Soluble Sources Research Articles

304 Investigating the Impact of Fiber Type and Multicarbohydrase Supplementation on Nutrient Digestibility and Energy Balance of Gestating Sows

Abstract Supplementing fiber-degrading enzymes in grow-finish pig diets has been shown to improve energy and nutrient digestibility. However, there is a paucity of research on their effectiveness in gestation diets. The experimental objective was to evaluate the efficacy of multicarbohydrase supplementation in the presence of soluble (20% sugar beet pulp) and insoluble (20% corn DDGS) dietary fiber sources on the apparent total tract digestibility (ATTD) of nutrients and energy balance of sows at mid- and late-gestation. A total of 36 confirmed gestating sows (186 ± 4.6 kg BW) were blocked by parity randomly assigned to 1 of 4 diets (n = 8) in a 2×2 factorial arrangement of treatments on day 28 of gestation. Factors included fiber type of insoluble (IF; 16.91 IDF%) or soluble fiber (SF; 5.26 SDF%) and with (+) or without (-) enzyme supplementation (0.05%, Rovabio Advance P10; Adisseo, Antony, France). Diets were fed from day 28 to 109 of gestation at a feeding level of 2.1 kg (SID-Lys 11 g/d and 4.5 NE-Mcal/d). Diets contained 0.5% of TiO2. Two separate 9-d metabolism periods were conducted on days 50 to 59 (mid-) and 99 to 108 (late-) of gestation. During each period, days 1-3 served as an environmental adaptation period, days 4-7 total urine and feces were collected (96-h) and followed by a 48-h lactulose-mannitol study. Data were analyzed as repeated records using a linear mixed model with block as a random effect, and fiber type, enzyme, and period and their interactions as fixed effects. Multicarbohydrase supplementation increased the ATTD of GE, DM, and NDF by 2.8%, 3.4%, and 8.3%, respectively (Enzyme P < 0.05). There was a tendency for a Period × Fiber × Enzyme interaction for the ATTD of ADF, whereas multicarbohydrase supplementation with SF increased ADF digestibility in mid-gestation by 6.5%, but not in late gestation (P = 0.051). Compared with IF-, the ATTD of hemicellulose was 5.3% greater in sows fed IF+ but did not differ from SF- and SF+ (Fiber×Enzyme P=0.037). Furthermore, in late gestation sows fed IF had 11% greater ATTD of hemicellulose (Period×Fiber P = 0.035). Energy intake did not differ as dictated by design (P = 0.64). Sows fed multicarbohydrases excreted less energy in their urine (519 vs. 469 GE kcal/d; Enzyme P = 0.033) and in their feces (985 vs. 900 GE kcal/d; Enzyme P = 0.003). This resulted in an improvement in both DE (3,723 vs. 3,856 kcal/kg; Enzyme P < 0.01) and ME (3,484 vs. 3,583 kcal/kg; Enzyme P = 0.041), irrespective of fiber type. In late-gestation, sows fed SF tended to have decreased GE excretion compared with IF (Period×Fiber P = 0.091). Sows had a 3.5% greater ME in late-gestation (3,451 vs. 3,572 kcal/kg; Period P < 0.01). In conclusion, multicarbohydrase supplementation increased the energetic contribution of IF and SF in sow diets, and sows have increased fiber and energy digestibility in late gestation.

Methanogens acquire and bioaccumulate nickel during reductive dissolution of nickelian pyrite.

