Phytase-producing Bacillus sp. inoculation increases phosphorus availability in cattle manure

Organic wastes rich in phosphorus (P) are considered an alternative to decrease the dependence on chemical P fertilization in crops and pastures. Microbial inoculants are being studied as a tool to increase plant P availability in organic wastes. In this study, we explore the effect of inoculation with Bacillus sp. MQH-19 (a native phytase-producing bacterium) on the release of inorganic phosphorus (Pi) in cattle manure with low available P but a high total P content. Bacteria inoculation resulted in a higher release of Pi (8% in NaHCÜ3 and 13% in NaOH-EDTA extracts) compared with that of uninoculated manure (0.7% in NaHCÜ3 and 0.1% in NaOH-EDTA extracts). However, a greater amount of Pi was released in inoculated manure supplemented with phytate (47% in NaHCÜ3 and 117% in NaOH-EDTA extracts) compared with that of uninoculated manure supplemented with phytate (30% in NaHCÜ3 and 15% in NaOH-EDTA extracts). In addition, the use of denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) revealed that the bacterial community structure in manure was affected by inoculation and that the prevalence of Bacillus sp. MQH-19 decreased during incubation (6 days). This study demonstrates that Pi availability in cattle manure can be increased by phytase-producing bacteria inoculation. Phytase-producing bacteria inoculation might represent an attractive strategy to increase P availability in agricultural wastes, which are used as organic fertilizers in crops and pastures

A holistic approach to understanding the desorption of phosphorus in soils

The mobility and resupply of inorganic phosphorus (P) from the solid phase were studied in 32 soils from the UK. The combined use of diffusive gradients in thin films (DGT), diffusive equilibration in thin films (DET) and the “DGT-induced fluxes in sediments” model (DIFS) were adapted to explore the basic principles of solid-to-solution P desorption kinetics in previously unattainable detail. On average across soil types, the response time (Tc) was 3.6 h, the desorption rate constant (k–1) was 0.0046 h–1, and the desorption rate was 4.71 nmol l–1 s–1. While the relative DGT-induced inorganic P flux responses in the first hour is mainly a function of soil water retention and % Corg, at longer times it is a function of the P resupply from the soil solid phase. Desorption rates and resupply from solid phase were fundamentally influenced by P status as reflected by their high correlation with P concentration in FeO strips, Olsen, NaOH–EDTA and water extracts. Soil pH and particle size distribution showed no significant correlation with the evaluated mobility and resupply parameters. The DGT and DET techniques, along with the DIFS model, were considered accurate and practical tools for studying parameters related to soil P desorption kinetics

Linking the depletion of rhizosphere phosphorus to the heterologous expression of a fungal phytase in Nicotiana tabacum as revealed by enzyme-labile P and solution 31P NMR spectroscopy

Root exudation of phytase could improve the ability of plants to access organic forms of soil phosphorus (P), thereby minimizing fertilizer requirements and improving P use efficiency in agroecosystems. After 75 days growth in a high available P soil, shoot biomass and P accumulation, soil pH, and rhizosphere P depletion were investigated in Nicotiana tabacum wild-type and transgenic plant-lines expressing and exuding Aspergillus niger phytase (ex::phyA), or a null-vector control. Solution 31P NMR analysis revealed a 7% to 11% increase in orthophosphate and a comparable depletion of undefined monoester P compounds (-13 to -18%) in the rhizosphere of tobacco plants relative to the unplanted soil control. Wild-type plants had the greatest impact on the composition of rhizosphere P based on the depletion of other monoester P, polyphosphate, and phosphonate species. The depletion of phytase-labile P by ex::phyA plants was associated with decreased proportions of other monoester P, rather than myo-InsP6 as expected. Rhizosphere pH increased from 6.0 to 6.5–6.7 in transgenic plant soils, beyond the pH optimum for A. niger phyA activity (pH=5), and may explain the limited specificity of ex::phyA plants for phytate in this soil. The efficacy of single exudation traits (e.g., phytase) therefore appear to be limited in P-replete soil conditions and may be improved where soil pH matches the functional requirements of the enzyme or trait of interest

Response-based selection of barley cultivars and legume species for complementarity:root morphology and exudation in relation to nutrient source

