Biotransformation of 4-hydroxyphenylacetonitrile to 4-hydroxyphenylacetic acid using whole cell arylacetonitrilase of Alcaligenes faecalis MTCC 12629. (October 2018)

• Record Type: Journal Article
• Authors: Thakur, Neerja; Kumar, Vijay; Thakur, Shikha; Sharma, Nikhil; Sheetal, ; Bhalla, Tek Chand
• Is Part Of: Process biochemistry. Volume 73(2018)
• Page Start: 117
• Page End: 123
• Publication Date: 2018-10
• Subjects: Nitrilase -- Bioprocess -- 4-Hydroxyphenylacetic acid; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2018.07.012
• Languages: English
• ISSNs: 1359-5113

Abstract

Graphical abstract: Highlights: Hyperinduction of nitrilase by inducer feeding approach. Nitrilase mediated biotransformation of 4-hydroxyphenylacetonitrile. Bioprocess development for 4-hydroxyphenylacetic acid synthesis. Fed batch synthesis at 500 ml scale. Abstract: The whole cell arylacetonitrilase of Alcaligenes faecalis MTCC 12629 was employed to develop a bioprocess for the synthesis of 4-hydroxyphenylacetic acid (4-HPAA) from 4-hydroxyphenylacetonitrile (4-HPAN). Isobutyronitrile emerged as the most appropriate inducer with a 1.2-fold enhanced nitrilase production in inducer feeding approach. A. faecalis MTCC 12629 nitrilase preferably hydrolyzed 4-HPAN, 4-aminoyphenylacetonitrile, mandelonitrile and phenylacetonitrile to their corresponding acids. Thermostability profile revealed the stability of nitrilase at 40, 45 and 50°C with the half-life of 45 h, 36 h and 13 h, respectively. Michaelis constant ( K m ) and reaction velocity ( V max ) of nitrilase were calculated as 20 mM and 2 U/mg dcw, respectively. This nitrilase exhibited complete conversion of 4-HPAN to 4-HPAA at 45°C in 50 mM K2 HPO4 /KH2 PO4 buffer (pH 7.0) in 30 min. A fed batch process designed at 500 ml with five feedings of substrate resulted in 150 mM product formation using 18 U/ml whole cells nitrilase (16 mg/ml dcw) at 45°C. This is the first report on the production of 4-HPAA through nitrilase mediated pathway with the volumetric and catalytic productivity of 23 g/l and 4.13 g/g dcw/h, respectively.