Nickel (Ni) is a key component of the active site metallocofactors of numerous enzymes required for methanogenesis, including [NiFe]-hydrogenase, carbon monoxide dehydrogenase, and methyl CoM reductase, leading to a high demand for Ni among methanogens. However, methanogens often inhabit euxinic environments that favor the sequestration of nickel as metal-sulfide minerals, such as nickelian pyrite [(Ni,Fe)S2], that have low solubilities and that are not considered bioavailable. Recently, however, several different model methanogens (Methanosarcina barkeri, Methanococcus voltae, Methanococcus maripaludis) were shown to reductively dissolve pyrite (FeS2) and to utilize dissolution products to meet iron and sulfur biosynthetic demands. Here, using M. barkeri Fusaro, and laboratory-synthesized (Ni,Fe)S2 that was physically isolated from cells using dialysis membranes, we show that trace nickel (<20 nM) abiotically solubilized from the mineral can support methanogenesis and limited growth, roughly fivefold less than the minimum concentration known to support methanogenesis. Furthermore, when provided direct contact with (Ni,Fe)S2, M. barkeri promoted the reductive dissolution of (Ni,Fe)S2 and assimilated solubilized nickel, iron, and sulfur as its sole source of these elements. Cells that reductively dissolved (Ni,Fe)S2 bioaccumulated approximately fourfold more nickel than those grown with soluble nickel and sulfide but had similar metabolic coupling efficiencies. While the mechanism for Ni uptake in archaeal methanogens is not known, homologs of the bacterial Nik uptake system were shown to be ubiquitous across methanogen genomes. Collectively, these observations indicate that (Ni,Fe)S2 is bioavailable in anoxic environments and that methanogens can convert this mineral into nickel-, iron-, and sulfur-containing metalloenzymes to support methanogenesis and growth. IMPORTANCE Nickel is an essential metal, and its availability has changed dramatically over Earth history due to shifts in the predominant type of volcanism in the late Archean that limited its availability and an increase in euxinic conditions in the early Proterozoic that favored its precipitation as nickel sulfide minerals. Observations presented herein indicate that the methanogen, Methanosarcina barkeri, can acquire nickel at low concentration (<20 nM) from soluble and mineral sources. Furthermore, M. barkeri was shown to actively reduce nickelian pyrite; use dissolution products to meet their iron, sulfur, and nickel demands; and bioaccumulate nickel. These data help to explain how M. barkeri (and possibly other methanogens and anaerobes) can acquire nickel in contemporary and past anoxic or euxinic environments.

Beet pulp as soluble fiber source and dietary energy levels for growing pigs under heat stress.

The study evaluated the effects of dietary fiber and energy levels administered during two growing periods (d 0-28 and d 29-56) for pigs exposed to a high temperature. A total of 96 growing pigs were used in six treatments as: Two treatments in thermoneutral temperature (21°C-24°C) with dietary energy of 3,300 and the inclusion of high or low fiber, two treatments in heat stress (30°C-34°C) with dietary energy of 3,300 and the inclusion of high or low fiber, and two treatments in heat stress with dietary energy of 3,450 and the inclusion of high or low fiber. Among standard energy level treatments, heat-stressed pigs showed lower average daily gain (ADG), feed intake, digestibility of dry matter, gross energy, crude protein, and crude fiber in phases 1 and 2. Moreover, higher concentrations of acetate, propionate, butyrate, and total short-chain fatty acid (SCFA) in feces were shown in pigs fed high fiber diets. There was a negative interaction between dietary fiber and energy for the fecal concentration of isobutyrate in phase 1 and valerate in phase 2. Pigs in heat stress treatments showed a higher rectal temperature, respiratory rate, hair cortisol, plasma zonulin, and fecal lipocalin-2. Among heat stress treatments, the overall ADG was increased in pigs fed high fiber. Pigs fed high dietary fiber showed a greater concentration of acetate, propionate, butyrate, and total SCFA. High fiber treatments decreased plasma zonulin. In conclusion, the inclusion of beet pulp, soluble fiber, at the level of 4% looks necessary in pigs diet during heat stress.

Simple and Complex Substrates (Sugar, Acetate and Milk Whey) for In Situ Bioremediation of Groundwater with Nitrate and Actinide Contamination

