Unraveling the potential of bacterial phytases for sustainable management of phosphorous

Phosphorous actively participates in numerous metabolic and regulatory activities of almost all living organisms including animals and humans. Therefore, it is considered as an essential macronutrient required supporting their proper growth. On contrary, phytic acid (PA), an antinutritional substance, is widely known for its strong affinity to chelate essential mineral ions including PO4 3- , Ca2+ , Fe2+ , Mg2+ , and Zn2+ . Being one the major reservoir of PO4 3- ions, PA has great potential to bind PO4 3- ions in diverse range of foods. Once combined with P, PA transforms into an undigested and insoluble complex namely phytate. Produced phytate leads to a notable reduction in the bioavailability of P due to negligible activity of phytases in monogastric animals and humans. This highlights the importance and consequent need of enhancement of phytase level in these life forms. Interestingly, phytases, catalyzing the breakdown of phytate complex and recycling the phosphate into ecosystem to its available form, have naturally been reported in a variety of plants and microorganisms over past few decades. In pursuit of a reliable solution, the focus of this review is to explore the keynote potential of bacterial phytases for sustainable management of phosphorous via efficient utilization of soil phytate. The core of the review covers detailed discussion on bacterial phytases along with their widely reported applications viz. biofertilizers, phosphorus acquisition, and plant growth promotion. Moreover, meticulous description on fermentation-based strategies and future trends on bacterial phytases have also been included.

Effects of foliar fungicide on yield, micronutrients, and cadmium in grains from historical and modern hard winter wheat genotypes

Plant breeding and disease management practices have increased the grain yield of hard winter wheat (Triticum aestivum L.) adapted to the Great Plains of the United States during the last century. However, the effect of genetic gains for seed yield and the application of fungicide on the micronutrient and cadmium (Cd) concentration in wheat grains is still unclear. The objectives of this study were to evaluate the effects of fungicide application on the productivity and nutritional quality of wheat cultivars representing 80 years of plant breeding efforts. Field experiments were conducted over two crop years (2017 and 2018) with eighteen hard winter wheat genotypes released between 1933 and 2013 in the presence or absence of fungicide application. For each growing season, the treatments were arranged in a split-plot design with the fungicide levels (treated and untreated) as the whole plot treatments and the genotypes as split-plot treatments in triplicate. The effects on seed yield, grain protein concentration (GPC), micronutrients, phytic acid, and Cd in grains were measured. While the yield of wheat was found to increase at annualized rates of 26.5 and 13.0 kg ha-1 yr-1 in the presence and absence of fungicide (P < 0.001), respectively, GPC (-190 and -180 mg kg-1 yr-1, P < 0.001), Fe (-35.0 and -44.0 μg kg-1 yr-1, P < 0.05), and Zn (-68.0 and -57.0 μg kg-1 yr-1, P < 0.01) significantly decreased during the period studied. In contrast to the other mineral elements, grain Cd significantly increased over time (0.4 μg kg-1 yr-1, P < 0.01) in the absence of fungicide. The results from this study are of great concern, as many mineral elements essential for human nutrition have decreased over time while the toxic heavy metal, Cd, has increased, indicating modern wheats are becoming a better vector of dietary Cd.

INVESTIGATION OF CHANGING PHYTIC ACID IN LEGUMINOUS SEEDS DEPENDING ON SOAKING AND SPROUTING CONDITIONS

The results of studying changes of phytic acid in seeds of soya of “Diamond” variety and ones of chick-pea of “Krasnokutsky – 195” depending on seed soaking and sprouting conditions are presented. The content of phytic acid and changes of phytic globoloids in native soya and chick-pea seeds, sprouted in water, sprouted in the solution of mineral salts, preliminarily washed by the solution of lemon acid (C6Н8О7) were studied. The research topicality is conditioned by the necessity to develop food technologies using vegetable protein, which agent is soya and chick-pea, and to develop technological methods, favoring phytic acid inactivation. As a result of the study, it has been established, that a decrease of the phytic acid content in soya and chick-pea seeds is influenced by the sprouting process, and seeds washing by C6Н8О7 solution (pH – 3.5) is a catalyst of these processes.   Soya seeds, sprouted in the potassium iodide solution (PI), and chick-pea seeds, sprouted in the sodium hydroselenite (NaHSeO3), preliminarily washed by C6Н8О7 solution (pH – 3.5), have less content of phytic acid, comparing with other samples.    The phytic acid content decrease has been proved by a phytic globoloid decrease. It has been established, that the least diameter of a phytic globoloid is inherent to samples of soya, sprouted in PI solution and washed by C6Н8О7 solution (pH – 3.5), – 3.2 mcm, and a sample of chick-pea seeds, sprouted in NaHSeO3 solution, washed by C6Н8О7 solution (pH – 3.5) – 3.0 mcm. An undesirable “pea” smell also disappears. The established regularities are important for scientists because they allow to widen the assortment of products with vegetable protein, safe for the human organism

