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Liu ZQ, Lu MM, Zhang XH, Cheng F, Xu JM, Xue YP, Jin LQ, Wang YS, Zheng YG. Significant improvement of the nitrilase activity by semi-rational protein engineering and its application in the production of iminodiacetic acid. Int J Biol Macromol 2018; 116:563-571. [PMID: 29753012 DOI: 10.1016/j.ijbiomac.2018.05.045] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [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: 12/22/2017] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 01/09/2023]
Abstract
Iminodiacetic acid (IDA) is widely used as an intermediate in the manufacturing of chelating agents, glyphosate herbicides and surfactants. To improve activity and tolerance to the substrate for IDA production, Acidovorax facilis nitrilase was selected for further modification by the gene site saturation mutagenesis method. After screened by a two-step screening method, the best mutant (Mut-F168V/T201N/S192F/M191T/F192S) was selected. Compared to the wild-type nitrilase, Mut-F168V/T201N/S192F/M191T/F192S showed 136% improvement in specific activity. Co2+ stimulated nitrilase activity, whereas Cu2+, Zn2+ and Tween 80 showed a strong inhibitory effect. The Vmax and kcat of Mut-F168V/T201N/S192F/M191T/F192S were enhanced 1.23 and 1.23-fold, while the Km was decreased 1.53-fold. The yield of Mut-F168V/T201N/S192F/M191T/F192S with 453.2 mM of IDA reached 71.9% in 5 h when 630 mM iminodiacetonitrile was used as substrate. This study indicated that mutant nitrilase obtained in this study is promising in applications for the upscale production of IDAN.
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Affiliation(s)
- Zhi-Qiang Liu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Ming-Ming Lu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Xin-Hong Zhang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China; Department of Biological and Environmental Engineering, Hefei University, Hefei 230601, China
| | - Feng Cheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jian-Miao Xu
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Ya-Ping Xue
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Li-Qun Jin
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Yuan-Shan Wang
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China
| | - Yu-Guo Zheng
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
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Muluka H, Sheelu G, Nageshwar YV. Bioconversion of Iminodiacetonitrile to Iminodiacetic acid with whole cells of Lysinibacillus boronitolerans MTCC 107614 (IICT-akl252). Bioprocess Biosyst Eng 2016; 39:413-20. [PMID: 26742952 DOI: 10.1007/s00449-015-1524-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 12/11/2015] [Indexed: 10/22/2022]
Abstract
Biotechnological potential of nitrilases are prompting significant interest in finding the novel microbes capable of hydrolyzing nitriles. In this view, we have screened about 450 bacterial strains for nitrilase production using bioconversion of iminodiacetonitrile (IDAN) to iminodiacetic acid (IDA) through hydrolysis and obtained six nitrilase-producing isolates. Among these six isolates, IICT-akl252 was promising which was identified as Lysinibacillus boronitolerans. This is the first report on L. boronitolerans for nitrilase activity. Optimization of various medium and reaction parameters for maximizing the nitrilase production using whole cells in shake flask was carried out for L. boronitolerans IICT-akl252. Sucrose (2 %) as a carbon source attained better nitrilase yield while IDAN appeared to be the preferable inducer (0.2 %). The maximum IDA formation was achieved with 100 mM IDAN and 150 mg/ml cells at 30 °C and pH 6.5. After optimization of the culture and reaction conditions, the activity of nitrilase was increased by 2.3-fold from 27.2 to 64.5 U. The enzyme was stable up to 1 h at 50 °C. The enzyme was able to hydrolyze aliphatic, aromatic and heterocyclic nitrile substrates.
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