The complex contamination of groundwater near radioactive waste repositories by nitrates and actinides is a common problem for many nuclear fuel cycle facilities. One of the effective methods to remove nitrates and reduce actinide migration activity is bioremediation through the activation of native microbial communities by soluble electron donors and carbon sources. This work evaluated the effectiveness of using simple and complex electron donors to remove nitrate in the microbial community in an aquifer near the B2 storage of the Siberian Chemical Combine (Seversk, Siberia). The addition of sugar and milk whey led to the maximum efficiency of nitrate-ion removal and a decrease in the redox potential of the system, creating optimal conditions for the immobilization of actinide. Special attention was paid to the behavior of uranium, plutonium, neptunium, and americium under conditions simulating groundwater when sugar, acetate, and milk whey were added and when microbial metabolic products were formed. Neither microbial metabolites nor organic solutions were found to have a significant effect on the leaching of neptunium. At the same time, for plutonium, a decrease in yield was observed when rocks were treated with organic solutions were compared to groundwater treatment without them. Plutonium leaching is significantly affected by rock composition. In rocks with a low clay fraction content, its yield can reach 40%. At the same time, microbial metabolites can increase americium (Am) desorption from rocks with a low clay fraction content. Additionally, particle size analysis was performed using a step-by-step filtration approach, aiming to evaluate the risks that are associated with colloidal phase formation. It was shown that microbiological stimulation resulted in particle enlargement, substantially diminishing the presence of actinides in the form of dissolved or sub-50 nm nanoparticles. This outcome significantly reduced the potential for colloidal and pseudocolloidal transfer, thereby lowering associated risks.

Effect of Almond (Prunus dulcis) Hull Addition to Alfalfa Silage on Silage Quality and In Vitro Digestibility

In this study, it was aimed to determine the effects of the addition of almond hull, which has no economic value and causes environmental pollution, to alfalfa silage as an easily soluble carbohydrate source on silage quality, fermentation characteristics and in vitro organic matter digestion (IVOMD). The groups were designed to contain 0% (control), 1%, 2%, 4% and 6% almond hull, respectively. When the IVOMD and metabolizable energy (ME) values of the silages were examined, increases were observed in all additive groups compared to the control group. When the pH, NH3-N/TN and carbon dioxide (CO2) values of the silages were examined, the highest values were determined in the control group, while the lowest pH, NH3-N/TN and CO2 values were determined in the silage group with 6% almond hull added. Although an increase was determined in all trial groups in terms of lactic acid (LA) and acetic acid (AA) values of silages compared to the control group, the highest values were determined in the group with 6% almond hull addition, and a decrease was determined due to the increase in almond hull in terms of butyric acid (BA) values. Yeast and mold values of the silages decreased due to the increase in almond hull compared to the control group. As a re- sult, it was determined that the addition of 6% almond hull as an easily soluble carbohydrate source had a positive effect on alfalfa silage quality and fermentation characteristics.

Phosphate solubilizing rhizobacteria inoculation to increase rock phosphates efficiency and improve maize growth

Rock phosphates are less soluble and agronomically not as efficient as the acidulated. However, some rhizobacteria can improve the solubilization of inorganic phosphates in the soil, raising the efficiency of the rock phosphates. The objective was to evaluate the development of maize plants in response to the application of soluble and rock P sources associated with rhizobacteria inoculation. A greenhouse experiment was carried out with six P sources: no P application; ​​Triple Superphosphate (TSPh); Gafsa rock phosphate (reactive); Itafós rock phosphate (non-reactive); TSPh + Gafsa; and TSPh + Itafós, and three inoculation forms: no inoculation, Burkholderia pickettii GN 2214 and Pseudomonas sp. fluorescens group P21. Plant height, stem diameter, leaf area, shoot dry weight (ShDW), root dry weight (RDW), total dry weight, cumulative P content in ShDW, RDW/ShDW ratio and relative agronomic efficiency were assessed. Agronomic efficiency and growth of the TSPh-treated plants were better than of those treated with rock phosphates. The association of TSPh with rock phosphates increases the agronomic efficiency and maize plant growth more than the isolated rock sources. Inoculation with P. fluorescens strain P21, improved the performance of maize fertilized with Gafsa phosphate, but had no effect when associated with Itafós phosphate. Together with TSPh, inoculation intensified shoot and root growth, indicating the potential to increase the efficiency of soluble sources as well.

