications of the CRISPR/Cas9 system and CRISPRa in the improvement of secondary metabolite contents and discovery of novel biologically active compounds in filamentous fungi, with specific examples noted. Additionally, we highlight and discuss some of the challenges and deficiencies of using the CRISPR/Cas9-based genome editing technology in research on the biosynthesis of secondary metabolites as well as future application of CRISPR/Cas9 strategy in filamentous fungi are highlighted and discussed.
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Affiliation(s)
- Chunmiao Jiang
- Jiangxi Key Laboratory of Bioprocess Engineering and Co-Innovation Center for In-Vitro Diagnostic Reagents and Devices of Jiangxi Province, College of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, China
| | - Gongbo Lv
- Jiangxi Key Laboratory of Bioprocess Engineering and Co-Innovation Center for In-Vitro Diagnostic Reagents and Devices of Jiangxi Province, College of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, China
| | - Yayi Tu
- Jiangxi Key Laboratory of Bioprocess Engineering and Co-Innovation Center for In-Vitro Diagnostic Reagents and Devices of Jiangxi Province, College of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, China
| | - Xiaojie Cheng
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Yitian Duan
- School of Information, Renmin University of China, Beijing, China
| | - Bin Zeng
- Jiangxi Key Laboratory of Bioprocess Engineering and Co-Innovation Center for In-Vitro Diagnostic Reagents and Devices of Jiangxi Province, College of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, China.,College of Pharmacy, Shenzhen Technology University, Shenzhen, China
| | - Bin He
- Jiangxi Key Laboratory of Bioprocess Engineering and Co-Innovation Center for In-Vitro Diagnostic Reagents and Devices of Jiangxi Province, College of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, China
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16
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Li J, Liu Q, Li J, Lin L, Li X, Zhang Y, Tian C. RCO-3 and COL-26 form an external-to-internal module that regulates the dual-affinity glucose transport system in Neurospora crassa. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:33. [PMID: 33509260 PMCID: PMC7841889 DOI: 10.1186/s13068-021-01877-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 01/07/2021] [Indexed: 05/13/2023]
Abstract
BACKGROUND Low- and high-affinity glucose transport system is a conserved strategy of microorganism to cope with environmental glucose fluctuation for their growth and competitiveness. In Neurospora crassa, the dual-affinity glucose transport system consists of a low-affinity glucose transporter GLT-1 and two high-affinity glucose transporters HGT-1/HGT-2, which play diverse roles in glucose transport, carbon metabolism, and cellulase expression regulation. However, the regulation of this dual-transporter system in response to environmental glucose fluctuation is not yet clear. RESULTS In this study, we report that a regulation module consisting of a downstream transcription factor COL-26 and an upstream non-transporting glucose sensor RCO-3 regulates the dual-affinity glucose transport system in N. crassa. COL-26 directly binds to the promoter regions of glt-1, hgt-1, and hgt-2, whereas RCO-3 is an upstream factor of the module whose deletion mutant resembles the Δcol-26 mutant phenotypically. Transcriptional profiling analysis revealed that Δcol-26 and Δrco-3 mutants had similar transcriptional profiles, and both mutants had impaired response to a glucose gradient. We also showed that the AMP-activated protein kinase (AMPK) complex is involved in regulation of the glucose transporters. AMPK is required for repression of glt-1 expression in starvation conditions by inhibiting the activity of RCO-3. CONCLUSIONS RCO-3 and COL-26 form an external-to-internal module that regulates the glucose dual-affinity transport system. Transcription factor COL-26 was identified as the key regulator. AMPK was also involved in the regulation of the dual-transporter system. Our findings provide novel insight into the molecular basis of glucose uptake and signaling in filamentous fungi, which may aid in the rational design of fungal strains for industrial purposes.
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Affiliation(s)
- Jinyang Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Liangcai Lin
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Xiaolin Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Yongli Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
- National Technology Innovation Center of Synthetic Biology, Tianjin, 300308 China
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17
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Zhang T, Liu H, Lv B, Li C. Regulating Strategies for Producing Carbohydrate Active Enzymes by Filamentous Fungal Cell Factories. Front Bioeng Biotechnol 2020; 8:691. [PMID: 32733865 PMCID: PMC7360787 DOI: 10.3389/fbioe.2020.00691] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 06/03/2020] [Indexed: 12/17/2022] Open
Abstract
Filamentous fungi are important eukaryotic organisms crucial in substrate degradation and carbon cycle on the earth and have been harnessed as cell factories for the production of proteins and other high value-added products in recent decades. As cell factories, filamentous fungi play a crucial role in industrial protein production as both native hosts and heterologous hosts. In this review, the regulation strategies of carbohydrate active enzyme expression at both transcription level and protein level are introduced, and the transcription regulations are highlighted with induction mechanism, signaling pathway, and promoter and transcription factor regulation. Afterward, the regulation strategies in protein level including suitable posttranslational modification, protein secretion enhancement, and protease reduction are also presented. Finally, the challenges and perspectives in this field are discussed. In this way, a comprehensive knowledge regarding carbohydrate active enzyme production regulation at both transcriptional and protein levels is provided with the particular goal of aiding in the practical application of filamentous fungi for industrial protein production.
