A novel phytase characterized by thermostability and high pH tolerance from rice phyllosphere isolated Bacillus subtilis B.S.46

Recent advances in phytase thermostability engineering towards potential application in the food and feed sectors

This review comprehensively examines the advancements in engineering thermostable phytase through genetic modification and immobilization techniques, focusing on developments from the last seven years. Genetic modifications, especially protein engineering, have enhanced enzyme's thermostability and functionality. Immobilization on various supports has further increased thermostability, with 50-60 % activity retention at higher temperature (more than 50 °C). In the food industry, phytase is used in flour processing and bread making, reducing phytate content by around 70 %, thereby improving nutritional value and mineral bioavailability. In the feed industry, it serves as a poultry feed additive, breaking down phytates to enhance nutrient availability and feed efficiency. The enzyme's robustness at high temperatures makes it valuable in feed processing. The integration of microbial production of phytase with genetically engineered strains followed by carrier free immobilization represents a synergistic approach to fortify enzyme structure and improve thermal stability. These advancement in the development of phytase enzyme capable of withstanding high temperatures, thereby pivotal for industrial utilization.

Production, purification and characterization of phytase from Pichia kudriavevii FSMP-Y17and its application in layers feed

INTRODUCTION

Phytase, recognized for its ability to enhance the nutritional value of phytate-rich foods, has has gained significant prominence. The production of this enzyme has been significantly boosted while preserving economic efficiency by utilizing natural substrates and optimizing essential factors. This study focuses on optimizing phytase production through solid-state fermentation and evaluating its effectiveness in enhancing nutrient utilization in chicken diets.

OBJECTIVE

The objective is to optimize phytase production via solid-state fermentation, characterize purified phytase properties, and assess its impact on nutrient utilization in chicken diets. Through these objectives, we aim to deepen understanding of phytase's role in poultry nutrition and contribute to more efficient feed formulations for improved agricultural outcomes.

METHODOLOGY

We utilized solid-state fermentation with Pichia kudriavzevii FSMP-Y17 yeast on orange peel substrate, optimizing variables like temperature, pH, incubation time, and supplementing with glucose and ammonium sulfate. Following fermentation, we purified the phytase enzyme using standard techniques, characterizing its properties, including molecular weight, optimal temperature and pH, substrate affinity, and kinetic parameters.

RESULTS

The optimized conditions yielded a remarkable phytase yield of 7.0 U/gds. Following purification, the enzyme exhibited a molecular weight of 64 kDa and displayed optimal activity at 55 °C and pH 5.5, with kinetic parameters (Km = 3.39 × 10-3 M and a Vmax of 7.092 mM/min) indicating efficient substrate affinity.

CONCLUSION

The addition of purified phytase to chicken diets resulted in significant improvements in nutrient utilization and overall performance, including increased feed intake, improved feed conversion ratio, enhanced bird growth, better phosphorus retention, and improved egg production and quality. By addressing challenges associated with phytate-rich diets, such as reduced nutrient availability and environmental pollution, phytase utilization promotes animal welfare and sustainability in poultry production.

Biochemical characterization of purified phytase produced from Aspergillus awamori AFE1 associated with the gastrointestinal tract of longhorn beetle (Cerambycidae latreille)

The need for industrially and biotechnologically significant enzymes, such as phytase, is expanding daily as a result of the increased use of these enzymes in a variety of operations, including the manufacture of food, animal feed, and poultry feed. This study sought to characterize purified phytase from A. awamori AFE1 isolated from longhorn beetle for its prospect in industrial applications. Ammonium sulfate precipitation, ion-exchange chromatography, and gel-filtration chromatography were used to purify the crude enzyme obtained from submerged fermentation using phytase-producing media, and its physicochemical characteristics were examined. The homogenous 46.8-kDa phytase showed an 8.1-fold purification and 40.7% recovery. At 70 C and pH 7, the optimum phytase activity was noted. At acidic pH 4-6 and alkaline pH 8-10, it likewise demonstrated relative activity of 88-95% and 67-88%, respectively. It showed 67-70% residual activity between 30 and 70 C after 40 min, and 68-94% residual activity between pH 2 and 12 after 2 h. The presence of Hg+, Mg2+, and Al3+ significantly decreased the enzymatic activity, whereas Ca2+ and Cu2+ enhanced it. Ascorbic acid increased the activity of the purified enzyme, whereas ethylenediaminetetraacetic acid (EDTA) and mercaptoethanol inhibited it. The calculated values for Km and Vmax were 55.4 mM and1.99 μmol/min/mL respectively. A. awamori phytase, which was isolated from a new source, showed unique and remarkable qualities that may find use in industrial operations such as feed pelleting and food processing.

