响应面法优化带鱼下脚料酶解物螯合锌的制备工艺

为优化带鱼下脚料酶解物和锌离子的螯合工艺条件,以带鱼加工下脚料为原料,在单因素试验的基础上,采用Box-Behnken中心组合设计和响应面分析法,探讨酶解物与硫酸锌的质量比、酶解物浓度、p H、反应温度、反应时间等因素对酶解物锌螯合反应的影响。结果表明,带鱼下脚料酶解物螯合锌的最适条件为:质量比4.5∶1,p H值6.0,酶解物浓度4%,反应温度50℃,反应时间40 min,在此条件下螯合率达到84.16%,与模型预测值相符。该螯合工艺反应条件温和,锌螯合率高。本研究为锌螯合物的制备以及带鱼下脚料的高值化利用提供了理论依据。     

细点圆趾蟹肉酶解肽螯合锌工艺的优化

为了优化蟹肉酶解肽的锌螯合工艺,以细点圆趾蟹肉为原料,制得蟹肉酶解物,通过单因素试验,考察酶解物与硫酸锌的质量比、pH、反应时间、酶解物浓度、反应温度对锌修饰蟹肉酶解肽的影响,采用正交试验优化蟹肉酶解肽的锌修饰工艺。结果表明,在酶解物与硫酸锌的质量比2∶1、pH值6.5、时间60 min、酶解物浓度5%、温度55℃条件下,酶解肽-锌的螯合率为91.52%,螯合物得率为25.83%,该工艺条件下酶解肽与锌的螯合率和螯合物得率均较高。本研究结果为新型生物态锌的研制、细点圆趾蟹的高值化利用提供了依据。     

利用废革屑制备肽Ca螯合物的工艺探究

本论文通过水解革屑制备多肽水解液,并将水解液与Ca Cl2进行螯合反应制备多肽-Ca金属螯合物。对水解液进行理化性能进行表征,利用GPC测定水解液的分子量;设计单因素螯合实验及正交试验,考察了p H、温度、时间、肽/Ca质量比等因素对螯合反应的影响,确定了最佳反应条件。通过研究发现不同因素对螯合率的影响大小为:温度时间肽Ca比 pH;对得率的影响大小为:pH温度肽Ca比时间。最佳螯合条件:反应时间90 min,肽Ca比为4∶1,反应温度为70℃,pH为7,最佳条件下的螯合率为86.55%;最后,对肽Ca螯合物进行傅里叶红外光谱、扫描电镜及能量色散X射线光谱仪分析表征,结果表明Ca离子成功螯合到多肽上,得到Ca肽螯合物。     

复合氨基酸微量元素螯合肥制备工艺研究

以废弃鸡毛水解液为复合氨基酸来源,研究其与微量元素铁、锌、锰、铜螯合的最佳工艺条件,并利用有机溶剂沉淀分离法制备固体复合氨基酸亚铁、锌、锰、铜螯合物,以螯合率为指标考察影响制备工艺的主要因素。结果表明,最佳工艺参数为:复合氨基酸与亚铁、锌、锰和铜螯合反应的最佳配位体摩尔比均为2∶1;最佳pH值范围分别为5.0、8.0、4.0～5.0和6.0～7.0;反应温度为室温(222～6℃);反应时间为30.min。在上述条件下,复合氨基酸与各微量元素的螯合率均超过95%;所得复合氨基酸螯合物可与0.2.mol/L磷酸二氢钾复配,克服了传统微肥完全不能与磷酸盐复配的缺陷。     