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Affiliation(s)
- Teng Zhang
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Hu Liu
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Bo Lv
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Chun Li
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
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18
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Li F, Liu Q, Li X, Zhang C, Li J, Sun W, Liu D, Xiao D, Tian C. Construction of a new thermophilic fungus Myceliophthora thermophila platform for enzyme production using a versatile 2A peptide strategy combined with efficient CRISPR-Cas9 system. Biotechnol Lett 2020; 42:1181-1191. [PMID: 32253539 DOI: 10.1007/s10529-020-02882-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 03/31/2020] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To construct a new thermophilic platform for glucoamylase production through 2A peptide strategy combined with CRISPR-Cas9 system using Myceliophthora thermophila as host, thermophilic filamentous fungus with industrial attractiveness to produce enzymes and chemicals from biomass. RESULTS We adapted the viral 2A peptide approach for M. thermophila and constructed a bicistronic vector for co-expressing two heterologous genes MhglaA and egfp. We obtained positive transformants OE-MhglaA-gfp overexpressing MhGlaA-9 ×His-2A-eGFP through convenient fluorescence screening, western blotting and RT-qPCR. We purified and characterized the recombinant MhGlaA, which exhibited stability in a broader pH range of 3.0-9.0 and thermostable stability at 65 °C, suggesting its potential industrial application. Furthermore, to improve glucoamylase secretion, we genetically engineered the obtained strain OE-MhglaA-gfp through our efficient CRISPR/Cas9 system and generated the quintuple mutant OE-MhglaA-gfpOE-amyRΔalp-1Δres-1Δcre-1, in which protein productivity and amylase activity were increased by approximately 12.0- and 8.2-fold compared with WT. CONCLUSIONS The 2A peptide approach worked well in M. thermophila and can be used to heterologously co-express two different proteins, and thus in combination with efficient CRISPR-Cas system will accelerate establishing hyper-secretion platforms for biotechnological applications.
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Affiliation(s)
- Fangya Li
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, China.,Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Xiaolin Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Chenyang Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Wenliang Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Dandan Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Dongguang Xiao
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
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Li J, Zhang Y, Li J, Sun T, Tian C. Metabolic engineering of the cellulolytic thermophilic fungus Myceliophthora thermophila to produce ethanol from cellobiose. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:23. [PMID: 32021654 PMCID: PMC6995234 DOI: 10.1186/s13068-020-1661-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/21/2020] [Indexed: 05/28/2023]
Abstract
BACKGROUND Cellulosic biomass is a promising resource for bioethanol production. However, various sugars in plant biomass hydrolysates including cellodextrins, cellobiose, glucose, xylose, and arabinose, are poorly fermented by microbes. The commonly used ethanol-producing microbe Saccharomyces cerevisiae can usually only utilize glucose, although metabolically engineered strains that utilize xylose have been developed. Direct fermentation of cellobiose could avoid glucose repression during biomass fermentation, but applications of an engineered cellobiose-utilizing S. cerevisiae are still limited because of its long lag phase. Bioethanol production from biomass-derived sugars by a cellulolytic filamentous fungus would have many advantages for the biorefinery industry. RESULTS We selected Myceliophthora thermophila, a cellulolytic thermophilic filamentous fungus for metabolic engineering to produce ethanol from glucose and cellobiose. Ethanol production was increased by 57% from glucose but not cellobiose after introduction of ScADH1 into the wild-type (WT) strain. Further overexpression of a glucose transporter GLT-1 or the cellodextrin transport system (CDT-1/CDT-2) from N. crassa increased ethanol production by 131% from glucose or by 200% from cellobiose, respectively. Transcriptomic analysis of the engineered cellobiose-utilizing strain and WT when grown on cellobiose showed that genes involved in oxidation-reduction reactions and the stress response were downregulated, whereas those involved in protein biosynthesis were upregulated in this effective ethanol production strain. Turning down the expression of pyc gene results the final engineered strain with the ethanol production was further increased by 23%, reaching up to 11.3 g/L on cellobiose. CONCLUSIONS This is the first attempt to engineer the cellulolytic fungus M. thermophila to produce bioethanol from biomass-derived sugars such as glucose and cellobiose. The ethanol production can be improved about 4 times up to 11 grams per liter on cellobiose after a couple of genetic engineering. These results show that M. thermophila is a promising platform for bioethanol production from cellulosic materials in the future.