Statistical optimized production of Phytase from Hanseniaspora guilliermondii S1 and studies on purification, homology modelling and growth promotion effect

This investigation was performed to obtain a promising phytase enzyme producing yeast. In this regard, the PSM was used to isolate the phytase-producing Hanseniaspora guilliermondii S1 (MG663578) from sugarcane juice. The SSF optimum conditions for phytase generation were optimized using (OVAT) one-variable-at-a-time strategy using both Box-Behnken design and shake flask method (g/100 ml: 0.05 yeast extract, 0.15 Peptone, 0.05 malt extract 0.50 dextrose, pH 5.8 and 28ᵒC). The protein model developed was shown to be adequate for phytase production (91% accuracy), with the greatest phytase productivity in shake flask with substrate jack fruit seed powder being 395 ± 0.43 U/ml compared to 365U/ml for the BBD projected value. Crude Phytase was partially purified with a protein recovery of 43%, revealing a molecular weight of 120 kDa. It had an enzyme kinetic value of Km 3.3 mM and a Vmax of 19.1 mol/min. The 3D structure of PhyS1 amino acid sequences (PhyS1. B99990002) was simulated using Modeler 9.23, and the validated result revealed that 86.7% were in the favored region by Ramachandran plot. The SAVES server verified the 3D PDB file as satisfactory, and the model (in.pdb format) was uploaded in the PMDB database with the accession number ID: PM0082974. At the lab level, Hanseniaspora guilliermondii S1 (MG663578) producing phytase exhibited successful plant growth promotion activity in Ragi - CO 19 (Eleusine coracana L.) and Rice -Navarai - IR 64 (Oryza sativa L.). As a result, a phytase-based formulation for sustainable agriculture must be developed and tested on a large scale in diverse geographical areas of agricultural lands to determine its effect and potential on plant development.

Applied microbiology of the phyllosphere

The phyllosphere, or plant leaf surface, represents a microbial ecosystem of considerable size, holding extraordinary biodiversity and enormous potential for the discovery of new products, tools, and applications in biotechnology, agriculture, medicine, and elsewhere. This mini-review highlights the applied microbiology of the phyllosphere as an original field of study concerning itself with the genes, gene products, natural compounds, and traits that underlie phyllosphere-specific adaptations and services that have commercial and economic value for current or future innovation. Examples include plant-growth-promoting and disease-suppressive phyllobacteria, probiotics and fermented foods that support human health, as well as microbials that remedy foliar contamination with airborne pollutants, residual pesticides, or plastics. Phyllosphere microbes promote plant biomass conversion into compost, renewable energy, animal feed, or fiber. They produce foodstuffs such as thickening agents and sugar substitutes, industrial-grade biosurfactants, novel antibiotics and cancer drugs, as well as enzymes used as food additives or freezing agents. Furthermore, new developments in DNA sequence-based profiling of leaf-associated microbial communities allow for surveillance approaches in the context of food safety and security, for example, to detect enteric human pathogens on leafy greens, predict plant disease outbreaks, and intercept plant pathogens and pests on internationally traded goods. KEY POINTS: • Applied phyllosphere microbiology concerns leaf-specific adaptations for economic value • Phyllobioprospecting searches the phyllosphere microbiome for product development • Phyllobiomonitoring tracks phyllosphere microbial profiles for early risk detection.

Dephytinization of wheat and rice bran by cross-linked enzyme aggregates of Mucor indicus phytase: a viable prospect for food and feed industries

BACKGROUND

Novel feeds for improved feed intake and for enhanced nutrient bioavailability have recently attracted attention. Insoluble dietary fibers, especially rice and wheat bran, have generated much interest due to their nutritional value. Incorporating insoluble dietary fiber into diets could be a viable way to maximize the feed conversion ratio.

RESULTS

Cross-linked phytase aggregates (CLPA) were synthesized by precipitating enzymes followed by cross-linking with 5 mmol L^-1 glutaraldehyde, yielding 88.24 (U g^-1 ) of enzyme load without the assistance of a proteic feeder. The epitome of the study is the dephosphorylation of wheat bran and rice bran by varying pH, enzyme concentration, and temperature. The highest inorganic phosphorus liberation by 150 U L-^-1 of free phytase was 23.72 (wheat bran) and 48.08 mg g^-1 (rice bran) after 12 h of incubation.  Furthermore, 150 U L^-1 of CLPA liberated 28.72 (wheat bran) and 52.08 mg g^-1 (rice bran) of inorganic phosphorus with an incubation time of 12 h.