Globoids and Phytase: The Mineral Storage and Release System in Seeds

Phytate and phytases in seeds are the subjects of numerous studies, dating back as far as the early 20th century. Most of these studies concern the anti-nutritional properties of phytate, and the prospect of alleviating the effects of phytate with phytase. As reasonable as this may be, it has led to a fragmentation of knowledge, which hampers the appreciation of the physiological system at hand. In this review, we integrate the existing knowledge on the chemistry and biosynthesis of phytate, the globoid cellular structure, and recent advances on plant phytases. We highlight that these components make up a system that serves to store and-in due time-release the seed's reserves of the mineral nutrients phosphorous, potassium, magnesium, and others, as well as inositol and protein. The central component of the system, the phytate anion, is inherently rich in phosphorous and inositol. The chemical properties of phytate enable it to sequester additional cationic nutrients. Compartmentalization and membrane transport processes regulate the buildup of phytate and its associated nutrients, resulting in globoid storage structures. We suggest, based on the current evidence, that the degradation of the globoid and the mobilization of the nutrients also depend on membrane transport processes, as well as the enzymatic action of phytase.

Instability of endosperm development in amphiploids and their parental species in the genus Avena L

The development of oat endosperm is modified by chromatin and nuclei elimination, intrusive growth of cell walls, and polyploidisation of cell clones. The last event is correlated with somatic crossing-over. Grass endosperm is a variable tissue in terms of its cytogenetics and development. Free-nuclear syncytium and starchy and aleurone endosperm were the main focus of the research. These were studied in oat amphiploids (4x, 6x, and 8x) and parental species (2x, 4x, and 6x). What the levels of cytogenetic disorders and developmental anomalies in species versus hybrids are, and, what the factors are determining phenotypes of both tissue components, are open questions for oats. Chromosome bridges and micronuclei are the main cytogenetic disorders showing the elimination of parts of genomes. Bridges are formed by the AT-heterochromatin-rich and -free ends of chromosomes. In the starchy tissue, various sectors are separated structurally due to the elongation or intrusive growth of aleurone cells. The development of the aleurone layer is highly disturbed locally due to the amplification of aleurone cell divisions. Changes related to their structure and metabolism occur in the aleurone cells, for example, clones of small versus large aleurone cells. Somatic crossing-over (SCO) is expressed in clones of large polyploidised cells (r = 0.80***), giving rise to new aleurone phenotypes. The multivariate description of the endosperm instability showed that endospermal disorders were more frequent in amphiploids than in the oat species. Avena strigosa and the amphiploid A. fatua × A. sterilis appeared to be extreme units in an ordination space. Nuclear DNA elimination, periclinal and multidirectional cytokineses, polyploidisation, intrusive growth, and SCO appeared to be important factors determining oat endospermal variations.

Analytical-performance improvement of laser-induced breakdown spectroscopy for the processing degree of wheat flour using a continuous wavelet transform

Quality and safety of food are two of the most important matters in our lives. Wheat is one of the most important products in the modern agricultural processing industry. Issues of mislabeling and adulteration are of increasingly serious concern in the grain market. They threaten the credibility of producers and traders and the rights of the consumers. Therefore, it is very significant to guarantee the processing degree of wheat flour. In this work, two different spectral peak recognition methods, i.e., artificial spectral peak recognition and automatic spectral peak recognition, are carried out to study the adulteration problem in the food industry. Three grades of the processing degree of wheat flour from northern China are classified by laser-induced breakdown spectroscopy (LIBS). To search for an automatic classification model, continuous wavelet transform is used for the automatic recognition of the LIBS spectrum peak. Principal component analysis is used to reduce the collinearity of LIBS spectra data. First, 20 principal components were selected to represent the spectral data for the following discrimination analysis by a support vector machine. The results showed that the classification accuracies of automatic spectral peak recognition are better than those of artificial spectral peak recognition. The classification accuracies of artificial spectral peak recognition and automatic spectral peak recognition are 95.33% and 98.67%; the fivefold cross-validation classification accuracies are 94.67% and 96.67%; and the operation times were 240 min and 2 min, respectively. It can be concluded that LIBS can provide simpler and faster classification without the use of any chemical reagent, which represents a decisive advantage for applications dedicated to rapidly detecting the processing degree of wheat flour and other cereals.

