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Saqib A, -ur-Rehman S, Ali H, Hassan N, Ali A, Rashid MH. Gama rays mediated improvement of catalytic efficiency and thermostability of glucoamylase by replacing active site leucine to isoleucene from super koji (Aspergillus oryzae). PLoS One 2025; 20:e0319261. [PMID: 40249742 PMCID: PMC12007714 DOI: 10.1371/journal.pone.0319261] [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: 11/24/2024] [Accepted: 01/30/2025] [Indexed: 04/20/2025] Open
Abstract
Glucoamylase is considered as an essential enzyme in food industry. However, lowere catalytic efficiency and weak thermostability confine its application in food industry. Therefore, the current study was aimed to improve catalytic efficiency and thermostability of glucoamylase by replacing active site leucine to isoleucene from Super Koji (Aspergillus oryzae) using gama rays mediated point mutation. High catalytic efficiency and thermostability of glucoamylase from mutant Aspergillus oryzae M-60(5) (screened from 51 mutants) was achieved due to a point mutation, i.e., Leu203 → lle in active site. The SDS-PAGE molecular mass of parent and mutant glucoamylase was 63.1 kDa, while mutant glucoamylase showed; productivity = 9.7 U ml‒1, kinetic constants kcat = 118 (1.62 fold), (kcat/Km) = 1899 (4.75 fold) and half-life at 55 °C for 45 min (1.92 fold). Thermodynamics parameters for starch hydrolysis of parent glucoamylase were; ΔH*= 47.755 kJ mol‒1 and ΔG*= 67.975 kJ mol‒1 while for mutant ΔH*= 44.263kJ mol‒1 and ΔG*= 66.514 kJ mol‒1. The ΔG* of irreversible thermostability for parent and mutant at 55 °C was 104.95 kJ mol‒1 and 101.52 kJ mol‒1respectively. The point mutation altered the conformation of the glucoamylase active site that contributed to improve the functional energy (ΔG*), resulted the stabilization of transition state which made it thermostable and highly efficient in starch hydrolysis.
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Affiliation(s)
- Anam Saqib
- National Institute for Biotechnology and Genetic Engineering (NIBGE)—College, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
- QuinTech Center for Applied Sciences (QCAS), Lahore, Pakistan
| | - Saif -ur-Rehman
- National Institute for Biotechnology and Genetic Engineering (NIBGE)—College, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Hazrat Ali
- National Institute for Biotechnology and Genetic Engineering (NIBGE)—College, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Noor Hassan
- National Institute for Biotechnology and Genetic Engineering (NIBGE)—College, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Asad Ali
- National Institute for Biotechnology and Genetic Engineering (NIBGE)—College, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Muhammad Hamid Rashid
- National Institute for Biotechnology and Genetic Engineering (NIBGE)—College, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
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2
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Wang X, Gao J, Wu J, Li X, Li J, Li H, Wang S. Poly-γ-glutamic production by solid-state fermentation of Bacillus natto in ammonia nitrogen movement and soil water retention processes. Enzyme Microb Technol 2024; 182:110543. [PMID: 39515150 DOI: 10.1016/j.enzmictec.2024.110543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2024] [Revised: 10/25/2024] [Accepted: 10/30/2024] [Indexed: 11/16/2024]
Abstract
A high polyglutamic acid (γ-PGA) producing strain of Bacillus natto UV-40-50 was screened by ultraviolet mutagenesis treatment and identified as still belonging to the Bacillus specie. The optimal fermentation medium composition for solid state fermentation (SSF) of B. natto strain UV-40-50 strain was determined by one-way analysis of variance, under which the yield of γ-PGA was 55.19 g/kg, and the presence and molecular weight of γ-PGA in the γ-PGA-purified samples were determined by a series of characterizations. The purification ability of the unseparated solid fermentation product (SFP) on ammonia nitrogen and nitrite in the water column, as well as its effect on soil water retention, germination rate and seedling length of lettuce and cabbage were further investigated. The results showed that the addition of 1 g/m3 SFP could effectively remove more than 60 % of ammonia nitrogen and more than 40 % of nitrite in the water body; the addition of 0.01 % SFP could increase the water retention capacity of cabbage soil by 2.13 times, and increase the water retention capacity of lettuce soil by 12 %; at the same time, the SFP could also significantly increase the germination rate and seedling length of both cabbage and lettuce.
