Characterization of Organic Acids Recovered from Rhizosphere of Corn Grown on Biosolids‐Treated Medium

Abstract

Organic acid production by plants and microorganisms was quantified in sand media amended with biosolids in the presence and absence of corn (Zea mays L.) in a sand‐culture hydroponic medium. Total quantities of organic acids were greatest in treatments containing both plants and biosolids, with lesser amounts in treatments with plants alone, biosolids‐treated media alone, and a nutrient solution–irrigated blank medium. Biosolids enhanced organic acid production in the rhizosphere and influenced the composition of organic acid mixtures. Only lactic, acetic, butyric, and oxalic acids were detected in media without plants. When the medium was planted, additional organic acids were recovered including tartaric, maleic, succinic, valeric, glutaric, pyruvic, and propionic. Lactic, acetic, and butyric acids were predominant in solutions recovered from the planted media and collectively accounted for 0.65 to 0.75 of the COO^? mole fraction. Oxalic, maleic, and tartaric acids were the second most abundant and varied from 0.05 to 0.1 of the mole fraction, followed by succinic, valeric, glutaric, propionic, and pyruvic acids, comprising ≤0.05 of the mole fraction. Plant growth stage had no effect on relative proportions of organic acids but did influence the total quantities of organic acids recovered. Biosolids sources did not have a significant effect on either the quantity or composition of organic acids in any media. The predominance of organic acids that are microbial fermentation products suggests that the carbon contained in root exudates and biosolid amendments was transformed into a mixture of various fermentation products that accumulated in the rhizosphere solution and sand medium as a result of microbial growth and activity.     

The effect of SO2 on the production of ethanol,acetaldehyde, organic acids,and flavor volatiles during industrial cider fermentation

SO(2) is widely used in cider fermentation but also in other alcoholic beverages such as wine. Although the authorized limit is 200 ppm total SO(2), the International Organizations recommend its total elimination or at least reduction due to health concerns. Addition of SO(2) to apple juice at levels frequently used in industrial cidermaking (100 mg/L) induced significantly higher acetaldehyde production by yeast than that obtained without SO(2). Although the practical implications of acetaldehyde evolution under cidermaking conditions has been overcome by research and few data are available, this compound reached levels in two 2000 L bioreactors that may have prevented the occurrence of simultaneous alcoholic and malolactic fermentation. It was observed that malolactic fermentation had a positive effect promoting reduction of acetaldehyde levels in cider fermented with juice, SO(2)-treated or not. The addition of SO(2) clearly delayed malolactic fermentation comparing to the control, affecting not the onset of the malolactic fermentation but the rate of malic acid degradation. This compound, however, had a stimulatory effect on alcoholic fermentation.     

大豆和小麦对矿物钾的活化作用研究

大豆、春小麦均能有效地活化利用白云母、钾长石中的结构性钾,结构钾释放量为19.53mg kg-1~45.46mg kg-1。春小麦和大豆根系分泌的有机酸主要为草酸、酒石酸和柠檬酸,其次为乳酸、乙酸和苹果酸。草酸溶液酸性较强,络合能力也强,其活化钾的能力最强。苹果酸、酒石酸、柠檬酸、乙酸和乳酸亦可有效地促进白云母和钾长石的分解,但活化土壤钾的能力比较低。低分子量有机酸作用下矿物钾的释放是酸性水解和络合溶解双重作用的结果。草酸、酒石酸、柠檬酸是影响大豆、春小麦吸收利用矿物钾的主要低分子量有机酸。     

Anthocyanins, phenolics, and color of Cabernet Franc, Merlot, and Pinot Noir wines from British Columbia.

Changes in phenolics (anthocyanins, flavonols, tartaric esters, and total phenolics) during ripening of grapes and in phenolics and color during vinification and aging of Cabernet Franc, Merlot, and Pinot Noir wines were studied. Anthocyanins in grape skins showed variations in accumulation pattern, concentration, and distribution depending on variety and to a lesser extent on season. During vinification, colorless phenolics increased during alcoholic fermentation, reached maximum values at pressing, and remained stable during malolactic fermentation and subsequent storage. Anthocyanins and color density, on the other hand, increased during the early stages of alcoholic fermentation, reached maximum values 2-3 days after the start of fermentation, decreased during malolactic fermentation, and slowly declined during subsequent storage. Viticultural practices that increased cluster sun exposure generally led to higher phenolics and color density of wines, whereas changing yeasts used for fermentation had minimal effects.     

