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Wang S, Xue Y, Zhang P, Yan Q, Li Y, Jiang Z. CRISPR/Cas9 System-Mediated Multi-copy Expression of an Alkaline Serine Protease in Aspergillus niger for the Production of XOD-Inhibitory Peptides. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:15194-15203. [PMID: 37807677 DOI: 10.1021/acs.jafc.3c04138] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
CRISPR/Cas9 system-mediated multi-copy expression of an alkaline serine protease (AoproS8) from Aspergillus oryzae was successfully built in Aspergillus niger. Furthermore, AoproS8 was continuously knocked in the glaA, amyA, and aamy gene loci in A. niger to construct multi-copy expression strains. The yield of the AoproS8 3.0 strain was 2.1 times higher than that of the AoproS8 1.0 strain. Then, a high protease activity of 11,023.2 U/mL with a protein concentration of 10.8 mg/mL was obtained through fed-batch fermentation in a 5 L fermenter. This is the first report on the high-level expression of alkaline serine proteases in A. niger. AoproS8 showed optimal activity at pH 9.0 and 40 °C. It was used for the production of xanthine oxidase (XOD)-inhibitory peptides from eight food processing protein by-products. Among them, the duck hemoglobin hydrolysates showed the highest XOD-inhibitory activity with an IC50 value of 2.39 mg/mL. Thus, our work provides a useful way for efficient expression of proteases in A. niger and high-value utilization of protein by-products.
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Affiliation(s)
- Shounan Wang
- Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Yibin Xue
- Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Peng Zhang
- College of Engineering, China Agricultural University, Beijing 100083, China
| | - Qiaojuan Yan
- College of Engineering, China Agricultural University, Beijing 100083, China
| | - Yanxiao Li
- College of Engineering, China Agricultural University, Beijing 100083, China
| | - Zhengqiang Jiang
- Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
- Food Laboratory of Zhongyuan, Luohe City 462000, Henan Province, China
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Zhu H, Li T, Li C, Liu Y, Miao Y, Liu D, Shen Q. Intracellular kynurenine promotes acetaldehyde accumulation, further inducing the apoptosis in soil beneficial fungi Trichoderma guizhouense NJAU4742 under acid stress. Environ Microbiol 2023; 25:331-351. [PMID: 36367399 DOI: 10.1111/1462-2920.16286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/10/2022] [Indexed: 11/13/2022]
Abstract
In this study, the growth of fungi Trichoderma guizhouense NJAU4742 was significantly inhibited under acid stress, and the genes related to acid stress were identified based on transcriptome analysis. Four genes including tna1, adh2/4, and bna3 were significantly up-regulated. Meanwhile, intracellular hydrogen ions accumulated under acid stress, and ATP synthesis was induced to transport hydrogen ions to maintain hydrogen ion balance. The enhancement of glycolysis pathway was also detected, and a large amount of pyruvic acid from glycolysis was accumulated due to the activity limitation of PDH enzymes. Finally, acetaldehyde accumulated, resulting in the induction of adh2/4. In order to cope with stress caused by acetaldehyde, cells enhanced the synthesis of NAD+ by increasing the expression of tna1 and bna3 genes. NAD+ effectively improved the antioxidant capacity of cells, but the NAD+ supplement pathway mediated by bna3 could also cause the accumulation of kynurenine (KYN), which was an inducer of apoptosis. In addition, KYN had a specific promoting effect on acetaldehyde synthesis by improving the expression of eno2 gene, which led to the extremely high intracellular acetaldehyde in the cell under acidic stress. Our findings provided a route to better understand the response of filamentous fungi under acid stress.
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Affiliation(s)
- Han Zhu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Jiangsu, People's Republic of China
- Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Tuo Li
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Jiangsu, People's Republic of China
- Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Chi Li
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Jiangsu, People's Republic of China
- Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Yang Liu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Jiangsu, People's Republic of China
- Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Youzhi Miao
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Jiangsu, People's Republic of China
- Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Dongyang Liu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Jiangsu, People's Republic of China
- Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Qirong Shen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Wastes, Educational Ministry Engineering Center of Resource-saving fertilizers, Jiangsu, People's Republic of China
- Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
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Sun X, Liang Y, Wang Y, Zhang H, Zhao T, Yao B, Luo H, Huang H, Su X. Simultaneous manipulation of multiple genes within a same regulatory stage for iterative evolution of Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:26. [PMID: 35248141 PMCID: PMC8898424 DOI: 10.1186/s13068-022-02122-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/19/2022] [Indexed: 11/12/2022]
Abstract
Background While there is growing interest in developing non-canonical filamentous fungi as hosts for producing secretory proteins, genetic engineering of filamentous fungi for improved expression often relies heavily on the understanding of regulatory mechanisms. Results In this study, using the cellulase-producing filamentous fungus Trichoderma reesei as a model system, we designed a semi-rational strategy by arbitrarily dividing the regulation of cellulase production into three main stages-transcription, secretion, and cell metabolism. Selected regulatory or functional genes that had been experimentally verified or predicted to enhance cellulase production were overexpressed using strong inducible or constitutive promoters, while those that would inhibit cellulase production were repressed via RNAi-mediated gene silencing. A T. reesei strain expressing the surface-displayed DsRed fluorescent protein was used as the recipient strain. After three consecutive rounds of engineering, the cellulase activity increased to up to 4.35-fold and the protein concentration increased to up to 2.97-fold in the genetically modified strain. Conclusions We demonstrated that, as a proof-of-concept, selected regulatory or functional genes within an arbitrarily defined stage could be pooled to stimulate secretory cellulase production, and moreover, this method could be iteratively used for further improvement. This method is semi-rational and can essentially be used in filamentous fungi with little regulatory information. Supplementary Information The online version contains supplementary material available at 10.1186/s13068-022-02122-0.
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Exploring the multi-level regulation of lignocellulases in the filamentous fungus Trichoderma guizhouense NJAU4742 from an omics perspective. Microb Cell Fact 2022; 21:144. [PMID: 35842666 PMCID: PMC9288086 DOI: 10.1186/s12934-022-01869-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 07/07/2022] [Indexed: 11/18/2022] Open
Abstract
Background Filamentous fungi are highly efficient at deconstructing plant biomass by secreting a variety of enzymes, but the complex enzymatic regulation underlying this process is not conserved and remains unclear. Results In this study, cellulases and xylanases could specifically respond to Avicel- and xylan-induction, respectively, in lignocellulose-degrading strain Trichoderma guizhouense NJAU4742, however, the differentially regulated cellulases and xylanases were both under the absolute control of the same TgXyr1-mediated pathway. Further analysis showed that Avicel could specifically induce cellulase expression, which supported the existence of an unknown specific regulator of cellulases in strain NJAU4742. The xylanase secretion is very complex, GH10 endoxylanases could only be induced by Avicel, while, other major xylanases were significantly induced by both Avicel and xylan. For GH10 xylanases, an unknown specific regulator was also deduced to exist. Meanwhile, the post-transcriptional inhibition was subsequently suggested to stop the Avicel-induced xylanases secretion, which explained the specifically high xylanase activities when induced by xylan in strain NJAU4742. Additionally, an economical strategy used by strain NJAU4742 was proposed to sense the environmental lignocellulose under the carbon starvation condition, that only slightly activating 4 lignocellulose-degrading genes before largely secreting all 33 TgXyr1-controlled lignocellulases if confirming the existence of lignocellulose components. Conclusions This study, aiming to explore the unknown mechanisms of plant biomass-degrading enzymes regulation through the combined omics analysis, will open directions for in-depth understanding the complex carbon utilization in filamentous fungi. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01869-3.
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