CONCLUSION

Thermostable free phytase was insolubilized to dephosphorylate the agro-residue, namely, wheat bran and rice bran, to reduce the anti-nutritional factor (the phytate content) of these insoluble dietary fibers. © 2022 Society of Chemical Industry.

Differentiate responses of soil nutrient levels and enzymatic activities to freeze-thawing cycles in different layers of moss-dominated biocrusts in a temperate desert

Introduction

The biological soil crust, a widespread phenomenon in arid and semi-arid regions, influences many ecological functions, such as soil stability, surface hydrology, and biogeochemical cycling. Global climate change has significantly altered winter and spring freeze-thaw cycles (FTCs) in mid and high-latitude deserts. However, it is unclear how these changes will affect the biological soil crust and its influence on nutrient cycling and soil enzyme activity.

Methods

We conducted this study in the Gurbantunggut Desert, a typical temperate desert, using the moss crust as an example of an evolved biological soil crust. Simulating the effects of different FTC frequencies (0, 5, and 15 times) on soil carbon, nitrogen, phosphorus-related nutrients, and extracellular enzyme activities allowed us to understand the relationship between soil environmental factors and nutrient multifunctionality during FTC changes.

Results

The results showed that recurrent FTCs significantly increased the accumulation of carbon and phosphorus nutrients in the soil and decreased the effectiveness of nitrogen nutrients. These changes gradually stabilized after 15 FTCs, with available nutrients showing greater sensitivity than the previous full nutrient level. FTCs inhibited carbon, nitrogen, and phosphorus cycle-related hydrolase activities and promoted carbon cycle-related oxidase activities in the crust layer. However, in the 0-3 cm layer, the carbon and phosphorus cycle-related hydrolase activities increased, while peroxidase and urease activities decreased. Overall, the nutrient contents and enzyme activities associated with the carbon, nitrogen, and phosphorus cycles were lower in the 0-3 cm layer than in the crust layer. In addition, the multifunctionality of nutrients in the soil decreased after 15 FTCs in the crust layer and increased after 5 FTCs in the 0-3 cm layer. Structural equation modeling showed that FTC, soil water content, pH, available nutrients, and extracellular enzyme activity had opposite effects on nutrient multifunctionality in different soil layers. The change in nutrient multifunctionality in the crust layer was primarily caused by changes in total nutrients, while soil water content played a greater role in the 0-3 cm layer. Regardless of the soil layer, the contribution of total nutrients was much higher than the contribution of available nutrients and extracellular enzyme activity. In conclusion, it is essential to consider different soil layers when studying the effects of global climate change on the nutrient cycling of the biological soil crust.

Research status of Bacillus phytase

Phytic acid is abundant in seeds, roots and stems of plants, it acts as an anti-nutrient in food and feed industry, since it affects the absorption of nutrients by humans and monogastric animals. Furthermore, phosphorus produced through its decomposition by microorganisms can cause environmental pollution. Phytase degrades phytic acid generating precursors of inositol that can be used in clinical practice; in addition, phytase treatment can minimize the anti-nutritional effect of phytic acid. The use of phytase synthesized from Bacillus is more advantageous due to its high activity. Additionally, its good heat resistance under neutral conditions greatly fills the gap of commercial utilization of acid phytase. In this review, we summarize the latest research results on Bacillus phytase, including its physiological and biochemical characteristics, molecular structure information, calcium effects on its catalytic activity and stability, its catalytic mechanism and molecular modification.

Bioprocessing of Agricultural Residues as Substrates and Optimal Conditions for Phytase Production of Chestnut Mushroom, Pholiota adiposa, in Solid State Fermentation

