Prediction of substrate-binding site and elucidation of catalytic residue of a phytase from Bacillus sp

Assessment of Recombinant β-Propeller Phytase of the Bacillus Species Expressed Intracellularly in Yarrowia lipolityca

Phytases of the PhyD class according to their pH optimum (7.0-7.8) and high thermal stability can claim to be used in the production of feed supplements. However, today they have no practical application in feed production because there are no suitable producers sufficient for its biotechnological production compared to the PhyA and PhyC class ones. Moreover, in most cases, the technologies with the enzymes produced in secretory form are preferable for the production of phytases, though upon microencapsulation in yeast-producing cells, the phytase thermal stability increases significantly compared to the extracellular form, which improves its compatibility with spray drying technology. In this study, we assayed the intracellular heterologous expression of PhyD phytase from Bacillus species in the Yarrowia lipolytica yeast cells. While the technology has been successfully used to synthesize PhyC phytase from Obesumbacterium proteus, PhyD phytase tends to aggregate upon intracellular accumulation. Furthermore, we evaluated the prospects for the production of encapsulated phytase of the PhyD class of high enzymatic activity when it accumulates in the cell cytoplasm of the Y. lipolytica extremophile yeast, a highly effective platform for the production of recombinant proteins.

Microbial phytase: Impact of advances in genetic engineering in revolutionizing its properties and applications

Phytases are enzymes that increase the availability of phosphorous in monogastric diet and reduces the anti-nutrition effect of phytate. This review highlights contributions of recombinant technology to phytase research during the last decade with specific emphasis on new generation phytases. Application of modern molecular tools and genetic engineering have aided the discovery of novel phytase genes, facilitated its commercial production and expanded its applications. In future, by adopting most recent gene improvement techniques, more efficient next generation phytases can be developed for specific applications.

β-Propeller phytases: Diversity, catalytic attributes, current developments and potential biotechnological applications

Phytases are phosphatases which stepwise remove phosphates from phytic acid or its salts. β-Propeller phytase (BPPhy) belongs to a special class of microbial phytases that is regarded as most diverse, isolated and characterized from different microbes, mainly from Bacillus spp. BPPhy class is unique for its Ca²⁺-dependent catalytic activity, strict substrate specificity, active at neutral to alkaline pH and high thermostability. Numerous sequence and structure based studies have revealed unique attributes and catalytic properties of this class, as compared to other classes of phytases. Recent studies including cloning and expression and genetic engineering approaches have led to improvements in BPPhy which provide an opportunity for extended utilization of this class of phytases in improving animal nutrition, human health, plant growth promotion, and environmental protection, etc. This review describes the sources and diversity of BPPhy genes, biochemical properties, Ca²⁺ dependence, current developments in structural elucidation, heterogeneous expression and catalytic improvements, and multifarious applications of BPPhy.

Structural Characteristics and Catalytic Mechanism of Bacillus β-Propeller Phytases

β-Propeller phytases of Bacillus are unique highly conservative and highly specific enzymes capable of cleaving insoluble phytate compounds. In this review, we analyzed data on the properties of these enzymes, their differences from other phytases, and their unique spatial structures and substrate specificities. We considered influences of different factors on the catalytic activity and thermostability of these enzymes. There are few data on the hydrolysis mechanism of these enzymes, which makes it difficult to analyze their mechanism of action and their final products. We analyzed the available data on hydrolysis by β-propeller phytases of calcium complexes with myo-inositol hexakisphosphate.

Characteristics and Applicability of Phytase of the Yeast Pichia anomala in Synthesizing Haloperoxidase

The phytase of the yeast Pichia anomala is a histidine acid phosphatase based on signature sequences and catalytic amino acids identified by site-directed mutagenesis. Among modulators, N-bromosuccinimide and butanedione inhibit phytase, while Ca(2+) and Ni(2+) stimulate slightly. Vanadate exhibits competitive inhibition of phytase, making it bifunctional to act as haloperoxidase. Molecular docking supports vanadate to share its binding site with phytate. The T 1/2, activation energy (E a ), temperature quotient (Q 10), activation energy of thermal inactivation (Ed), and enthalpy (ΔH d (0) ) of the enzyme are 4.0 min (80 °C), 27.72 kJ mol(-1), 2.1, 410.62 kJ mol(-1), and ∼407.8 kJ mol(-1) (65-80 °C), respectively. The free energy of the process (ΔG d (o) ) increases from 49.56 to 71.58 kJ mol(-1) with rise in temperature, while entropy of inactivation (ΔS d (0) ) remains constant at ∼1.36 kJ mol(-1) K(-1). The supplementation of whole wheat dough with rPPHY resulted in 72.5 % reduction in phytic acid content of bread. These characteristics confirm that the phytase has adequate thermostability for its applicability as a food and feed additive.