钙螯合羊骨胶原多肽的制备及表征分析

为制备肽钙螯合物并探明肽钙螯合机理,对羊骨胶原多肽与CaCl2的螯合工艺进行优化并对肽钙螯合物进行表征分析。采用Box-Behnken中心组合设计及响应面分析法,确定了最佳螯合参数：肽钙质量比2∶1,pH值7.66,53℃螯合50 min,螯合率达67.24%。红外光谱、电镜分析及能谱扫描结果表明胶原多肽与Ca2+分别在多肽内部的C=O处及肽链末端的-NH2和-COOH处发生螯合,形成了铵盐和羧酸盐;多肽与Ca2+螯合后由疏松的片状结构变成了致密的小颗粒聚集体结构。红外光谱及能谱扫描同时也证实所制备的胶原多肽中有部分钙螯合肽的存在,说明酶解可使钙由羟基磷灰石形式转变为可溶性离子钙。研究结果可为新型钙制剂生产及畜骨的高值利用提供了参考。     

氨基酸与锌配合喷施提高小白菜生物量、品质及锌利用效率

【目的】 作物可以直接吸收小分子有机氮,探究不同氨基酸对作物产量、品质及养分吸收的影响,及其与锌肥配合的效果可深化对有机营养的认识,为叶面施肥提供理论依据。【方法】 以小白菜为供试作物进行盆栽试验,以喷施清水为对照,设甘氨酸、谷氨酸、苏氨酸、七水合硫酸锌分别单独喷施和甘氨酸、谷氨酸、苏氨酸分别与七水合硫酸锌混合喷施处理,三种氨基酸浓度梯度均为100、250、400 mg/L,七水合硫酸锌施用浓度为0.1%,共20个处理;每个处理5次重复,随机区组排列;收获后测定植株生物量和硝酸盐、可溶性糖及维生素C含量,分析植株吸收锌量。【结果】 1）施用三种氨基酸均能明显促进小白菜生长、改善品质,并能显著促进小白菜对锌的吸收。与对照相比,喷施三种氨基酸小白菜生物量分别提高了32.0%、19.8%和16.6%,硝酸盐含量分别降低了53.9%、60.9%和65.6%,可溶性糖含量分别提高了66.2%、145.1%和207.6%,Vc含量分别提高了20.8%、38.8%和61.6%。喷施100 mg/L的甘氨酸小白菜锌吸收量提高了12.0%,而喷施三种浓度的谷氨酸与苏氨酸均可提高小白菜的锌吸收量,分别平均提高了38.7%、12.0%;2）甘氨酸、谷氨酸、苏氨酸与硫酸锌混合喷施可明显提高锌的应用效果,与硫酸锌单施相比,混合喷施可分别使小白菜生物量提高25.6%、25.4%和24.5%,硝酸盐含量降低19.0%、26.3%和25.2%,可溶性糖含量提高33.2%、72.7%和27.1%,Vc含量提高67.1%、22.6%和25.2%,锌吸收量提高26.7%、50.0%和67.8%,锌利用率分别提高了14.3%、10.2%和19.2%,差异显著。【结论】 甘氨酸、谷氨酸、苏氨酸单独施用或与硫酸锌混合施用均能明显促进小白菜的生长发育及对锌的吸收利用,并能显著改善其品质。甘氨酸、谷氨酸、苏氨酸单独施用或与硫酸锌混合喷施其最适浓度范围均分别为250~400 mg/L、250~400 mg/L、100~250 mg/L。苏氨酸与硫酸锌混合喷施应用效果较甘氨酸和谷氨酸更佳,在氨基酸螯合锌肥中可优先选用。     

猪骨粉制备胶原多肽螯合钙工艺优化

为了充分利用猪骨资源,该文以猪骨粉为原料,研究了胶原多肽螯合钙的制备工艺。首先利用乳酸菌发酵酶解猪骨粉,以发酵液中游离钙含量为指标,确定最佳发酵条件为：蔗糖添加量7%,温度35℃,转速120 r/min,接种量12%,发酵时间18 h。对发酵液进行浓缩后,再与胶原多肽溶液进行螯合,通过单因素和响应面试验,确定螯合的最优条件为：pH值7.9,温度40℃,胶原多肽溶液与发酵液体积比为7∶1,螯合时间 4 h,无水乙醇添加倍数为11,此时螯合率为79.9%,为猪骨的深入开发提供依据。     