Phytase is an enzyme that breaks down phytates to release phosphorus in an available form. This enzyme plays an important role in animals, especially monogastric animals. It serves to improve phytate digestion along with phosphorus absorption, which are required for optimal growth performance and health. In this study, five mushroom species (Amauroderma rugosum SDBR-CMU-A83, Ganoderma mastoporum SDBR-CMU-NK0244, Marusmius sp.1 SDBR-CMU-NK0215, Pholiota adiposa SDBR-CMU-R32 and Piptoporellus triqueter SDBR-CMU-P234) out of 27 mushroom species displayed positive phytase production by agar plate assay. Consequently, these five mushroom species were selected for determination of their potential ability to produce phytase under solid-state fermentation using five agricultural residues (coffee parchment, oil palm empty fruit bunches, rice bran, sawdust, and water hyacinth) as substrates. The highest yield of phytase production (17.02 ± 0.92 units/gram dry substrate) was obtained after one week of fermentation. Optimization for phytase production was determined by statistical approaches using a Plackett-Burman design to screen ten parameters of relevant substrate components. Two significant parameters, the amount of water hyacinth and the moisture content, were found to affect the production process of phytase. Furthermore, the optimal temperature, pH value, and fermentation period were evaluated. The results indicated that the highest degree of phytase production at 53.66 ± 1.68 units/gram dry substrate (3.15-fold increase) was obtained in water hyacinth containing 85% moisture content by addition with a suitable basal liquid medium at a pH value of 6.5 after being incubated at 30 °C for seven days. The crude phytase of P. adiposa was precipitated and the precipitated extract was then used to determine partial characterizations. The precipitated extract displayed high activities after exposure to conditions of 42 °C and pH 5.0. Furthermore, Fe²⁺ enhanced phytase activity and precipitated extract displayed the best stability at a pH value of 8.0 and a temperature of 4 °C.

Beneficial features of plant growth-promoting rhizobacteria for improving plant growth and health in challenging conditions: A methodical review

New eco-friendly approaches are required to improve plant biomass production. Beneficial plant growth-promoting (PGP) bacteria may be exploited as excellent and efficient biotechnological tools to improve plant growth in various - including stressful - environments. We present an overview of bacterial mechanisms which contribute to plant health, growth, and development. Plant growth promoting rhizobacteria (PGPR) can interact with plants directly by increasing the availability of essential nutrients (e.g. nitrogen, phosphorus, iron), production and regulation of compounds involved in plant growth (e.g. phytohormones), and stress hormonal status (e.g. ethylene levels by ACC-deaminase). They can also indirectly affect plants by protecting them against diseases via competition with pathogens for highly limited nutrients, biocontrol of pathogens through production of aseptic-activity compounds, synthesis of fungal cell wall lysing enzymes, and induction of systemic responses in host plants. The potential of PGPR to facilitate plant growth is of fundamental importance, especially in case of abiotic stress, where bacteria can support plant fitness, stress tolerance, and/or even assist in remediation of pollutants. Providing additional evidence and better understanding of bacterial traits underlying plant growth-promotion can inspire and stir up the development of innovative solutions exploiting PGPR in times of highly variable environmental and climatological conditions.

Probiotic Validation of a Non-native, Thermostable, Phytase-Producing Bacterium: Streptococcus thermophilus

Phytate-linked nutritional deficiency disorders have plagued poultry for centuries. The application of exogenous phytases in poultry feed has served as a solution to this problem. However, they are linked to certain limitations which include thermal instability during prolonged feed processing. Therefore, in this study, Streptococcus thermophilus 2412 based phytase stability was assessed at higher temperatures up to 90 °C. This was followed by probiotic validation of the same bacterium in an in vitro intestinal model. Bacterial phytase showed thermostability up to 70 °C with a recorded activity of 9.90 U. The bacterium was viable in the intestinal lumen as indicated by the cell count of 6.10 log(CFU/mL) after 16 h. It also showed acid tolerance with a stable cell count of 5.01 log(CFU/mL) after 16 h of incubation at pH 2. The bacterium displayed bile tolerance yielding a cell count of 6.36 log(CFU/mL) in the presence of 0.3% bile. Bacterial susceptibility was observed toward all tested antibiotics with a maximum zone of 20 mm against clindamycin. The maximum antagonistic activity was observed against Staphylococcus aureus, Serratia marcescens, and Escherichia coli with inhibition zone diameters up to 10 mm. The above characteristics prove that S. thermophilus 2412 can be used as an effective phytase-producing poultry probiotic.