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Affiliation(s)
- Jinyang Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Yongli Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Tao Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
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Li J, Gu S, Zhao Z, Chen B, Liu Q, Sun T, Sun W, Tian C. Dissecting cellobiose metabolic pathway and its application in biorefinery through consolidated bioprocessing in Myceliophthora thermophila. Fungal Biol Biotechnol 2019; 6:21. [PMID: 31754437 PMCID: PMC6852783 DOI: 10.1186/s40694-019-0083-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/04/2019] [Indexed: 02/08/2023] Open
Abstract
Background Lignocellulosic biomass has long been recognized as a potential sustainable source for industrial applications. The costs associated with conversion of plant biomass to fermentable sugar represent a significant barrier to the production of cost-competitive biochemicals. Consolidated bioprocessing (CBP) is considered a potential breakthrough for achieving cost-efficient production of biomass-based fuels and commodity chemicals. During the degradation of cellulose, cellobiose (major end-product of cellulase activity) is catabolized by hydrolytic and phosphorolytic pathways in cellulolytic organisms. However, the details of the two intracellular cellobiose metabolism pathways in cellulolytic fungi remain to be uncovered. Results Using the engineered malic acid production fungal strain JG207, we demonstrated that the hydrolytic pathway by β-glucosidase and the phosphorolytic pathway by phosphorylase are both used for intracellular cellobiose metabolism in Myceliophthora thermophila, and the yield of malic acid can benefit from the energy advantages of phosphorolytic cleavage. There were obvious differences in regulation of the two cellobiose catabolic pathways depending on whether M. thermophila JG207 was grown on cellobiose or Avicel. Disruption of Mtcpp in strain JG207 led to decreased production of malic acid under cellobiose conditions, while expression levels of all three intracellular β-glucosidase genes were significantly up-regulated to rescue the impairment of the phosphorolytic pathway under Avicel conditions. When the flux of the hydrolytic pathway was reduced, we found that β-glucosidase encoded by bgl1 was the dominant enzyme in the hydrolytic pathway and deletion of bgl1 resulted in significant enhancement of protein secretion but reduction of malate production. Combining comprehensive manipulation of both cellobiose utilization pathways and enhancement of cellobiose uptake by overexpression of a cellobiose transporter, the final strain JG412Δbgl2Δbgl3 produced up to 101.2 g/L and 77.4 g/L malic acid from cellobiose and Avicel, respectively, which corresponded to respective yields of 1.35 g/g and 1.03 g/g, representing significant improvement over the starting strain JG207. Conclusions This is the first report of detailed investigation of intracellular cellobiose catabolism in cellulolytic fungus M. thermophila. These results provide insights that can be applied to industrial fungi for production of biofuels and biochemicals from cellobiose and cellulose.
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Affiliation(s)
- Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Shuying Gu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Zhen Zhao
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Bingchen Chen
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Tao Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Wenliang Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
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Vu VV, Hangasky JA, Detomasi TC, Henry SJW, Ngo ST, Span EA, Marletta MA. Substrate selectivity in starch polysaccharide monooxygenases. J Biol Chem 2019; 294:12157-12166. [PMID: 31235519 DOI: 10.1074/jbc.ra119.009509] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/21/2019] [Indexed: 11/06/2022] Open
Abstract
Degradation of polysaccharides is central to numerous biological and industrial processes. Starch-active polysaccharide monooxygenases (AA13 PMOs) oxidatively degrade starch and can potentially be used with industrial amylases to convert starch into a fermentable carbohydrate. The oxidative activities of the starch-active PMOs from the fungi Neurospora crassa and Myceliophthora thermophila, NcAA13 and MtAA13, respectively, on three different starch substrates are reported here. Using high-performance anion-exchange chromatography coupled with pulsed amperometry detection, we observed that both enzymes have significantly higher oxidative activity on amylose than on amylopectin and cornstarch. Analysis of the product distribution revealed that NcAA13 and MtAA13 more frequently oxidize glycosidic linkages separated by multiples of a helical turn consisting of six glucose units on the same amylose helix. Docking studies identified important residues that are involved in amylose binding and suggest that the shallow groove that spans the active-site surface of AA13 PMOs favors the binding of helical amylose substrates over nonhelical substrates. Truncations of NcAA13 that removed its native carbohydrate-binding module resulted in diminished binding to amylose, but truncated NcAA13 still favored amylose oxidation over other starch substrates. These findings establish that AA13 PMOs preferentially bind and oxidize the helical starch substrate amylose. Moreover, the product distributions of these two enzymes suggest a unique interaction with starch substrates.
