Nitrilase: a promising biocatalyst in industrial applications for green chemistry

Purification and Characterization of Nitphym, a Robust Thermostable Nitrilase From Paraburkholderia phymatum

“…Its high oligomericity of more than 18 subunits is in accordance with many described nitrilases, the preferred native forms of nitrilases seem to be large aggregates of 6-26 units (Banerjee et al, 2002). Its optimum temperature of approximately 45-55 • C is slightly higher than optima reported for many nitrilases from mesophilic organisms (Shen et al, 2021), usually ranging from 30-50 • C, such as the one of its close homolog from Rhodobacter sphaeroides (Table 2, Uniprot ID: G5DDB2) (71% of protein sequence identity with Nit phym ) described to convert also both aromatic and aliphatic nitriles (Wang et al, 2014), or the commerciaized nitrilase from Arabidopsis thaliana What is remarkable for a nitrilase from a mesophilic organism is the low effect of temperature on its stability. The stability of Nit phym at 30 • C for more than 2 days of incubation is much greater than for other nitrilases with comparable optimal temperature between 40 • C and 50 • C that generally exhibited a half-life of less than 20 h at 30 • C. For example, the well described nitrilase from Pseudomonas fluorescens strain EBC191 has similar temperature profile (optima temperature: 45-55 • C) but is much more unstable than Nit phym at these temperatures with activity decreasing within 30 min above 40 • C (Table 2; Kiziak et al, 2005).…”

“…They are “easy” enzymes that do not require any cofactor or metal ions; thus, biocatalytical hydrolysis carried out by nitrilases tends to be preferred over chemical methods due to their efficiency and relative ecological friendliness ( Singh et al, 2006 ; Gong et al, 2012 ; Nigam et al, 2017 ; Bhalla et al, 2018 ). This last decade, they have been successfully developed to facilitate the production of chemicals ( Shen et al, 2021 ), such as acrylic acid ( Nagasawa et al, 1990 ) and ( R )-(-) mandelic acid ( Fan et al, 2017b ). Moreover, nitrilases have also found application in the surface modification of acrylic fibers in the textile industry ( Matama et al, 2007 ) and in industrial bioremediation processes, such as degradation of the highly toxic 2,6-dichloro-benzonitrile and bromoxynil (3,5-dibromo-4 hydroxybenzonitrile) present in wastewater ( Mueller et al, 2006 ; Nigam et al, 2017 ; Park et al, 2017 ).…”

Genome Mining, Phylogenetic and Structural Analysis of Bacterial Nitrilases for the Biodegradation of Nitrile Compounds

“…The domain analysis of nitrilases AcNit, As7Nit, Cn5Nit and Cn9Nit revealed a conserved catalytic domain (Shen et al, 2020). Further characterization of these four nitrilases revealed presence of single motif consisted of 28 aa although the position is variable among all (Table 3; Fig.…”

“…Similarly, aromatic nitrile substrates are stabilized by involving W170 and F202 and other residues PGSMVGQIF are responsible for making substrate-binding loop (Zhang et al, 2014;Raczynska et al, 2011). Previous studies have also revealed formation of oxyanion hole by involving phenylalanine which play major role in recognizing substrates (Shen et al, 2020). Therefore, the selected nitrilase AcNit contain catalytic C158 which acts as a nucleophile, E40 activates the sulfhydryl group of C158 by acting as a base, and K113 stabilizes intermediates formed in the reaction.…”

“…In additions, the nitrilases are also of particular interest due to their potential use in food additives (Tang et al, 2019), surface modi cation of polyacrylonitrile (PAN) bers (Zhua et al, 2013), pharmaceutical and agrochemicals sectors (Zhang et al, 2019), degradation of bromoxynil, ioxynil, acrylonitrile (Shen et al, 2020) contaminated waste bodies such as near to gold mining, electroplating industries and production of indole acetic acid (IAA) from tryptophan (Salwan et al, 2020). Since, microbial nitrilases can transform different nitriles into their carboxylic acids or amides therefore, have immense biotechnological applications in the detoxi cation of nitriles, cyanide and for the biosynthesis of plant growth regulators (Rucka et al With the advent of genome and metagenome sequencing, presently over 5000 nitrilase encoding genes have been deposited in the GenBank database (Shen et al, 2020). Despite the initial reports on nitrilases from plants, several nitrilases have been characterized from bacteria and fungi (Thimann and Mahadevan, 1964;Hook and Robinson, 1964;Gong et al, 2012).…”