Thermostable phytase in feed and fuel industries

Phytase with wide ranging biochemical properties has long been utilized in a multitude of industries, even so, thermostability plays a crucial factor in choosing the right phytase in a few of the sectors. Mesophilic phytases are not considered to be a viable option in the feed industry owing to its limited stability in the required feed processing temperature. In the recent past, inclusion of thermostable phytase in fuel ethanol production from starch based raw material has been demonstrated with economic benefits. Therefore, considerable emphasis has been placed on using complementary approaches such as mining of extremophilic microbial wealth, encapsulation and using enzyme engineering for obtaining stable phytase variants. This article means to give an insight on role of thermostable phytases in feed and fuel industries and methods for its development, highlighting molecular determinants of thermostability.

Mining of Ruminant Microbial Phytase (RPHY1) from Metagenomic Data of Mehsani Buffalo Breed: Identification, Gene Cloning, and Characterization

Phytases have been widely used as animal feed supplements to increase the availability of digestible phosphorus, especially in monogastric animals fed cereal grains. The present study describes the identification of a full-length phytase gene of <i>Prevotella</i> species present in Mehsani buffalo rumen. The gene, designated as RPHY1, consists of 1,251 bp and is expressed into protein with 417 amino acids. A homology search of the deduced amino acid sequence of the RPHY1 phytase gene in a nonredundant protein database showed that it shares 92% similarity with the histidine acid phosphatase domain. Subsequently, the RPHY1 gene was expressed using a pET32a expression vector in <i>Escherichia coli </i>BL21 and purified using a His60 Ni-NTA gravity column. The mass of the purified RPHY1 was estimated to be approximately 63 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimal RPHY1 enzyme activity was observed at 55°C (pH 5) and exhibited good stability at 5°C and within the acidic pH range. Significant inhibition of RPHY1 activity was observed for Mg²⁺ and K⁺ metal ions, while Ca²⁺, Mn²⁺, and Na⁺ slightly inhibited enzyme activity. The RPHY1 phytase was susceptible to SDS, and it was highly stimulated in the presence of EDTA. Overall, the observed comparatively high enzyme activity levels and characteristics of the RPHY1 gene mined from rumen prove its promising candidature as a feed supplement enzyme in animal farming.

In vitro engineering of microbial enzymes with multifarious applications: prospects and perspectives

The discovery of a novel enzyme from a microbial source takes anywhere between months to years, and therefore, there has been an immense interest in modifying the existing microbial enzymes to suit the present day needs of the industry. The redesigning of industrially useful enzymes for improving their performance has become a challenge because bioinformatics databases have been revealing new facts on a day-to-day basis. Modification of the existing enzymes has become a trend for fine tuning of biocatalysts in the biotech industry. Hydrolases are employed in pharmaceutical, biofuel, detergent, food and feed industries that significantly contribute to the global annual revenue, and therefore, the emphasis has been on engineering them. Although a large data is accumulating on making alterations in microbial enzymes, there is a lack of definite information on redesigning industrial enzymes. This review focuses on the recent developments in improving the characteristics of various biotechnologically important enzymes.