饼肥中的有机营养物质及其在发酵过程中的变化

分析测定了在恒温、恒湿条件下 4种植物油饼发酵过程中有机物质的变化。结果表明 ,由于不同植物油饼化学组成不同在发酵过程中所产生有机营养物质的成分和数量存在较大差异。发酵过程所产生的高级脂肪酸以C18、C16酸为主 ,并且不饱和脂肪酸的含量明显高于饱和脂肪酸 ;有机酸则以乳酸、苹果酸、柠檬酸、琥珀酸、酒石酸、乙酸含量较高 ,草酸含量较低 ;氨基酸则以谷氨酸含量最高 ,天门冬氨酸、亮氨酸和精氨酸含量次之。有机酸和高级脂肪酸含量随发酵时间的增加而增加 ,腐熟到一定程度时达到最高 ;而饼肥发酵 70d时各种氨基酸含量明显降低。 4种饼肥相比 ,豆饼和花生饼在发酵过程中氨基酸产生量大于芝麻饼和菜籽饼。从速度来看 ,芝麻饼腐熟最快 ,其次是豆饼 ,再次是花生饼 ,菜籽饼腐熟最慢。     

玉米浆发酵产生物丁醇的氨基酸代谢动力学模拟

为了深入挖掘利用丙酮丁醇梭菌产生物丁醇过程中氨基酸代谢的动态过程，探究利用廉价氮源玉米浆中的氨基酸用于丙酮丁醇梭菌产生物丁醇的生产策略，寻找生产丁醇的高效率廉价氮源来降低发酵生产成本。该研究首先利用高通量测序技术对玉米浆中微生物多样性进行分析；同时基于丙酮丁醇梭菌（Clostridium acetobutylicum）生产丙酮-丁醇-乙醇（Acetone-Butanol-Ethanol，ABE）碳代谢动态模型的基础上，构建氨基酸代谢模型，以此模拟15种氨基酸在利用木糖为碳源发酵生产ABE中的氨基酸代谢过程，并对氨基酸的代谢与丙酮丁醇梭菌的生物量以及ABE的合成相关性关系进行冗余分析；通过模型预测实际生产中利用玉米浆发酵时氨基酸的消耗过程。结果表明，梭状芽胞杆菌属（Clostridium）占细菌总数的68.76%，是玉米浆中的优势菌群；最佳参数校正后构建了氨基酸代谢模型，模拟值与试验值有较好拟合度；11种氨基酸（苯丙氨酸、苏氨酸、异亮氨酸、亮氨酸、蛋氨酸、缬氨酸、酪氨酸、甘氨酸、丝氨酸、精氨酸、天冬酰胺）在培养过程中迅速消耗用于细胞生长和溶剂生成，3种氨基酸（脯氨酸、组织胺、天冬氨酸）保持稳定状态，同时发酵过程中谷氨酰胺积累；冗余分析表明其中5种氨基酸对发酵产物及生物量影响具有相关性（P<0.05），相关性排序从大到小依次为丝氨酸、甘氨酸、亮氨酸、缬氨酸、天冬酰胺；模拟预测玉米浆中缬氨酸、甘氨酸、丝氨酸在发酵过程中基本被消耗，推测其为发酵后期的营养限制性因子。该结论可证实玉米浆可作为丙酮丁醇梭菌发酵丁醇的优势氮源，为丙酮丁醇梭菌的氨基酸代谢调控及下一步利用并优化玉米浆作为氮源生产生物丁醇提供一定的理论参考和数据支撑。     

In vitro interaction between ochratoxin A and different strains of Saccharomyces cerevisiae and Kloeckera apiculata

The interaction of ochratoxin A (OTA) and 20 yeast strains of Saccharomyces cerevisiae and Kloeckera apiculata during alcoholic fermentation was studied. Levels of OTA were determined in the fermentation liquid and in the yeast cells solid using a high-performance liquid chromatography system with a fluorescence detector. Yeast cells do not adsorb OTA, and for all yeasts, OTA levels did not affect the alcoholic fermentation. Some yeast strains reduced levels of OTA, whereas other strains did not show any effect demonstrating that OTA level reduction is not a genus species characteristic but a strain trait.     

Determination of organic acids by high-performance liquid chromatography with electrochemical detection during wine brewing

Voltammetric determination of acids by means of the electrochemical reduction of quinone was applied to high-performance liquid chromatography (HPLC) with electrochemical detection (ED) for determining organic acids in fruit wines. A two-channel HPLC-ED system was fabricated by use of an ion-exclusion column and an electrochemical detector with a glassy carbon working electrode. Aqueous solution of 0.1 mM HClO(4) and ethanol containing 2-methyl-1,4-naphthoquinone served as a mobile phase and reagent solution, respectively. Determination of acetic, citric, lactic, malic, succinic, and tartaric acids was made by measuring the peak areas of the flow signals due to the reduction current of quinone caused by the eluted acids. The peak area was found to be linearly related to the acid amount ranging from 0.1 to 40 nmol per 20 microL injection. The present method was characterized by reproducibility with the simple and rapid procedure without derivatization of analytes. The method was shown as an effective means for following acid contents in fruit juices during fermentation with wine yeast.     