An in vitro chicken gut model for the assessment of phytase producing bacteria

An in vitro simulated chicken gut model was proposed for studying the phytase activity of selected bacteria such as Streptococcus thermophilus, Sporosarcina pasteurii, Sporosarcina globispora, and Sporosarcina psychrophila using known probiotic bacterium, Lactobacillus helveticus as a control. The selected bacteria were viable in the intestinal lumen and produced extracellular phytase at optimal phytate concentration of 6.25 mM when compared to 3.125 mM and 12.5 mM. These bacteria demonstrated significantly higher (p < 0.05) phosphate liberation (up to 387 µM) due to better phytase activity in the production medium, when compared to the growth medium (339 µM). The phytase activity showed a steady increase in phosphate liberation up to 150 min after which it became constant. This trend is observed for the selected bacteria at pH 5, 6 and 7. However, the liberation of phosphates showed no significant difference (p > 0.05) at the tested pH. Among the analyzed bacteria, the members of the genus Sporosarcina showed better phytate degradation when compared to S. thermophilus. The proposed model can be extended to analyze any extracellular enzymes produced by gut microbes.

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.

Microbial degradation of myo-inositol hexakisphosphate (IP6): specificity, kinetics, and simulation

Microbial degradation of myo-inositol hexakisphosphate (IP6) is crucial to deal with nutritional problems in monogastric animals as well as to prevent environmental phosphate pollution. The present study deals with the degradation of IP6 by microorganisms such as Sporosarcina spp. pasteurii, globiospora, psychrophila, Streptococcus thermophilus and Saccharomyces boulardii. These microbes were screened for phytase production under laboratory conditions. The specificity of the enzyme was tested for various phosphorylated substrates such as sodium phytate (IP6), sodium hexametaphosphate, phenyl phosphate, α-d-glucose-6 phosphate, inosine 5' monophosphate and pyridoxal 5' phosphate. These enzymes were highly specific to IP6. The influence of modulators such as phytochemicals and metal ions on the enzymatic activity was assessed. These modulators in different concentrations had varying effect on microbial phytases. Calcium (in optimal concentration of 0.5 M) played an important role in enzyme activation. The enzymes were then characterized based on their molecular weight 41~43 kDa. The phytase-producing microbes were assessed for IP6 degradation in a simulated intestinal setup. Among the selected microbes, Sporosarcina globiospora hydrolyzed IP6 effectively, as confirmed by colorimetric time-based analysis.

New Bacterial Phytase through Metagenomic Prospection

Alkaline phytases from uncultured microorganisms, which hydrolyze phytate to less phosphorylated myo-inositols and inorganic phosphate, have great potential as additives in agricultural industry. The development of metagenomics has stemmed from the ineluctable evidence that as-yet-uncultured microorganisms represent the vast majority of organisms in most environments on earth. In this study, a gene encoding a phytase was cloned from red rice crop residues and castor bean cake using a metagenomics strategy. The amino acid identity between this gene and its closest published counterparts is lower than 60%. The phytase was named PhyRC001 and was biochemically characterized. This recombinant protein showed activity on sodium phytate, indicating that PhyRC001 is a hydrolase enzyme. The enzymatic activity was optimal at a pH of 7.0 and at a temperature of 35 °C. β-propeller phytases possess great potential as feed additives because they are the only type of phytase with high activity at neutral pH. Therefore, to explore and exploit the underlying mechanism for β-propeller phytase functions could be of great benefit to biotechnology.

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.

Valorisation of untreated cane molasses for enhanced phytase production by Bacillus subtilis K46b and its potential role in dephytinisation

BACKGROUND

The high cost of phytase production is the most limiting factor in its application in animal feeds. The present study aimed to develop a low-cost medium for production of a novel phytase in submerged fermentation using inexpensive agro-industrial by-products. The applicability of phytase in dephytinisation of commonly used food/feed ingredients, i.e. soybean meal and wheat bran, was also investigated.

RESULTS

Using a one-factor-at-a-time approach, soybean meal and cane molasses were identified as significant agro-industrial by-products and these factors were subsequently optimised using response surface methodology (RSM). A central composite design was employed to further enhance phytase yield. Under optimum conditions of soybean meal 22.3 g L-1 , cane molasses 100 g L-1 and 39 h fermentation, phytase production increased to 56.562 U mL-1 , indicating more than 28-fold enhancement. The enzyme efficiently dephytinised wheat bran and soybean meal after 24 h incubation at 56.5 °C and increased inorganic phosphate content by 240% and 155%, respectively.

CONCLUSION

Soybean meal and cane molasses were successfully used for enhancement of phytase production as economical carbon, nitrogen and phytic acid sources using RSM. The phytase showed a good capability to dephytinise wheat bran and soybean meal, demonstrating that the enzyme can be considered as a potential candidate for industrial food and feed applications. © 2016 Society of Chemical Industry.