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Affiliation(s)
- Xin Wang
- School of Marine Science and Biological Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Jie Gao
- School of Biology and Brewing Engineering, Taishan University, 271021, China
| | - Jiahui Wu
- School of Marine Science and Biological Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Xuan Li
- School of Marine Science and Biological Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Junxun Li
- Shandong Taishan Shengliyuan Group Co., Ltd, Tianan 271000, China.
| | - Haihong Li
- Shandong Taishan Shengliyuan Group Co., Ltd, Tianan 271000, China
| | - Songlin Wang
- School of Marine Science and Biological Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China.
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3
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Yao H, Liu S, Liu T, Ren D, Zhou Z, Yang Q, Mao J. Microbial-derived salt-tolerant proteases and their applications in high-salt traditional soybean fermented foods: a review. BIORESOUR BIOPROCESS 2023; 10:82. [PMID: 38647906 PMCID: PMC10992980 DOI: 10.1186/s40643-023-00704-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 10/31/2023] [Indexed: 04/25/2024] Open
Abstract
Different microorganisms can produce different proteases, which can adapt to different industrial requirements such as pH, temperature, and pressure. Salt-tolerant proteases (STPs) from microorganisms exhibit higher salt tolerance, wider adaptability, and more efficient catalytic ability under extreme conditions compared to conventional proteases. These unique enzymes hold great promise for applications in various industries including food, medicine, environmental protection, agriculture, detergents, dyes, and others. Scientific studies on microbial-derived STPs have been widely reported, but there has been little systematic review of microbial-derived STPs and their application in high-salt conventional soybean fermentable foods. This review presents the STP-producing microbial species and their selection methods, and summarizes and analyzes the salt tolerance mechanisms of the microorganisms. It also outlines various techniques for the isolation and purification of STPs from microorganisms and discusses the salt tolerance mechanisms of STPs. Furthermore, this review demonstrates the contribution of modern biotechnology in the screening of novel microbial-derived STPs and their improvement in salt tolerance. It highlights the potential applications and commercial value of salt-tolerant microorganisms and STPs in high-salt traditional soy fermented foods. The review ends with concluding remarks on the challenges and future directions for microbial-derived STPs. This review provides valuable insights into the separation, purification, performance enhancement, and application of microbial-derived STPs in traditional fermented foods.
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Affiliation(s)
- Hongli Yao
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Department of Biology and Food Engineering, Bozhou University, Bozhou, 236800, Anhui, China
| | - Shuangping Liu
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, 511458, Guangdong, China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Jiangnan University (Shaoxing) Industrial Technology Research Institute, Shaoxing, 31200, Zhejiang, China
- National Engineering Research Center of Huangjiu, Zhejiang Guyuelongshan Shaoxing Wine CO., LTD, Shaoxing, 646000, Zhejiang, China
| | - Tiantian Liu
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Jiangnan University (Shaoxing) Industrial Technology Research Institute, Shaoxing, 31200, Zhejiang, China
- National Engineering Research Center of Huangjiu, Zhejiang Guyuelongshan Shaoxing Wine CO., LTD, Shaoxing, 646000, Zhejiang, China
| | - Dongliang Ren
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Zhilei Zhou
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, 511458, Guangdong, China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Jiangnan University (Shaoxing) Industrial Technology Research Institute, Shaoxing, 31200, Zhejiang, China
- National Engineering Research Center of Huangjiu, Zhejiang Guyuelongshan Shaoxing Wine CO., LTD, Shaoxing, 646000, Zhejiang, China
| | - Qilin Yang
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China
| | - Jian Mao
- National Engineering Research Center of Cereal Fermentation and Food Biomanufacturing, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
- Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, 511458, Guangdong, China.
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, Jiangsu, China.
- Jiangnan University (Shaoxing) Industrial Technology Research Institute, Shaoxing, 31200, Zhejiang, China.
- National Engineering Research Center of Huangjiu, Zhejiang Guyuelongshan Shaoxing Wine CO., LTD, Shaoxing, 646000, Zhejiang, China.
