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Zhang Y, Cheng T, Zhao F, Yi Y, Li Q, Lu Z, Wu M, Wang T, Liu X. [Immobilizing engineered Escherichia coli cells into zeolitic imidazolate framework 8 for efficient biosynthesis of Ala-Gln]. Sheng Wu Gong Cheng Xue Bao 2023; 39:1131-1141. [PMID: 36994577 DOI: 10.13345/j.cjb.220848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
The α-amino acid ester acyltransferase (SAET) from Sphingobacterium siyangensis is one of the enzymes with the highest catalytic ability for the biosynthesis of l-alanyl-l-glutamine (Ala-Gln) with unprotected l-alanine methylester and l-glutamine. To improve the catalytic performance of SAET, a one-step method was used to rapidly prepare the immobilized cells (SAET@ZIF-8) in the aqueous system. The engineered Escherichia coli (E. coli) expressing SAET was encapsulated into the imidazole framework structure of metal organic zeolite (ZIF-8). Subsequently, the obtained SAET@ZIF-8 was characterized, and the catalytic activity, reusability and storage stability were also investigated. Results showed that the morphology of the prepared SAET@ZIF-8 nanoparticles was basically the same as that of the standard ZIF-8 materials reported in literature, and the introduction of cells did not significantly change the morphology of ZIF-8. After repeated use for 7 times, SAET@ZIF-8 could still retain 67% of the initial catalytic activity. Maintained at room temperature for 4 days, 50% of the original catalytic activity of SAET@ZIF-8 could be retained, indicating that SAET@ZIF-8 has good stability for reuse and storage. When used in the biosynthesis of Ala-Gln, the final concentration of Ala-Gln reached 62.83 mmol/L (13.65 g/L) after 30 min, the yield reached 0.455 g/(L·min), and the conversion rate relative to glutamine was 62.83%. All these results suggested that the preparation of SAET@ZIF-8 is an efficient strategy for the biosynthesis of Ala-Gln.
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Affiliation(s)
- Yingkang Zhang
- School of Biological Science, Jining Medical University, Rizhao 276800, Shandong, China
| | - Ting Cheng
- School of Biological Science, Jining Medical University, Rizhao 276800, Shandong, China
| | - Feiyang Zhao
- School of Biological Science, Jining Medical University, Rizhao 276800, Shandong, China
| | - Yanqin Yi
- School of Biological Science, Jining Medical University, Rizhao 276800, Shandong, China
| | - Qingqing Li
- School of Biological Science, Jining Medical University, Rizhao 276800, Shandong, China
| | - Zhenhua Lu
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310000, Zhejiang, China
| | - Mianbin Wu
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310000, Zhejiang, China
| | - Tao Wang
- School of Biological Science, Jining Medical University, Rizhao 276800, Shandong, China
| | - Xiaohuan Liu
- School of Biological Science, Jining Medical University, Rizhao 276800, Shandong, China
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Abe I, Tagami U, Kashiwagi T, Sugiyama M, Suzuki SI, Takagi H, Yokozeki K. Screening of α-amino acid ester acyl transferase variant with improved activity by combining rational and random mutagenesis. J Biochem 2022; 173:43-52. [PMID: 36260086 DOI: 10.1093/jb/mvac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/21/2022] [Accepted: 10/04/2022] [Indexed: 12/29/2022] Open
Abstract
Random and rational mutagenesis of an α-amino acid ester acyl transferase from Sphingobacterium siyangensis AJ2458 (SAET) was conducted to examine the production of aspartame, an α-l-aspartyl-l-phenylalanine methyl ester. We previously reported aspartame production via combination of enzymatic and chemical methods. However, the productivity of the aspartame intermediate by SAET was approximately one-fifth that of l-alanyl-l-glutamine (Ala-Gln), whose production method has already been established. Here, to improve the enzymatic activity of SAET, we performed random mutagenesis in the gene encoding SAET and obtained 10 mutations that elevated the enzymatic activity (1.2- to 1.7-fold increase) relative to that of wild-type SAET. To further improve the activity, we performed mutagenesis to optimize the combination of the obtained mutations and finally selected one SAET variant with 10 amino acid substitutions (M35-4 SAET). An Escherichia coli strain overexpressing M35-4 SAET displayed a 5.7-fold higher activity than that of the wild-type SAET, which was almost equal to that of Ala-Gln by an E. coli strain overexpressing wild-type SAET. The Vmax value of M35-4 SAET was 2.0-fold greater, and its thermostability was higher than those of wild-type SAET. These results suggest that the obtained SAET variants contribute to improvement in aspartame production.
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Affiliation(s)
- Isao Abe
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan.,Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara 630-0192, Japan
| | - Uno Tagami
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan
| | - Tatsuki Kashiwagi
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan
| | - Masakazu Sugiyama
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan
| | - Shun-Ichi Suzuki
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan
| | - Hiroshi Takagi
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara 630-0192, Japan
| | - Kenzo Yokozeki
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., Kawasaki 210-8681, Japan
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