螯合态与离子态微量元素在花生种衣剂中的作用初步研究

通过田间试验比较了螯合态与离子态微量元素在花生种衣剂中的作用效果。试验结果表明,螯合态与离子态微量元素在花生种衣剂中作用效果差异不显著;离子态微量元素略优于螯合态微量元素;种衣剂中加入1％的离子态锌素或加入1％的离子态锌及1％的离子态铁均能够增产增收。     

利用螯合–缓冲营养液对小麦苗期磷–锌关系的研究

采用螯合缓冲营养液培养技术（Chelator-buffer culture solution）,对小麦幼苗植株的磷锌营养进行了探讨。结果表明,高磷条件下小麦出现的缺锌黄化与磷中毒症状之间存在着明显区别,本研究结果支持高磷条件下作物出现的黄化是锌缺乏症状而非磷中毒的观点。与缺磷相比,正常供磷促进了小麦的生长,但过量磷对小麦生长有阻碍作用,而且锌的供应加剧了促进或抑制的程度。正常供应磷、锌条件下,小麦幼苗根系或地上部的磷、锌含量、吸收量及转运率均处于相对较高的水平,其余各处理则因为磷或锌供应量不适宜而使植株的磷、锌营养受到不同程度的影响。另外,磷锌相互拮抗的作用方式及大小程度不同:磷主要影响小麦根系对锌的吸收,而锌对小麦磷营养的影响主要是通过对其从根系向地上部转运的抑制来实现的;磷对锌的影响要明显大于锌对磷的影响,磷素水平在小麦的磷、锌营养平衡中起着更为重要的作用。磷锌拮抗作用只在双方供应不适宜的情况下发生,而且相互作用的方式及程度存在明显差异。     

山梨醇螯合钙对NaCl胁迫下油菜种子萌发的影响

本文通过控制钙源种类(螯合态钙和游离态钙)、两种形态钙配比(不同螯合率)及螯合态钙浓度等3组试验探究山梨醇螯合钙对NaCl胁迫下油菜种子萌发的影响.结果表明:当培养液中NaCl浓度为150或170 mmol/L时严重影响油菜种子的萌发和胚根生长,添加两种形态钙后均能显著提高NaCl胁迫下种子活力和发芽率,促进胚根的生长...     

Effect of carbon dioxide on the stability of iron chelates

The effect of carbon dioxide partial preassure on the stability of iron chelates in calcareous soils is often laid aside. Theoretical stability diagrams have been developed showing the large importance of this compound on total iron solubility from Fe‐EDTA and ‐DTPA chelates. As CO₂ increases free Ca²⁺ activity in solution decreases. Then chelation of iron increases. CO₂ partial preassure does not change the stability of Fe‐EDDHA since percentage of chelation is 100% in all conditions tested for this chelate.

Experimental data fit theoretical diagrams well when CO₂ partial preassure is high, but when CO₂ ^‐free air is used, chelation is greater than expected. Causes that can produce this difference are discussed.     

Preparation and Optimization of Amino Acid Chelated Micronutrient Fertilizer by Hydrolyzation of Chicken Waste Feathers and the Effects on Growth of Rice