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Gao X, Zhao X, Hu F, Fu J, Zhang Z, Liu Z, Wang B, He R, Ma H, Ho CT. The latest advances on soy sauce research in the past decade: Emphasis on the advances in China. Food Res Int 2023; 173:113407. [PMID: 37803742 DOI: 10.1016/j.foodres.2023.113407] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/24/2023] [Accepted: 08/26/2023] [Indexed: 10/08/2023]
Abstract
As an indispensable soybean-fermented condiment, soy sauce is extensively utilized in catering, daily cooking and food industry in East Asia and Southeast Asia and is becoming popular in the whole world. In the past decade, researchers began to pay great importance to the scientific research of soy sauce, which remarkably promoted the advances on fermentation strains, quality, safety, function and other aspects of soy sauce. Of them, the screening and reconstruction of Aspergillus oryzae with high-yield of salt and acid-tolerant proteases, mechanism of soy sauce flavor formation, improvement of soy sauce quality through the combination of novel physical processing technique and microbial/enzyme, separation and identification of soy sauce functional components are attracting more attention of researchers, and related achievements have been reported continually. Meanwhile, we pointed out the drawbacks of the above research and the future research directions based on published literature and our knowledge. We believe that this review can provide an insightful reference for international related researchers to understand the advances on soy sauce research.
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Affiliation(s)
- Xianli Gao
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Xue Zhao
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Feng Hu
- Guangdong Meiweixian Flavoring Foods Co., Ltd., 1 Chubang Road, Zhongshan 5284012, China.
| | - Jiangyan Fu
- Guangdong Meiweixian Flavoring Foods Co., Ltd., 1 Chubang Road, Zhongshan 5284012, China.
| | - Zhankai Zhang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Zhan Liu
- Guangdong Meiweixian Flavoring Foods Co., Ltd., 1 Chubang Road, Zhongshan 5284012, China.
| | - Bo Wang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Ronghai He
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Haile Ma
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
| | - Chi-Tang Ho
- Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA.
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5
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Li J, Liu B, Feng X, Zhang M, Ding T, Zhao Y, Wang C. Comparative proteome and volatile metabolome analysis of Aspergillus oryzae 3.042 and Aspergillus sojae 3.495 during koji fermentation. Food Res Int 2023; 165:112527. [PMID: 36869527 DOI: 10.1016/j.foodres.2023.112527] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 01/09/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023]
Abstract
Aspergillus oryzae 3.042 and Aspergillus sojae 3.495 are crucial starters for fermented soybean foods since their abundant secreted enzymes. This study aimed to compare the differences in protein secretion between A. oryzae 3.042 and A. sojae 3.495 during the soy sauce koji fermentation and the effect on volatile metabolites to understand the fermentation characteristics of the strains better. Label-free proteomics detected 210 differentially expressed proteins (DEPs) enriched in amino acid metabolism and protein folding, sorting and degradation pathways. Subsequently, extracellular enzyme analysis showed that three peptidases, including peptide hydrolase, dipeptidyl aminopeptidase, and peptidase S41, were up-regulated in A. sojae 3.495. Seven carbohydrases, including α-galactosidase, endo-arabinase, β-glucosidase, α-galactosidase, α-glucuronidase, arabinan-endo 1,5-α-l-arabinase, and endo-1,4-β-xylanase were up-regulated in A. oryzae 3.042, contributing to the difference in enzyme activity. Significantly different extracellular enzymes influenced the content of volatile alcohols, aldehydes and esters such as (R, R)-2,3-butanediol, 1-hexanol, hexanal, decanal, ethyl l-lactate and methyl myristate in both strains, which affected the type of aroma of koji. Overall, this study revealed the differences in molecular mechanisms between A. oryzae 3.042 and A. sojae 3.495 under solid-state fermentation, providing a reference for targeted enhancement strains.
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Affiliation(s)
- Jingyao Li
- "State Key Laboratory of Food Nutrition and Safety", Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economy Technological Development Area, Tianjin 300457, People Republic of China
| | - Bin Liu
- College of Biological and Environmental Engineering, Binzhou University, 391 Huanghe 5th Road, 256603 Binzhou City, Shandong Province, China
| | - Xiaojuan Feng
- "State Key Laboratory of Food Nutrition and Safety", Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economy Technological Development Area, Tianjin 300457, People Republic of China
| | - Mengli Zhang
- "State Key Laboratory of Food Nutrition and Safety", Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economy Technological Development Area, Tianjin 300457, People Republic of China
| | - Tingting Ding
- "State Key Laboratory of Food Nutrition and Safety", Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economy Technological Development Area, Tianjin 300457, People Republic of China
| | - Yue Zhao
- "State Key Laboratory of Food Nutrition and Safety", Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economy Technological Development Area, Tianjin 300457, People Republic of China
| | - Chunling Wang
- "State Key Laboratory of Food Nutrition and Safety", Key Laboratory of Food Nutrition and Safety, Ministry of Education, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, No.29, 13th Avenue, Tianjin Economy Technological Development Area, Tianjin 300457, People Republic of China.