Performance, intestinal microflora, and amino acid digestibility altered by exogenous enzymes in broilers fed wheat- or sorghum-based diets

The objective of the current study was to compare the effects of dietary enzymes and nutrient restriction on performance and bone mineralization in birds fed wheat- or sorghum-based diets. A total of 720 d-old male broiler chicks were randomly allocated to 8 treatments, with 6 replicates per treatment and 15 birds per replicate. Birds were reared in floor pens from 0 to 35 d. The study used a 2 × 4 factorial arrangement with 2 grains (sorghum or wheat) and 4 diets: positive control (no enzyme and ME, digestible Lys, Ca, and P sufficient, negative control (NC; no enzyme and reduced ME [-100 kcal/kg], digestible AA [-2%], Ca [-0.12 percentage points], and available P [-0.18 percentage points in the starter phase and -0.22 percentage points in the grower phase]), NC + nonstarch polysaccharide-degrading enzymes + phytase (500 phytase units [FTU]; NCCP), and NC + phytase (1,000 FTU; NCP). From 0 to 35 d, birds fed wheat-based diets had greater G:F (4.5%), BW gain (9.2%), breast meat yield (6.8%), and tibia ash (2.0%) compared with birds fed sorghum-based diets. Across grain types, the NCCP treatment improved BW gain ( < 0.001), feed intake ( < 0.001), G:F ( < 0.05), and livability ( < 0.001) compared with the NC treatment. Birds fed NCP had greater BW gain ( < 0.001), feed intake ( < 0.001), G:F ( < 0.001), and livability ( < 0.001) compared with birds fed NC. Birds fed the NCP diet had greater BW gain ( < 0.001), toe ash ( < 0.01), and tibia ash ( < 0.001) compared with birds fed the NCCP diet. There was a grain × diet interaction for feed intake ( < 0.01), BW gain ( < 0.001), tibia ash ( < 0.01), and tibia breaking strength ( < 0.05). The influence of enzymes was more pronounced in sorghum-based diets than in wheat-based diets. Birds fed wheat-based diets had greater ileal digestibility of His, Met, Val, Phe, Ile, Leu, Trp, Glu, Pro, Ala, Tyr, and Cys compared with those fed sorghum-based diets ( < 0.05). Across grain types, NCP had greater apparent ileal digestibility of Met, Lys, Ser, Pro, Gly, and Cys than NC ( < 0.05). The results suggest that wheat is superior to sorghum for broilers, as expected, but that enzyme supplementation has the capability to restore the compromised bird performance due to feeding sorghum. In addition, compared with nonstarch polysaccharide-degrading enzymes and phytase (500 FTU/kg feed) added in concert, phytase supplemented at 1,000 FTU/kg resulted in a further improvement of some of the performance and bone mineralization parameters in male broilers fed sorghum-based diets.

Spatial X-ray fluorescence micro-imaging of minerals in grain tissues of wheat and related genotypes

Wheat and its related genotypes show distinct distribution patterns for mineral nutrients in maternal and filial tissues in grains. X-ray-based imaging techniques are very informative to identify genotypes with contrasting tissue-specific localization of different elements. This can help in the selection of suitable genotypes for nutritional improvement of food grain crops. Understanding mineral localization in cereal grains is important for their nutritional improvement. Spatial distribution of mineral nutrients (Mg, P, S, K, Ca, Fe, Zn, Mn and Cu) was investigated between and within the maternal and filial tissues in grains of two wheat cultivars (Triticum aestivum Cv. WH291 and WL711), a landrace (T. aestivum L. IITR26) and a related wild species Aegilops kotschyi, using micro-proton-induced X-ray emission (µ-PIXE) and micro-X-ray fluorescence (µ-XRF). Aleurone and scutellum were major storage tissues for macro (P, K, Ca and Mg) as well as micro (Fe, Zn, Cu and Mn) nutrients. Distinct elemental distribution patterns were observed in each of the four genotypes. A. kotschyi, the wild relative of wheat and the landrace, T. aestivum L. IITR26, accumulated more Zn and Fe in scutellum and aleurone than the cultivated wheat varieties, WH291 and WL711. The landrace IITR26, accumulated far more S in grains, Mn in scutellum, aleurone and embryo region, Ca and Cu in aleurone and scutellum, and Mg, K and P in scutellum than the other genotypes. Unlike wheat, lower Mn and higher Fe, Cu and Zn concentrations were noticed in the pigment strand of A. kotschyi. Multivariate statistical analysis, performed on mineral distribution in major grain tissues (aleurone, scutellum, endosperm and embryo region) resolved the four genotypes into distinct clusters.