For the preparation of amino acid chelated fertilizer, chicken feathers were hydrolyzed with sulfuric acid (H₂SO₄; 6M) and potassium hydroxide (KOH; 6M) separately in the presence of different catalysts. Under acidic conditions, the catalyst zinc sulfate, gave minimum ammonium but a maximum conversion rate of organic nitrogen (N) into amino acids (19% higher than control). Under alkaline conditions, sodium sulfide showed maximum amino acid-N and conversion rate (37% higher than control). The catalyst doses showed a continuous increase in the conversion rate and were highest at 12%. The ratio of 1:3 feathers: hydrolytic agent showed maximum conversion rate. Hydrolytic time had a nonsignificant effect under acidic conditions, but under alkaline conditions a hydrolytic time of 14 h gave the maximum conversion rate. The chelation experiment results showed that the ratios (2:1, 2.5:1, and 3:1) showed almost equal chelation rates, except the 1:1 ratio of hydrolysis product to salt. Iron (Fe), copper (Cu), and manganese (Mn) showed maximum chelation rates under acidic pH, while zinc (Zn) showed maximum chelation rate at an alkaline pH. Temperature and chelation time had a nonsignificant effect on chelation rate. Comparative study results of amino acid chelated Zn and Fe fertilizers, ethylenediaminetetraacetic acid (EDTA) chelated Zn and Fe fertilizers, and zinc sulfate (ZnSO₄) and iron sulfate (FeSO₄) fertilizer foliar application to upland rice showed that a 1/100 dilution of amino acid chelated Zn and Fe fertilizers increased growth parameters from 22–73%, while EDTA chelated Zn and Fe fertilizers caused an increase of 15–63%, and ZnSO₄ and FeSO₄ increased growth parameters from 11–35% over the control. After fertilizer application, increase in chlorophyll contents was 11–17%, 3–6%, and 8–12%, respectively, over control. Therefore, amino acid chelated micronutrient fertilizer is used in small amounts, has a low cost, and high rates of return.     

Kinetic behavior of Fe(o,o-EDDHA)-humic substance mixtures in several soil components and in calcareous soils

Ferric ethylenediamine- N, N'-bis-(o-hydroxyphenylacetic)acid chelate (Fe(o, o-EDDHA)) is one of the most effective Fe fertilizers in calcareous soils. However, humic substances are occasionally combined with iron chelates in drip irrigation systems in order to lower costs. The reactivity of iron chelate-humic substance mixtures in several soil components and in calcareous soils was investigated through interaction tests, and their behavior was compared to the application of iron chelates and humic substances separately. Two commercial humic substances and two Fe(o, o-EDDHA) chelates (one synthesized in the laboratory and one commercial) were used to prepare iron chelate-humic substance mixtures at 50% (w/w). Various soil components (calcium carbonate, gibbsite, amorphous iron oxide, hematite, tenorite, zincite, amorphous Mn oxide, and peat) and three calcareous soils were shaken for 15 days with the mixtures and with iron chelate and humic substance solutions. The kinetic behavior of Fe(o, o-EDDHA) and Fe non-(o,o-EDDHA) (Fe bonded to (o,p-EDDHA) and other polycondensated ligands) and of the different nutrients solubilized after the interaction assay was determined. The results showed that the mixtures did not significantly reduce the retention of Fe(o, o-EDDHA) and Fe non-(o,o-EDDHA) in the soil components and the calcareous soils compared to the iron chelate solutions, but they did produce changes in the retention rate. Moreover, the competition between humic substances and synthetic chelating agents for complexing metal cations limited the effectiveness of the mixtures to mobilize nutrients from the substrates. The presence of Fe(o, p-EDDHA) and other byproducts in the commercial iron chelate had an important effect on the evolution of Fe(o, o-EDDHA) and the nutrient solubilization process.     

Water Lettuce Pistia stratiotes L. Response to Lead Toxicity

The effects of one of the most toxic heavy metals, lead (Pb), applied in two different concentrations and combined with chelate application were investigated on the water macrophyte (Pistia stratiotes L.) physiology. The influences were observed by the chlorophyll and free amino acid content determination. Also the lead accumulation in macrophyte biomass was investigated to assess the potential efficiency of this plant for rhizofiltration of highly Pb-polluted water. Na EDTA and Na citrate were used as chelates and Pb(NO₃)₂ as lead supplement. The application of organic chelates simulated conditions of an induced phytoextraction process. Statistical analyses were performed as a one-way ANOVA with a subsequent Tukey HSD test at a level of P < 0.05. Pb contents in both root and leaf tissues gradually increased with increasing Pb concentrations in the nutrient solution. More lead was accumulated in leaves than in roots within all treatments. The total chlorophyll content decreased with increased Pb concentration and with a higher content of chelates. The chelate addition increased the total amino acid content in leaves but decreased the total amino acid content in roots. The addition of lead with chelates decreased the dry biomass weight. However, water macrophyte showed extremely high lead accumulation in biomass in the short term (up to 8 days) and this accumulation potential could be used for relatively fast and effective decrease of high concentration of this risk element in contaminated water or sewage.     