Trace metal dissolution kinetics of East Asian size-fractionated aerosols in seawater: The effect of a model siderophore

Aerosol soluble metals are considered bioavailable to marine phytoplankton and may influence phytoplankton growth, their community structure, and material cycling in the ocean. The dissolution is controlled by the physical and chemical properties of aerosols and various atmospheric, physical, and biogeochemical processes before and after depositing in the surface water. Among these complicated processes, the interaction of aerosol metals with organic ligands in seawater is one of the major factors. In this study, we systematically investigated the dissolution kinetics of trace metals from fine (0.45–0.95 μm) and coarse (>7.2 μm) aerosols in seawater for 30 days under conditions with or without adding a model Fe organic ligand, siderophore desferrioxamine B (DFB). We found that most of the soluble metals in the fine aerosols were leached rapidly within the first hour. In terms of the coarse aerosols, with DFB addition, the fractional solubility of Fe increased substantially from 0.1 to 10%, and the solubilities of most other metals generally increased by about 2-fold within 30 days. Without DFB addition, we found that most soluble metals were still gradually released over time in coarse aerosols, except particle-reactive metals, Fe and Pb. We further observed strong linear correlations between dissolved metals (Al, Fe, Mn, Co, Ni, and Zn) and silicate concentrations for DFB addition with coarse aerosols, with metal to silicate ratios comparable to those of typical aluminosilicates. Quantitatively, the aluminosilicate-associated dissolved metals accounted for >85% of total dissolved Fe, Al, and Co, and 40–60% for total dissolved Mn and Ni with the addition of DFB for 30 days. By comparing dissolved metal to Al ratios with lithogenic ratios, the metals leached in the first hour for both coarse and fine aerosols originated from anthropogenic sources, and lithogenic aerosols gradually became the dominant soluble metal source for coarse aerosols after 1 h, extending to 720 h. The findings of this study exhibit the importance of the time-dependent interaction of lithogenic aerosols with organic ligands in seawater. The residence time of aerosol particles and the concentrations of available organic ligands in the euphotic zone are key factors affecting aerosol dissolved metal availability to marine phytoplankton in the surface ocean.

Yonca Silajına Pasta Atığı İlavesinin Silaj Kalitesi ve Fermantasyon Özellikleri Üzerine Etkisi

In this study, it was aimed to determine the effects of addition of cake waste, which is a food industry waste, to alfalfa silage as a readily soluble carbohydrate source on silage quality, fermentation properties, in vitro organic matter digestion and in vitro CH4 values. In the study, while silage group without additives constituted the control group, silages with 1%, 2%, 4% and 6% cake waste additions constituted the test groups. Statistically significant differences were found in crude protein (CP), crude ash (CA), dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), in vitro organic matter digestion (IVOMD), metabolizable energy (ME) and in vitro CH4 values of silages (P

Evaluation of the Usage of Wafer Waste as an Easily Soluble Carbohydrate Source in Alfalfa Silage

This study examined the addition of wafer waste as a readily soluble carbohydrate source to alfalfa silage for its impact on silage quality, fermentation characteristics, in vitro organic matter digestion, and in vitro CH4 values. Fresh alfalfa was ensiled with 0% wafer waste (Control), 1% wafer waste, 2% wafer waste, 4% wafer waste, and 6% wafer waste for 60 days. The differences between the groups in dry matter (DM), crude protein (CP), crude ash (CA), neutral detergent fiber (NDF), acid detergent fiber (ADF), metabolizable energy (ME), in vitro organic matter digestion (IVOMD), and in vitro CH4 values of silages were found to be statistically significant. In comparison to the control group, increases in IVOMD and ME values were seen in all additive-containing groups. Depending on the quantity of wafer waste, the pH, ammonia nitrogen (NH3-N/TN), and carbon dioxide (CO2) values of the silages declined. In the study, the highest amount of lactic acid occurred in the group with 6% wafer waste added. Propionic acid (PA) was detected only in the control group. Butyric acid (BA) values tended to decrease depending on the addition of wafer waste and were not found in the groups to which 4% and 6% wafer waste addition. Yeast and mold values of the silages decreased in parallel with the increase in the wafer waste rate. As a result, it was determined that adding wafer waste as an easily soluble carbohydrate source positively affected alfalfa silage quality and fermentation characteristics.