Phosphorus (P) and nitrogen (N) use efficiency may be improved through increased biodiversity in agroecosystems. Phenotypic variation in plants’ response to nutrient deficiency may influence positive complementarity in intercropping systems. A multicomponent screening approach was used to assess the influence of P supply and N source on the phenotypic plasticity of nutrient foraging traits in barley (H. vulgare L.) and legume species. Root morphology and exudation were determined in six plant nutrient treatments. A clear divergence in the response of barley and legumes to the nutrient treatments was observed. Root morphology varied most among legumes, whereas exudate citrate and phytase activity were most variable in barley. Changes in root morphology were minimized in plants provided with ammonium in comparison to nitrate but increased under P deficiency. Exudate phytase activity and pH varied with legume species, whereas citrate efflux, specific root length, and root diameter lengths were more variable among barley cultivars. Three legume species and four barley cultivars were identified as the most responsive to P deficiency and the most contrasting of the cultivars and species tested. Phenotypic response to nutrient availability may be a promising approach for the selection of plant combinations for minimal input cropping systems

Bacterial Communities Associated with the Cycling of Non-Starch Polysaccharides and Phytate in Aquaponics Systems

Aquaponics are efficient systems that associate aquatic organisms’ production and plants by recirculating water and nutrients between aquaculture and hydroponic tanks. In this study, we characterised the bacterial communities in the freshwater aquaponics system that can mineralise polysaccharides and phytate by producing carbohydrate-degrading enzymes and phytases, by 16S rRNA gene sequencing and in vitro culture techniques. Around 20% of the operational taxonomic units (zOTUs) identified were previously reported to carry fibre-degrading enzyme putative genes, namely β-glucanase (1%), xylanase (5%), or cellulases (17%). Ten % of the zOTUs were previously reported to carry putative genes of phytases with different catalytic mechanisms, namely β-propeller (6%), histidine acid phytases (3%), and protein tyrosine phytase (<1%). Thirty-eight morphologically different bacteria were isolated from biofilms accumulated in fish and plant compartments, and identified to belong to the Bacilli class. Among these, 7 could produce xylanase, 8 produced β-glucanase, 14 produced cellulase, and 11 isolates could secrete amylases. In addition, Staphylococcus sp. and Rossellomorea sp. could produce consistent extracellular phytate-degrading activity. The PCR amplification of β-propeller genes both in environmental samples and in the isolates obtained showed that this is the most ecologically relevant phytase type in the aquaponics systems used. In summary, the aquaponics system is abundant with bacteria carrying enzymes responsible for plant-nutrient mineralisation

Enzymes used in animal feed:leading technologies and forthcoming developments

Feed is the foremost and highest expense in large-scale breeding of monogastric animals, accounting for more than 70% of the total production costs. For more than 30 years, various enzymes have been used to improve the efficiency of feedstuff utilization. These enzymes are applied to simultaneously address many different practical problems in feed use, such as reducing the presence of antinutritional factors, increasing the digestibility of feed constituents, reducing the viscosity in the digestive tract, allowing the use of low-cost ingredients, and reducing environmental risks related to manure and waste disposal. The main feed enzymes in the market are phytases, xylanases and β-glucanases (cellulases). Nevertheless, other enzymes, such as mannanases, α-galactosidases, pectinases, amylases and proteases, are increasing in use. Poultry and swine sectors are the main feed enzyme consumers; however, ruminants, aquaculture and pets are projected to be large markets in the near future. Recent and future advancements in this field of knowledge are discussed here

Production of partially phosphorylated myo-inositol phosphates using phytases immobilised on magnetic nanoparticles

Phytases of different origin were covalently bound onto Fe3O4 magnetic nanoparticles (12 nm). Binding efficiencies of all three phytases were well above 70% relative to the number of aldehyde groups available on the surface of the magnetic nanoparticles. Temperature stability for all three phytases was enhanced as a consequence of immobilisation, whereas pH dependence of enzyme activity was not affected. Maximum catalytic activity of the immobilised phytases was found at 60°C (rye), 65°C (Aspergillus niger) and 70°C (Escherichia albertii). The immobilised enzymes exhibited the same excellent substrate specificities and unique myo-inositol phosphate phosphatase activities as their soluble counterparts. However, the catalytic turnover number dropped drastically for the immobilised phytases. The amount of the desired partially phosphorylated myo-inositol phosphate isomer could be easily controlled by the contact time of substrate solution and immobilised enzymes. The immobilised phytases showed a high operational stability by retaining almost full activity even after fifty uses