Kinetics of reactions of chelates FeEDDHA and FeEDDHMA as affected by pH and competing ions

Abstract

Iron chelates are widely used in fertigation because of their high stability and solubility. However, sudden changes of pH or concentrations of accompanying ions affect chelate stability and make kinetics as relevant as equilibrium data. The kinetics of FeEDDHA and FeEDDHMA reactions at acidic pH values in the presence and absence of calcium (Ca), magnesium (Mg), phosphorus (P), copper (Cu), nickel (Ni), and zinc (Zn) were studied. The FeEDDHA and FeEDDHMA decompound in few seconds at low pH values. The extension of the decomposition reaction is affected by the kind of chelate and concentration. Calcium, Mg, P, Cu, and Zn slightly slow down the reaction. The recovery of both chelates is observed when pH increases. The reaction is quick and practically complete in absence of competing ions, although the percentage of recompound chelate is affected by the chelating agent and pH. FeEDDHMA recompounds in a larger extension than FeEDDHA. The percentage of recompound chelate increases from pH 4 to 7. The rate of reaction and the quantity of recompound chelate are not modified by the presence of Ca or Mg ions. However, phosphate diminishes the percentages of recovery, and its effect is larger as higher is the relationship [P]/[chelate]. The occurrence of Cu, Ni, manganese (Mn), and Zn slows down the reaction at low chelate concentrations. They also decrease the percentage of recompound chelate. The negative effect of the microelements is higher on the recovery of FeEDDHMA than on FeEDDHA, but for both chelates, the influence of the competing ions diminishes as the chelate concentration increases. Copper has the greatest impact on the recomposition of the chelates FeEDDHA and FeEDDHMA, although Ni, a high concentrations, can end up impeding the recovery of FeEDDHMA.     

Interaction of iron chelates with several soil materials and with a soil standard

Frequently the effectiveness of iron (Fe) chelates is low because they can be retained or destroyed by soil materials. The high cost of these Fe fertilizers makes it necessary to study soil material reaction with Fe chelates. Commercial Fe chelates with EDTA, EDDHA, and EDDHMA as ligands and their standards, prepared in the laboratory, were shaken for one hour with various soil materials [amorphous Fe(III) oxide, acid peat, calcium (Ca)‐montmorillonite and calcium carbonate (CaCO₃)] and with a soil standard made in the laboratory. After agitation, the chelate‐soil mixtures were filtered and the micronutrients and chelated Fe that remained in solution were determined. Among the soil materials used, amorphous Fe(III) oxide and acid peat had the greatest affect on the amount of chelated Fe remaining in solution. The type of chelating agent was the next major factor that affected the availability of soluble Fe following reaction with the soil materials. Another factor was the commercial formulation of the Fe chelates. The chelates comprised of EDDHA or EDDHMA maintained the highest percentages of chelated Fe in solution after interaction with the solid phases, except for the acid peat. The last soil material, acid peat, retained more chelated Fe for the Fe chelates with EDDHA or EDDHMA than with EDTA as the chelating agent. The commercial Fe‐EDDHA chelates had greater losses of chelated Fe than their standard after interaction with all the solid phases. The commercial Fe‐EDDHA chelate (Sequestrene) and the commercial Fe‐EDDHMA chelate (Hampirón) solubilized the highest amount of copper (Cu) from soil standard. This was attributed to the presence of by‐products in the commercial formulations since the Fe‐EDDHA standard did not have Cu in solution after the interaction. Therefore, the commercial Fe chelate by‐products are able to form Cu‐complexes which could affect chelated Fe and its availability to plants.     