Effect of adding lactic acid bacteria to maize silage on nutritive quality, fermentation properties and in vitro digestibility

This study aimed to determine the effects of adding lactic acid bacteria to maize silage on the nutritionalf quality, its fermentation properties and its in vitro organic matter digestion (IVOMD). In the study, pre-fermented juices (PFJ) prepared from different water-soluble carbohydrate (WSC) sources at the rate of 5% and commercial homofermentative and heterofermentative lactic acid bacteria (LAB) were added to silages. Groups were designed as (I) control, (II) Glucose-PFJ, (III) Fructose-PFJ, (IV) Sucrose-PFJ, (V) Molasses-PFJ, (VI) Homofermentative LAB (HoLAB) and (VII) Heterofermentative LAB (HetLAB). When the lactic acid bacteria (LAB) count, lactic acid (LA), acetic acid (AA), LA/AA ratio, pH and yeast values of the natural fermented lactic acid bacteria liquids prepared by adding 5% different easily soluble carbohydrate sources to meadow grass fermentation values of the groups were examined, the differences between them were statistically significant. &#x0D; The differences between the groups in the CA, ADF, IVOMD and methane (CH4) values of the silage groups prepared by adding PFJ were found to be statistically significant. The differences in the fermentation characteristics of the silages (pH, ammonia-nitrogen (NH3-N), LA, AA, LA/AA, CO2 and total yeast mold after aerobic stability) were statistically significant. When all parameters were examined, it was concluded that the addition of PFJ, which is prepared by adding 5% fructose to the meadow grass plant, to the maize silage has positive effects on IVOMD, ME, CH4, LA and yeast-mold and can be used instead of commercial inoculants.

Ophthalmic glass lens waste as an alternative soluble silica source for alkali-activation reactions

This research study was aimed at assessing the potential use of glass powder (GW), from the production of optical lenses, as a substitute of commercial sodium silicate (SS), to produce fly ash-based alkaline cements. The dissolution of the GW and the subsequent activation were achieved either with a cleaning solution (CS) from the aluminium casting industry, and a commercial sodium hydroxide solution (SH) so as to. Firstly, GW dissolution with CS and SH was evaluated at different time and temperatures, i.e.,16 h, 3, 7 and 28 days at 20 °C and 16 h at 20, 40, 60 and 80 °C, to find the best dissolution rate, which an optimum point was observed when CS was the dissolving agent. Then, several pastes were synthesized and cured for 7 days at 50 °C to assess their mechanical behaviour and alkaline-activated gel formation by compressive strength test. Furthermore, reaction products were characterized by X-ray diffraction (XRD) and electron microscopy (SEM/EDX). The observations reveal that although SH solution acted well to dissolve GW, so that the compressive strength was close to that of SS, CS also showed reasonable potential to be used as a dissolving agent for GW, rendering a cheap and environmentally friendly alternative activator. Microstructural analysis also illustrated the rise in the crystallinity of the reaction products obtained from industrial by-products, i.e., GW and CS.

Aristaeella hokkaidonensis gen. nov. sp. nov. and Aristaeella lactis sp. nov., two rumen bacterial species of a novel proposed family, Aristaeellaceae fam. nov.

Two strains of Gram-negative, anaerobic, rod-shaped bacteria, from an abundant but uncharacterized rumen bacterial group of the order 'Christensenellales', were phylogenetically and phenotypically characterized. These strains, designated R-7T and WTE2008T, shared 98.6-99.0 % sequence identity between their 16S rRNA gene sequences. R-7T and WTE2008T clustered together on a distinct branch from other Christensenellaceae strains and had <88.1 % sequence identity to the closest type-strain sequence from Luoshenia tenuis NSJ-44T. The genome sequences of R-7T and WTE2008T had 83.6 % average nucleotide identity to each other, and taxonomic assignment using the Genome Taxonomy Database indicates these are separate species within a novel family of the order 'Christensenellales'. Cells of R-7T and WTE2008T lacked any obvious appendages and their cell wall ultra-structures were characteristic of Gram-negative bacteria. The five most abundant cellular fatty acids of both strains were C16 : 0, C16 : 0 iso, C17 : 0 anteiso, C18 : 0 and C15 : 0 anteiso. The strains used a wide range of the 23 soluble carbon sources tested, and grew best on cellobiose, but not on sugar-alcohols. Xylan and pectin were fermented by both strains, but not cellulose. Acetate, hydrogen, ethanol and lactate were the major fermentation end products. R-7T produced considerably more hydrogen than WTE2008T, which produced more lactate. Based on these analyses, Aristaeellaceae fam. nov. and Aristaeella gen. nov., with type species Aristaeella hokkaidonensis sp. nov., are proposed. Strains R-7T (=DSM 112795T=JCM 34733T) and WTE2008T (=DSM 112788T=JCM 34734T) are the proposed type strains for Aristaeella hokkaidonensis sp. nov. and Aristaeella lactis sp. nov., respectively.