Phosphorus and Nitrogen Fertilization Effect on Phosphorus Uptake and Phosphatase Activity in Ryegrass and Tall Fescue Grown in a Chilean Andisol

A series of short-term experiments were carried out to assess the effect of phosphorus (P) and nitrogen (ammonium [NH(4) (+)-N] or nitrate [NO(3)(-)-N]) fertilization on P uptake and phosphatase activity in ryegrass and tall fescue cultivated under greenhouse conditions. Ryegrass or tall fescue plants were grown in an acidic Andisol in the presence or absence of P and increasing doses of NO(3)(-)-N or NH(4)(+)-N fertilizers. At the end of the experiment, soil phosphatase activity (P-ase(Rhiz)), pH, and Olsen-P were determined in the rhizosphere soil. Plant biomass, P uptake, and root surface phosphatase (P-ase(Root)) were also assayed for both plant species. Furthermore, soil incubation experiments at increasing doses of P, NO(3)(-)-N, or NH(4)(+)-N were performed to evaluate the fertilizer effect on soil phosphatase activity (P-ase(Bulk)) and microbial biomass carbon in the bulk soil. In the absence of plants, P-ase(Bulk) was inhibited and microbial biomass carbon was raised at increasing P supply levels. In the greenhouse experiments, P uptake by tall fescue was about 67% higher than that of ryegrass at low soil P availability, which suggests that tall fescue was less sensitive to P deficiency than ryegrass. For both plant species, P-ase(Rhiz) did not vary as a consequence of P addition. On the other hand, fertilization with the highest NH(4)(+)-N dose strongly decreased soil pH and shoot P content, as well as it increased P-ase(Root) activity. This fact denotes that P-ase(Root) behaved as a strategic response parameter to P stress with insufficient impact on plant P nutrition in both plant species

Performance of Seven Commercial Phytases in an in Vitro Simulation of Poultry Digestive Tract

The aim of,this study was to compare the biochemical, properties of seven commercially, available phytase products as well as their catalytic performance in an in vitro simulation of the digestive tract of poultry. Their enzymatic properties relevant with respect to phytate dephosphorylation in the digestive tract of birds were determined under identical assay conditions. All phytase-products included in the study showed an acid pH optimum of activity and were capable of releasing the organically bound phosphate from phytate during the in vitro simulation. However, their overall biochemical properties and relative catalytic performances were remarkably different The in vitro degradation system was considered as a simple and useful tool to evaluate the suitability of a phytase to be used as a feed supplement. Although relevant factors such as dietary P levels, intestinal phytase, and P absorption ate not implemented in the system, this approach might help to reduce the number of feeding trials necessary in the, search for a better Suited phytase for animal feeding application

A novel phosphorus biofertilization strategy using cattle manure treated with phytase-nanoclay complexes

The aim of this work was to evaluate the treatment of cattle manure with phytases stabilized in allophanic nanoclays as a potential novel phosphorus (P) biofertilization technology for crops grown in volcanic soils (Andisol). Furthermore, because the optimal pH for commercial phytase catalysis does not match the natural pH of manure, a complementary experiment was set up to evaluate the effect of manure inoculation with an alkaline phytase-producing bacterium. Finally, phytase-treated soil, manure, and soil-manure mixtures were evaluated for their P-supplying capacity to wheat plants grown under greenhouse conditions. Treating cattle manure with phytases stabilized in nanoclays resulted in a significant (P a parts per thousand currency signaEuro parts per thousand 0.05) increase of inorganic P in soil extracts (NaOH-EDTA and Olsen). The use of phytase-treated cattle manure increased dry weights by 10 % and the P concentration by 39 % in wheat plants grown under greenhouse conditions, which is equivalent to a P fertilizer rate of about 150 kg of P per hectare. The inoculation of cattle manure with beta-propeller phytase-producing bacteria led to an similar to 10 % increase in inorganic P in the manure extracts. However, applying inoculated manure to soil did not significantly increase wheat yield or P acquisition responses. Our results suggest that the novel approach of incubating cattle manure with phytases stabilized in nanoclay enhances the organic P cycling and P nutrition of plants grown in P-deficient soils