Bioengineering of Nitrilases Towards Its Use as Green Catalyst: Applications and Perspectives

Abstract

Nitrilases are commercial biocatalysts used for the synthesis of plastics, paints, fibers in the chemical industries, pharmaceutical drugs and herbicides for agricultural uses. Nitrilase hydrolyses the nitriles and dinitriles to their corresponding carboxylic acids and ammonia. They have a broad range of substrate specificities as well as enantio-, regio- and chemo-selective properties which make them useful for biotransformation of nitriles to important compounds because of which they are considered as 'Green Catalysts'. Nitriles are widespread in nature and synthesized as a consequence of anthropogenic and biological activities. These are also present in certain plant species and are known to cause environmental pollution. Biotransformation using native organisms as catalysts tends to be insufficient since the enzyme of interest has very low amount in the total cellular protein, rate of reaction is slow along with the instability of enzymes. Therefore, to overcome these limitations, bioengineering offers an alternative approach to alter the properties of enzymes to enhance the applicability and stability. The present review highlights the aspects of producing the recombinant microorganisms and overexpressing the enzyme of interest for the enhanced stability at high temperatures, immobilization techniques, extremes of pH, organic solvents and hydrolysing dintriles to chiral compounds which may enhance the possibilities for creating specific enzymes for biotransformation.

Rolling circle amplification of synthetic DNA accelerates biocatalytic determination of enzyme activity relative to conventional methods

“…The observed discordance in Nit1 activity between cell-based and CFPS expression is unclear and warrants further investigation into possible inhibitory substances from the CFPS reaction, or perhaps lack of enzyme post-translational modification or accessory proteins that might be critical for this under-studied enzyme. For all other positive enzyme "hits, " the substrate patterns that emerged from our comparative analysis revealed similar nitrilase taxonomies 21 (Fig. 5).…”

Deep Hypersaline Anoxic Basins as Untapped Reservoir of Polyextremophilic Prokaryotes of Biotechnological Interest

“…Moreover, nitrilases can detoxify cyanide present within wastes and degrade herbicides, representing an enzyme of extreme importance in bioremediation [243]. Biotransformation using native organisms as catalysts tends to be insufficient because the amount of nitrilases present as total cellular proteins is very low, and the reaction rate is slow and unstable [244]. Thus, the nitrilase recently identified by metagenomes mining in the Atlantis II DHAB could represent a valuable alternative not only for its thermal stability and tolerance to heavy metals compared to closely related nitrilases but also for the great number of microorganisms which could possess and produce these enzymes [211].…”

Rhodococcus as a Versatile Biocatalyst in Organic Synthesis

“…It is worth mentioning that even though only a small number of nitrilase-catalyzed reactions with Rhodococcus have been described, this nitrile-degrading enzyme class in general is well-studied and applied in a multitude of reactions, which can be followed-up on in several comprehensive reviews and books [114,189,190,191].…”