Relevance for food sciences of quantitative spatially resolved element profile investigations in wheat (Triticum aestivum) grain

Bulk element concentrations of whole grain and element spatial distributions at the tissue level were investigated in wheat (Triticum aestivum) grain grown in Zn-enriched soil. Inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry were used for bulk analysis, whereas micro-proton-induced X-ray emission was used to resolve the two-dimensional localization of the elements. Soil Zn application did not significantly affect the grain yield, but did significantly increase the grain Ca, Fe and Zn concentrations, and decrease the grain Na, P and Mo concentrations; bulk Mg, S, K, Mn, Cu, Cd and Pb concentrations remained unchanged. These changes observed in bulk element concentrations are the reflection of tissue-specific variations within the grain, revealing that Zn application to soil can lead to considerable alterations in the element distributions within the grain, which might ultimately influence the quality of the milling fractions. Spatially resolved investigations into the partitioning of the element concentrations identified the tissues with the highest element concentrations, which is of utmost importance for accurate prediction of element losses during the grain milling and polishing processes.

New insights into globoids of protein storage vacuoles in wheat aleurone using synchrotron soft X-ray microscopy

Mature developed seeds are physiologically and biochemically committed to store nutrients, principally as starch, protein, oils, and minerals. The composition and distribution of elements inside the aleurone cell layer reflect their biogenesis, structural characteristics, and physiological functions. It is therefore of primary importance to understand the mechanisms underlying metal ion accumulation, distribution, storage, and bioavailability in aleurone subcellular organelles for seed fortification purposes. Synchrotron radiation soft X-ray full-field imaging mode (FFIM) and low-energy X-ray fluorescence (LEXRF) spectromicroscopy were applied to characterize major structural features and the subcellular distribution of physiologically important elements (Zn, Fe, Na, Mg, Al, Si, and P). These direct imaging methods reveal the accumulation patterns between the apoplast and symplast, and highlight the importance of globoids with phytic acid mineral salts and walls as preferential storage structures. C, N, and O chemical topographies are directly linked to the structural backbone of plant substructures. Zn, Fe, Na, Mg, Al, and P were linked to globoid structures within protein storage vacuoles with variable levels of co-localization. Si distribution was atypical, being contained in the aleurone apoplast and symplast, supporting a physiological role for Si in addition to its structural function. These results reveal that the immobilization of metals within the observed endomembrane structures presents a structural and functional barrier and affects bioavailability. The combination of high spatial and chemical X-ray microscopy techniques highlights how in situ analysis can yield new insights into the complexity of the wheat aleurone layer, whose precise biochemical composition, morphology, and structural characteristics are still not unequivocally resolved.

Review: Supplementation of phytase and carbohydrases to diets for poultry

Woyengo, T. A. and Nyachoti, C. M. 2011. Review: Supplementation of phytase and carbohydrases to diets for poultry. Can. J. Anim. Sci. 91: 177–192. Feedstuffs of plant origin contain anti-nutritional factors such as phytic acid (PA) and non-starch polysaccharides (NSP), which limit nutrient utilization in poultry. Phytic acid contains phosphorus, which is poorly digested by poultry, and has the capacity to bind to and reduce the utilisation of other nutrients, whereas NSP are indigestible and have the capacity to reduce nutrient utilisation by encapsulation. Supplemental phytase and NSP-degrading enzymes (carbohydrases) can, respectively, hydrolyze PA and NSP, alleviating the negative effects of these anti-nutritional factors. In feedstuffs of plant origin, PA is located within the cells, whereas NSP are located in cell walls, and hence it has been hypothesized that phytase and carbohydrases can act synergistically in improving nutrient utilization because the carbohydrases can hydrolyze the NSP in cell walls to increase the accessibility of phytase to PA. However, the response to supplementation of a combination of these enzymes is variable and dependent on several factors, including the type of carbohydrase supplement used, dietary NSP composition, calcium and non-phytate phosphorus contents, and endogenous phytase activity. These factors are discussed, and areas that need further research for optimising the use of a combination of phytase and carbohydrases in poultry diets are suggested.