Transcriptomic Analysis Reveals the Response of the Bacterium Priestia Aryabhattai SK1-7 to Interactions and Dissolution with Potassium Feldspar.

Potassium feldspar (K2O·Al2O3·6SiO2) is considered to be the most important source of potash fertilizer. The use of microorganisms to dissolve potassium feldspar is a low-cost and environmentally friendly method. Priestia aryabhattai SK1-7 is a strain with a strong ability to dissolve potassium feldspar; it showed a faster pH drop and produced more acid in the medium with potassium feldspar as the insoluble potassium source than in the medium with K2HPO4 as the soluble potassium source. We speculated whether the cause of acid production was related to one or more stresses, such as mineral-induced generation of reactive oxygen species (ROS), the presence of aluminum in potassium feldspar, and cell membrane damage due to friction between SK1-7 and potassium feldspar, and analyzed it by transcriptome. The results revealed that the expression of the genes related to pyruvate metabolism, the two-component system, DNA repair, and oxidative stress pathways in strain SK1-7 was significantly upregulated in potassium feldspar medium. The subsequent validation experiments revealed that ROS were the stress faced by strain SK1-7 when interacting with potassium feldspar and led to a decrease in the total fatty acid content of SK1-7. In the face of ROS stress, strain SK1-7 upregulated the expression of the maeA-1 gene, allowing malic enzyme (ME2) to produce more pyruvate to be secreted outside the cell using malate as a substrate. Pyruvate is both a scavenger of external ROS and a gas pedal of dissolved potassium feldspar. IMPORTANCE Mineral-microbe interactions play important roles in the biogeochemical cycling of elements. Manipulating mineral-microbe interactions and optimizing the consequences of such interactions can be used to benefit society. It is necessary to explore the black hole of the mechanism of interaction between the two. In this study, it is revealed that P. aryabhattai SK1-7 faces mineral-induced ROS stress by upregulating a series of antioxidant genes as a passive defense, while overexpression of malic enzyme (ME2) secretes pyruvate to scavenge ROS as well as to increase feldspar dissolution, releasing K, Al, and Si into the medium. Our research provides a theoretical basis for improving the ability of microorganisms to weather minerals through genetic manipulation in the future.

Effect of Use of Potato Chips Waste as a Source of Easily Soluble Carbohydrates in Alfalfa Silage on Silage Quality.

This study was carried out to examine the effect of adding potato chips waste, which is a by-product of the potato processing industry, on silage quality, as an easily soluble carbohydrate source, to the alfalfa (Medicago sativa L.) plant, which has a high buffering capacity and is therefore difficult to ensilage. In the study, alfalfa (Medicago sativa) harvested at the 10% flowering point was used as the plant material. Four different groups were formed by adding the silage groups prepared in the study, alfalfa plant control (without additives), and potato chips waste at the rates of 0.5%, 1% and 2% on a wet weight basis to the alfalfa plants. The silages were opened at the end of the 60-day fermentation period and raw nutrient compositions and fermentation products were identified. When the effects of the silages prepared by adding different levels of chip waste to alfalfa plant on the nutrient value were examined, the differences between the groups in terms of dry matter (DM), crude ash (CA), acid detergent fiber (ADF) and neutral detergent fiber (NDF) content of the silages obtained from the study were statistically significant. While it was not significant in terms of CP content, the differences between the silage groups were found to be statistically significant. In the study, when the pH, ammonia nitrogen (NH3-N), carbon dioxide (CO2) production and total yeast mold values of the fermentation properties of the silages were examined, decreases were observed due to the addition of chips compared to the control group. When the total lactic acid bacteria (LAB) values of the silages were examined, an increase was observed after the addition of 1% chips. As a result, when all the parameters were examined, it was determined that the silages prepared by adding 1% chips waste had positive effects on silage fermentation.