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6
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Zhang L, Kang L, Xu Y. Phenotypic, Genomic, and Transcriptomic Comparison of Industrial Aspergillus oryzae Used in Chinese and Japanese Soy Sauce: Analysis of Key Proteolytic Enzymes Produced by Koji Molds. Microbiol Spectr 2023; 11:e0083622. [PMID: 36744888 PMCID: PMC10100866 DOI: 10.1128/spectrum.00836-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 01/11/2023] [Indexed: 02/07/2023] Open
Abstract
Aspergillus oryzae, which generates numerous enzymes for the breakdown of raw materials, is an essential koji mold in soy sauce production. For better soy sauce productivity and flavor quality, China and Japan have developed their own industrial A. oryzae strains at distinct evolutionary branches for use in soy sauce production for decades. However, systematic comparison between the two national industrial strains has been poorly conducted, and thus we have not been able to generate adequate knowledge, especially regarding what are the key hydrolytic enzymes produced by A. oryzae during koji production. This study sequenced and assembled three high-quality genome sequences of industrial A. oryzae originating from China and Japan. Based on the genome sequences, a phylogenetic tree analysis was performed and revealed the evolutional distances between the two national industrial koji molds. Meanwhile, a comparative phenotypic analysis revealed that the two national industrial strains differed in growth and catalytic characteristics, particularly in proteolytic enzyme activities. To investigate the molecular mechanism underlying the phenotypic difference, we conducted systematic comparative genome and transcriptome investigations. We found minor differences in the quantity and diversity of proteolytic enzyme genes between Chinese and Japanese koji molds, while the protease secretion ratio and transcriptional level were dissimilar. We identified 58 potential important enzymes associated with high protein breakdown efficiency during industrial koji fermentation by combining comparative phenotypic and transcriptome data. More research is required to confirm the function of these putative key hydrolytic enzymes. IMPORTANCE Aspergillus oryzae is widely used as an industrial koji mold for soy sauce brewing due to its powerful raw material decomposition capability. Although various proteases in A. oryzae have been identified, it remains a challenge to find essential enzymes involved in soy sauce production. Generally, the industrial A. oryzae used in soy sauce brewing has excellent proteolytic activity. Based on this, we analyzed key proteolytic enzymes according to a comparison of the genome and transcriptome between three industrial strains. This study found little difference in gene numbers and mutations of proteolytic enzymes between three industrial A. oryzae strains. However, variations in protease secretion ratio and transcriptome were discovered between industrial strains. Based on that, we generated 58 candidate key proteolytic enzymes. This work comprehensively analyzed three industrial koji molds, revealing genome development under separate artificial domestication and helping in the study of key proteolytic enzymes during soy sauce production.
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Affiliation(s)
- Lijie Zhang
- Laboratory of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Le Kang
- Laboratory of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Yan Xu
- Laboratory of Brewing Microbiology and Applied Enzymology, Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
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7
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Lu F, Chao J, Zhao X, Betchem G, Ding Y, Yang X, Li Y, Ma H. Enhancing protease activity of Bacillus subtilis using UV-laser random mutagenesis and high-throughput screening. Process Biochem 2022. [DOI: 10.1016/j.procbio.2022.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Maeda T, Shibai A, Yokoi N, Tarusawa Y, Kawada M, Kotani H, Furusawa C. Mutational property of newly identified mutagen l-glutamic acid γ-hydrazide in Escherichia coli. Mutat Res 2021; 823:111759. [PMID: 34304126 DOI: 10.1016/j.mrfmmm.2021.111759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 06/07/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
We previously found that an l-glutamine analog l-glutamic acid γ-hydrazide has high mutagenic activity through the high-throughput laboratory evolution of Escherichia coli. In this study, mutagenicity and mutational property of l-glutamic acid γ-hydrazide were examined by the Ames test and mutation accumulation experiments using E. coli. The Ames test revealed that l-glutamic acid γ-hydrazide showed higher mutagenic activity without metabolic activation than known mutagens 2-aminoanthracene, and cobalt(II) acetate tetrahydrate. This result indicates that l-glutamic acid γ-hydrazide does not require metabolic activation for mutagenic activity in E. coli. Mutation accumulation experiments and whole-genome sequencing analysis revealed the number and spectrum of the accumulated mutations with or without l-glutamic acid γ-hydrazide. In the presence of l-glutamic acid γ-hydrazide, MDS42 strain accumulated 392.3 ± 116.2 point mutations during 30 passages corresponding to 777 generations, while MDS42 strain accumulated 1.5 ± 2.5 point mutations without l-glutamic acid γ-hydrazide during 50 passages corresponding to 1341 generations. The mutational spectrum of l-glutamic acid γ-hydrazide was G/C to A/T transition (82.2 ± 4.3 %) and A/T to G/C transition (17.4 ± 4.3 %). These results indicated that l-glutamic acid γ-hydrazide has a strong mutagenic activity.