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Affiliation(s)
- Van V Vu
- Nguyen Tat Thanh Hi-Tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City 70000, Vietnam.
| | - John A Hangasky
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720
| | - Tyler C Detomasi
- Department of Chemistry, University of California, Berkeley, California 94720
| | - Skylar J W Henry
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
| | - Son Tung Ngo
- Laboratory of Theoretical and Computational Biophysics, Ton Duc Thang University, Ho Chi Minh City 758307, Vietnam; Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 758307, Vietnam
| | - Elise A Span
- Biophysics Graduate Group, University of California, Berkeley, California 94720
| | - Michael A Marletta
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720; Department of Chemistry, University of California, Berkeley, California 94720; Department of Molecular and Cell Biology, University of California, Berkeley, California 94720.
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Strategies for gene disruption and expression in filamentous fungi. Appl Microbiol Biotechnol 2019; 103:6041-6059. [DOI: 10.1007/s00253-019-09953-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 02/02/2023]
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Developments and opportunities in fungal strain engineering for the production of novel enzymes and enzyme cocktails for plant biomass degradation. Biotechnol Adv 2019; 37:107361. [PMID: 30825514 DOI: 10.1016/j.biotechadv.2019.02.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/11/2019] [Accepted: 02/23/2019] [Indexed: 12/26/2022]
Abstract
Fungal strain engineering is commonly used in many areas of biotechnology, including the production of plant biomass degrading enzymes. Its aim varies from the production of specific enzymes to overall increased enzyme production levels and modification of the composition of the enzyme set that is produced by the fungus. Strain engineering involves a diverse range of methodologies, including classical mutagenesis, genetic engineering and genome editing. In this review, the main approaches for strain engineering of filamentous fungi in the field of plant biomass degradation will be discussed, including recent and not yet implemented methods, such as CRISPR/Cas9 genome editing and adaptive evolution.
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Gu S, Li J, Chen B, Sun T, Liu Q, Xiao D, Tian C. Metabolic engineering of the thermophilic filamentous fungus Myceliophthora thermophila to produce fumaric acid. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:323. [PMID: 30534201 PMCID: PMC6278111 DOI: 10.1186/s13068-018-1319-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/22/2018] [Indexed: 05/16/2023]
Abstract
BACKGROUND Fumaric acid is widely used in food and pharmaceutical industries and is recognized as a versatile industrial chemical feedstock. Increasing concerns about energy and environmental problems have resulted in a focus on fumaric acid production by microbial fermentation via bioconversion of renewable feedstocks. Filamentous fungi are the predominant microorganisms used to produce organic acids, including fumaric acid, and most studies to date have focused on Rhizopus species. Thermophilic filamentous fungi have many advantages for the production of compounds by industrial fermentation. However, no previous studies have focused on fumaric acid production by thermophilic fungi. RESULTS We explored the feasibility of producing fumarate by metabolically engineering Myceliophthora thermophila using the CRISPR/Cas9 system. Screening of fumarases suggested that the fumarase from Candida krusei was the most suitable for efficient production of fumaric acid in M. thermophila. Introducing the C. krusei fumarase into M. thermophila increased the titer of fumaric acid by threefold. To further increase fumarate production, the intracellular fumarate digestion pathway was disrupted. After deletion of the two fumarate reductase and the mitochondrial fumarase genes of M. thermophila, the resulting strain exhibited a 2.33-fold increase in fumarate titer. Increasing the pool size of malate, the precursor of fumaric acid, significantly increased the final fumaric acid titer. Finally, disruption of the malate-aspartate shuttle increased the intracellular malate content by 2.16-fold and extracellular fumaric acid titer by 42%, compared with that of the parental strain. The strategic metabolic engineering of multiple genes resulted in a final strain that could produce up to 17 g/L fumaric acid from glucose in a fed-batch fermentation process. CONCLUSIONS This is the first metabolic engineering study on the production of fumaric acid by the thermophilic filamentous fungus M. thermophila. This cellulolytic fungal platform provides a promising method for the sustainable and efficient-cost production of fumaric acid from lignocellulose-derived carbon sources in the future.
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Affiliation(s)
- Shuying Gu
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457 China
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Jingen Li
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Bingchen Chen
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Tao Sun
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Qian Liu
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
| | - Dongguang Xiao
- College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457 China
| | - Chaoguang Tian
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308 China
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