Feasibility of membrane distillation brine assistant anaerobic fermentation for enhancing carbon migration and recovery from excess sludge: Two wastes into one resource

The carbon recovery from excess sludge has received rising attentions. This study developed an innovative membrane distillation (MD) brine assistant anaerobic fermentation. The Na+, instead of other ions in MD brine, disrupted O-H stretching and N-H/C-N stretches of amide I in proteins for loosening protein structure and reducing hydrophilic functional groups, which triggered considerable sludge disintegration and microbial cell lysis with plicated floc surface structure and organic fragment stripping. Thereby, the carbon sources of 785.90 mg/L were released, among which the tyrosine-like protein and soluble microbial by-products were identified as the crucial dissolved organic matters relating to enhancing anaerobic fermentation. As such, the volatile fatty acids (VFAs) production was improved to 1689.65 mg COD/L (55.93 mg C/g VSS) through 4-day MD brine assistant anaerobic fermentation, which was mainly composed by acetic and propionic acids (58.96–84.16%), while the acetoxylation was also facilitated by MD brine. Correspondingly, the carbon source biodegradation towards micromolecule shift was promoted, considerable carbon release and recovery rates of 18.27% and 13.31% were achievable, respectively. The VFAs and proteins were dominant soluble carbon sources, while the pretty high C/N of 10.4 was achieved in fermentation liquid, demonstrating the bio-availability of recovered carbon sources. The economic and carbon-emission reduction benefits of 167.94–412.26 CNY and 0.0726 ton CO2 were obtained by carbon recovery from each ton excess sludge solid.

A Comparison of Nitrate Release from Zn/Al-, Mg/Al-, and Mg-Zn/Al Layered Double Hydroxides and Composite Beads: Utilization as Slow-Release Fertilizers.

Nitrate-loaded Zn/Al, Mg/Al, and Mg-Zn/Al layered double hydroxides (LDHs) were synthesized using the coprecipitation method. The slow-release properties of LDHs were measured in powder form at various pH conditions. Sodium alginate was used to encapsulate Mg/Al LDH to produce composite beads (LB) to further slow down the release of nitrate ions. The prepared LDH samples and LB were characterized by X-ray diffraction, attenuated total reflectance Fourier transform infrared spectroscopy, thermogravimetric analysis, and inductively coupled plasma optical emission spectroscopy. The surface morphologies of LDHs and LB were obtained from scanning electron microscopy analysis. The slow-release properties of the materials were evaluated using a kinetic study of nitrate release in tap water, soil solution, as well as plant growth experiments using coriander (Coriandrum sativum). The nitrate release ability of LDHs and LB was compared with a soluble nitrate source. The plant growth experiments showed that all three LDHs were able to supply an adequate amount of nitrate to the plant similar to the soluble fertilizer while maintaining the availability of nitrate over extended periods. The ability of LDHs to increase soil pH was also demonstrated.

Enhancing volatile fatty acids accumulation through anaerobic co-fermentation of excess sludge and sodium citrate: Divalent cation chelation and carbon source supplement

This work developed an innovative anaerobic co-fermentation strategy of excess sludge to enhance volatile fatty acids (VFAs) production and carbon recovery relying on the sodium citrate (SC) functions of divalent cation bridging impairing and biodegradable substrate supplement. It was demonstrated that SC greatly improved rate constant and equilibrium performances of both sludge hydrolysis and VFAs accumulation, suggesting that the 0.4 g/g SS was the optimum SC dosage. The SC was partly absorbed in sludge solid and chelated structural divalent cations, which greatly facilitated sludge hydrolysis with the SCOD/TCOD of 28.20%. Meanwhile, the residual SC in liquid phase contributed to VFAs bio-generation as carbon substrates. Thereby, the VFAs accumulation was improved to 387.72 mg COD/g VSS in a short-term anaerobic co-fermentation (2 d), approximately 7.64 times higher than that without SC addition. The VFAs were mainly composed by acetate (58.86–81.76%) and propionate (7.97–16.28%). In the whole anaerobic co-fermentation process, remarkable carbon source of 1785.74 mg/L was released. Acetate was the dominant composition in total soluble carbon sources with the percentage of 44.45–83.98%, manifesting the bio-availability of fermentative liquid. In this case, the bio-available carbon recovery rate of 38.04% was achieved. Moreover, mechanism of the enhanced anaerobic co-fermentation was illustrated and the economic benefits were clarified.