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Affiliation(s)
- Tomoya Maeda
- RIKEN Center for Biosystems Dynamics Research, 6-2-3 Furuedai, Suita, Osaka, 565-0874, Japan.
| | - Atsushi Shibai
- RIKEN Center for Biosystems Dynamics Research, 6-2-3 Furuedai, Suita, Osaka, 565-0874, Japan
| | - Naomi Yokoi
- RIKEN Center for Biosystems Dynamics Research, 6-2-3 Furuedai, Suita, Osaka, 565-0874, Japan
| | - Yumeko Tarusawa
- RIKEN Center for Biosystems Dynamics Research, 6-2-3 Furuedai, Suita, Osaka, 565-0874, Japan
| | - Masako Kawada
- RIKEN Center for Biosystems Dynamics Research, 6-2-3 Furuedai, Suita, Osaka, 565-0874, Japan
| | - Hazuki Kotani
- RIKEN Center for Biosystems Dynamics Research, 6-2-3 Furuedai, Suita, Osaka, 565-0874, Japan
| | - Chikara Furusawa
- RIKEN Center for Biosystems Dynamics Research, 6-2-3 Furuedai, Suita, Osaka, 565-0874, Japan; Department of Physics, The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-0033, Japan; Universal Biology Institute, The University of Tokyo, 7-3-1 Hongo, Tokyo, 113-0033, Japan
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9
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Ji L, Wang J, Luo Q, Ding Q, Tang W, Chen X, Liu L. Enhancing L-malate production of Aspergillus oryzae by nitrogen regulation strategy. Appl Microbiol Biotechnol 2021; 105:3101-3113. [PMID: 33818672 DOI: 10.1007/s00253-021-11149-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/14/2021] [Accepted: 01/26/2021] [Indexed: 12/01/2022]
Abstract
Regulating morphology engineering and fermentation of Aspergillus oryzae makes it possible to increase the titer of L-malate. However, the existing L-malate-producing strain has limited L-malate production capacity and the fermentation process is insufficiently mature, which cannot meet the needs of industrial L-malate production. To further increase the L-malate production capacity of A. oryzae, we screened out a mutant strain (FMME-S-38) that produced 79.8 g/L L-malate in 250-mL shake flasks, using a newly developed screening system based on colony morphology on the plate. We further compared the extracellular nitrogen (N1) and intracellular nitrogen (N2) contents of the control and mutant strain (FMME-S-38) to determine the relationship between the curve of nitrogen content (N1 and N2) and the L-malate titer. This correlation was then used to optimize the conditions for developing a novel nitrogen supply strategy (initial tryptone concentration of 6.5 g/L and feeding with 3 g/L tryptone at 24 h). Fermentation in a 7.5-L fermentor under the optimized conditions further increased the titer and productivity of L-malate to 143.3 g/L and 1.19 g/L/h, respectively, corresponding to 164.9 g/L and 1.14 g/L/h in a 30-L fermentor. This nitrogen regulation-based strategy cannot only enhance industrial-scale L-malate production but also has generalizability and the potential to increase the production of similar metabolites.Key Points• Construction of a new screening system based on colony morphology on the plate.• A novel nitrogen regulation strategy used to regulate the production of L-malate.• A nitrogen supply strategy used to maximize the production of L-malate.
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Affiliation(s)
- Lihao Ji
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Ju Wang
- College of Food Engineering, Anhui Science and Technology University, Chuzhou, 233100, Anhui, China
| | - Qiuling Luo
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Qiang Ding
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Wenxiu Tang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China. .,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, 214122, China.
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