Amelioration of aluminum toxicity to sorghum seedlings by chelating agents

At the pH levels found in acid soils (4.5 to 5.5), theoretical equilibrium models predict that Al will be complexed on a nearly one to one molar basis by NTA, EGTA. oxalate (OX) and citrate (CIT). Growth chamber experiments were initiated using solutions containing Al (0, 2, or 10 μM), Ca (400 μ.M). and a chelate (0 or 10 μM) growing sorghum [Sorghum bicolor (L.) Moench cv. AT×399 × RT×430] for four days following germination to test the equilibrium models. The pH and concentration of Al in the solutions were measured before and after each experiment. Plant root length and weight, and shoot weights were used as a bioassay for the uncomplexed, toxic Al. Root length showed the greatest response to aluminum and chelate treatments, although root weight and shoot weight gave the same general results. Chelate effectiveness in reducing Al toxicity was NTA > OX = CIT > EGTA. The pH values were altered very little by NTA or EGTA and averaged 5.2 to 5.3; however, the pH was raised 0.2 to 0.9 units by OX and CIT. Thus, some detoxifying effect from the latter two could be a pH effect. No chelate effect was evident at pH values near 6 for CIT, but the chelate was effective in reducing Al toxicity at pH 5.6, indicating the importance of pH in Al toxicity. NTA alone did not affect root length, but the other chelates all decreased root length to a small degree at 0 μM Al indicating that the chelate itself was detrimental to growth. It was concluded that NTA was an effective chelate to detoxify Al and EGTA was not. Also it was found that OX and CIT behave quite differently from NTA and EGTA in that they affect pH and lower solution Al concentration. The method did not confirm the equilibrium models for EGTA, OX, or CIT because of complicating factors such as pH variation and damage to the roots by the chelates. The equilibrium model for NTA, though, was confirmed.     

Efficiency of GAC for Treatment of Leachate from Soil Washing Process

Granular activated carbon (GAC), granular activated alumina (GAA) and a ferric chloride solution (FCS) were tested for the treatment of leachate contaminated by heavy metals. The leachate was collected following the remedation of soils using weak organic acids and/or their salts, EDTA and DTPA. Only GAC was found to effectively remove heavy metals (Cd, Cu, Cr, Hg, Mn, Pb and Zn as chelates) from the leachate. At optimum pH ranging from 5.4 to 6.9, 97% of Hg was removed while at optimum pH ranging from 6.9 to 7.7, 78 to 96% of Cd, Cu, Mn, Pb and Zn were removed. Some 77% of the Cr was removed at optimum pH of 5.4. Adsorption rate constant and Langmuir adsorption capacity of GAC were found to be 0.01 min^?1 and 19 mg metal chelate g^?1 of GAC, respectively. Freundlich constants, k and n were found to be 21 mg g^?1 and 2.778, respectively. The brown color of the leachate turned colorless after GAC treatment.

     

Characterization of commercial iron chelates and their behavior in an alkaline and calcareous soil

Iron deficiency is a common problem for many plants grown in alkaline and calcareous soils. To correct this problem, iron is supplied to plants as chelates. Several iron chelates are sold under diverse trademarks with different characteristics. This work evaluated 18 commercial products containing the most representative chelated iron sources used in agricultural practice in Spain when the study was done, namely the ferric chelates of EDDHA, EDDHMA, EDDCHA, EDDHSA, EDTA, and DTPA. The chelates were comprehensively characterized and quantitated by several techniques, including several chromatographic methods. Iron and chelate dynamics in soil were also studied in a model alkaline and calcareous soil. Results indicate that, in this model soil, among the different iron compounds studied only FeEDDHA and analogues have the capacity to maintain soluble iron in soil solution over time. These results are in agreement with general experience under field conditions. Furthermore, among the different ortho-ortho isomers of FeEDDHA's, FeEDDHSA and FeEDDCHA showed greater capacity than FeEDDHA and FeEDDHMA to maintain the chelated iron in soil solution over time.