Ileal digestibility and endogenous flow of minerals and amino acids: responses to dietary phytic acid in piglets

Effects of phytic acid (PA) on ileal mineral and amino acid (AA) digestibilities and ileal endogenous AA flow in piglets were investigated. Seven ileal-cannulated weanling pigs were fed a casein–maize starch-based diet with PA (as sodium phytate) at 0, 5, 10 or 20 g/kg in 4 × 4 Latin square design with three added columns to give seven observations per treatment. The basal diet was formulated to meet National Research Council energy and AA requirements for piglets. The respective digestibility and endogenous lysine loss were determined by indicator and homoarginine methods. The apparent ileal digestibility (AID) of Na, K and P was linearly and quadratically reduced (P < 0·05) by increased dietary PA concentration, whereas that of Ca and Mg was only linearly reduced (P < 0·05) by the dietary PA. The AID values for Mg and Na were negative ( − 0·03 and − 0·18, respectively) when PA was supplemented at 20 g/kg. The AID of isoleucine, leucine and valine responded quadratically to dietary PA concentration, though the differences between the AID values of the AA due to change in dietary PA concentration were marginal (at most by 1·8 percentage units). Furthermore, dietary PA did not affect (P>0·05) endogenous AA losses. The results suggest that PA has limited effect on the digestibility and endogenous losses of AA in piglets, but can reduce AID of Mg and Na partly by increasing endogenous losses of these minerals as evidenced by their negative AID values.

Biofortification of crops with seven mineral elements often lacking in human diets--iron, zinc, copper, calcium, magnesium, selenium and iodine

The diets of over two-thirds of the world's population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification). This article reviews aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se). Two complementary approaches have been successfully adopted to increase the concentrations of bioavailable mineral elements in food crops. First, agronomic approaches optimizing the application of mineral fertilizers and/or improving the solubilization and mobilization of mineral elements in the soil have been implemented. Secondly, crops have been developed with: increased abilities to acquire mineral elements and accumulate them in edible tissues; increased concentrations of 'promoter' substances, such as ascorbate, beta-carotene and cysteine-rich polypeptides which stimulate the absorption of essential mineral elements by the gut; and reduced concentrations of 'antinutrients', such as oxalate, polyphenolics or phytate, which interfere with their absorption. These approaches are addressing mineral malnutrition in humans globally.

Quantitative analysis of phytate globoids isolated from wheat bran and characterization of their sequential dephosphorylation by wheat phytase

Wheat phytase was purified to investigate the action of the enzyme toward its pure substrate (phytic acid - myo-inositol hexakisphosphate) and its naturally occurring substrate (phytate globoids). Phytate globoids were purified to homogeneity from wheat bran, and their nutritionally relevant parameters were quantified by ICP-MS. The main components of the globoids were phytic acid (40% w/w), protein (46% w/w), and several minerals, in particular, K > Mg > Ca > Fe (in concentration order). Investigation of enzyme kinetics revealed that K(m) and V(max) decreased by 29 and 37%, respectively, when pure phytic acid was replaced with phytate globoids as substrate. Time course degradation of phytic acid or phytate globoids using purified wheat phytase was followed by HPIC identification of inositol phosphates appearing and disappearing as products. In both cases, enzymatic degradation initiated at both the 3- and 6-positions of phytic acid and end products were inositol and phosphate.

Comparison of the phosphorus and mineral concentrations in bran and abraded kernel fractions of a normal barley (Hordeum vulgare) cultivar versus four low phytic acid isolines

Phytic acid consists of 65-80% of the total phosphorus (P) in cereal grains. Its salts are concentrated in the germ and aleurone layers, which are typically removed during milling. We hypothesize that concentrations of different types of P and minerals in milled products will be greatly altered in low phytic acid (lpa) barleys. Seeds of cv. Harrington (control) and four lpa isolines-lpa1-1, lpa2-1, lpa3-1, and M955-were abraded by a laboratory method into five surface layer and four remaining kernel fractions. Results show that phytic acid in the four lpa lines ranged from 75% to 5% of the control. The decrease in phytic acid P concentration was matched almost equally by an increase in inorganic P, so that the rest of P (the sum of all P-containing compounds other than phytic acid P and inorganic P) and total P levels remained relatively unchanged among the five genotypes. These trends were also observed for the processed fractions. The major mineral elements in barley seeds were P, K, Mg, S, and Ca, while minor ones were Fe, Zn, Mn, Cu, and Ba. All types of P and other minerals measured were generally concentrated in the outer layers of the grain. Although there were substantial differences in mineral contents of bran fractions among genotypes, the level of phytic acid P had little effect on mineral contents in whole or abraded kernels. One major exception was Fe, which had the highest level in all tissues of M955 genotype. The above findings were all confirmed by analyzing another set of barley samples grown in a different environment. Thus, in general, breeding lpa barleys does not lead to reduced mineral contents in whole grains or elevated mineral levels in milled products.