Rice husk ash as an alternative soluble silica source for alkali-activated metakaolin systems applied to recycled asphalt pavement stabilization

Alkali-activated binders have been shown as a viable alternative do ordinary Portland cement. However, the development of lower carbon emission activators for this process is still a research-gap. The goal of this research was to analyze the stabilization of recycled asphalt pavement (RAP) mixtures with a metakaolin-based binder, alkali-activated by rice husk ash synthetized sodium silicate. Compaction, unconfined compressive strength (UCS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) tests were conducted in stabilized RAP mixtures, submitted to different curing periods and temperatures. Also, results were correlated with the porosity/binder content index. Compaction results showed a reduction in dry unit weight as the RAP content increased for non-stabilized mixtures and a non-linear behavior for stabilized ones. For the UCS tests, the increase in binder content led to an increase in strength for all mixtures. High curing temperatures prevented the efflorescence phenomenon, however reduced strength due to crack formation. XRD analyzes showed the formation of minerals rich in silica and alumina, indicating the formation of geopolymerization products. Finally, the porosity/binder index was shown to be a viable dosage method to predict the strength of stabilized RAP mixtures.

Impacts of co-contaminants and dilution on perchlorate biodegradation using various carbon sources.

This research investigates the biodegradation of perchlorate in the presence of the co-contaminants nitrate and chlorate using soluble and slow-release carbon sources. In addition, the impact of bio-augmentation and dilution, which results in lower total dissolved salts (TDS) and contaminant levels, is examined. Laboratory microcosms were conducted using actual groundwater and soils from a contaminated aquifer. The results revealed that both soluble and slow-release carbon sources support biodegradation of contaminants in the sequence nitrate > chlorate > perchlorate. Degradation rates, including and excluding lag times, revealed that the overall impact of the presence of co-contaminants depends on degradation kinetics and the relative concentrations of the contaminants. When the lag time caused by the presence of the co-contaminants is considered, the degradation rates for chlorate and perchlorate were two to three times slower. The results also show that dilution causes lower initial contaminant concentrations, and consequently, slower degradation rates, which is not desirable. On the other hand, the dilution resulting from the injection of amendments to support remediation promotes desirably lower salinity levels. However, the salinity associated with the presence of sulfate does not inhibit biodegradation. The naturally occurring bacteria were able to support the degradation of all contaminants. Bio-augmentation was effective only in diluted microcosms. Proteobacteria and Firmicutes were the dominant phyla identified in the microcosms.

Nutrient digestibility in broiler chickens fed diets containing high levels of soybean oil is affected by the source of fiber

This study evaluated the effects of including soluble and insoluble dietary fiber sources in soybean oil-containing diet for broiler chickens on coefficient of apparent ileal digestibility (AID) of amino acids, coefficient of apparent retention (AR) of nutrients, and nitrogen-corrected apparent metabolizable energy (AMEn). A total of 180 broilers were divided into 30 groups and fed 3 diets from day 14 to 21 of age. The diets were corn–soybean meal containing 6.8% soybean oil without or with soybean hulls (SBH) or sugar beet pulp (SBP) at 8.0% as sources of insoluble and soluble fiber, respectively. The SBH and SBP contained 6.0% and 14.7% of soluble dietary fiber and 60.5% and 37.0% of insoluble dietary fiber, respectively. The AID of indispensable amino acids was decreased ( P &lt; 0.05) due to dietary inclusion of SBH, but not of SBP. Dietary SBH and SBP reduced the AR of gross energy (by 14% and 8%, respectively) and AMEn (by 20% and 14%, respectively). Overall, inclusion of SBH or SBP at 8.0% in a corn–soybean meal-based diet for broilers that contains high level of soybean oil might not improve nutrient digestibility. However, SBP has less detrimental effects on nutrient digestibility than SBH.