Enhancement effect study of some organic acids on the calcium availability of vegetables: application of the dynamic in vitro simulated gastrointestinal digestion method with continuous-flow dialysis

The effect of added organic acids on the calcium availability of vegetables was investigated using the dialysis profiles obtained from an in vitro simulated gastrointestinal digestion with continuous-flow dialysis method. Citric acid was the most effective enhancer followed by tartaric, malic, and ascorbic acids. For amaranth, which has a low calcium availability (5.4%), a significant increase of availability was observed with increasing concentrations of all acids studied. With the continuous-flow dialysis approach, organic acids could be observed to promote the dialyzability even at an elevated intestinal pH. An enhancement effect from added organic acids was not clearly observed for Chinese kale, which itself contains a high amount of available calcium (52.9%).     

预发酵方式对餐厨垃圾酸化抑菌及甲烷发酵的影响

餐厨垃圾水分和有机物含量高,在收集储运过程中易酸腐变臭,影响其资源化利用。该文在新鲜餐厨垃圾中分别接种酵母菌和乙酸菌进行乙醇和乙酸预发酵,预发酵后的餐厨垃圾与酒糟混合进行甲烷发酵,并与不接任何菌种的对照组比较,考察2种预发酵方式对餐厨垃圾酸化抑菌及其与酒糟混合甲烷发酵的影响。研究结果表明,乙酸和乙醇预发酵对餐厨垃圾均具有良好的酸化抑菌效果,其大肠杆菌和金黄葡萄球菌数均比对照组降低了2个数量级以上;累积甲烷产量由高到低的顺序是:乙醇预发酵对照乙酸预发酵组,前者累积产甲烷量比对照组和乙酸预发酵组分别提高21.3%和49.8%;乙醇预发酵组乙醇浓度最高,而乙酸和丙酸浓度均最低;相反,乙酸预发酵组挥发性脂肪酸浓度积累导致产甲烷菌活性较低,其产气效率最低。因此,乙醇预发酵是一种既能实现餐厨垃圾酸化抑菌,又能维持发酵系统的稳定性,提高其后续产甲烷效率的有效预发酵方式。     

低分子量有机酸对不同合成磷源的释磷效应

采用化学浸提方法,研究了5种低分子量有机酸(草酸、柠檬酸、酒石酸、苹果酸、乙酸)对不同合成磷源的释磷效应。结果表明:供试有机酸(低浓度乙酸除外)均能促进不同合成磷源(DCP、OCP、FA、Fe-P、A l-P)中磷素的释放;其释磷效果与有机酸的种类和浓度有关,强弱顺序依次为柠檬酸、草酸、酒石酸、苹果酸、乙酸,有机酸浓度越高其释磷效果越好;有机酸与氟磷灰石(FA)反应后,溶液pH值升高。低浓度条件下pH值变化较大,而高浓度条件下pH值变化较小。     

Formation of furfurylthiol exhibiting a strong coffee aroma during oak barrel fermentation from furfural released by toasted staves

Furfurylthiol (FFT) is formed in white wines during alcoholic fermentation in the barrel from the furfural released by toasted staves. The quantity of furfural released into the must has a decisive effect on the quantity of FFT in the finished wine. Wines fermented in new barrels thus contain larger quantities of FFT than those fermented in used barrels. Fermentation conditions favorable to an excess production of H(2)S (hydrogen sulfide) by the yeast promote the formation of this volatile thiol. The presence of this volatile thiol in white wines is, therefore, closely related to the yeast's sulfur metabolism.     

Saccharomyces cerevisiae oxidative response evaluation by cyclic voltammetry and gas chromatography-mass spectrometry

This study is focused on the evaluation of the impact of Saccharomyces cerevisiae metabolism in the profile of compounds with antioxidant capacity in a synthetic wine during fermentation. A bioanalytical pipeline, which allows for biological systems fingerprinting and sample classification by combining electrochemical features with biochemical background, is proposed. To achieve this objective, alcoholic fermentations of a minimal medium supplemented with phenolic acids were evaluated daily during 11 days, for electrochemical profile, phenolic acids, and the volatile fermentation fraction, using cyclic voltametry, high-performance liquid chromatography-diode array detection, and headspace/solid-phase microextraction/gas chromatography-mass spectrometry (target and nontarget approaches), respectively. It was found that acetic acid, 2-phenylethanol, and isoamyl acetate are compounds with a significative contribution for samples metabolic variability, and the electrochemical features demonstrated redox-potential changes throughout the alcoholic fermentations, showing at the end a similar pattern to normal wines. Moreover, S. cerevisiae had the capacity of producing chlorogenic acid in the supplemented medium fermentation from simple precursors present in the minimal medium.     

pH、离子强度和介电常数对低分子量有机酸在红壤中吸附行为的影响

通过一次平衡法考察了pH、离子强度和溶剂介电常数对红壤吸附低分子量有机酸的影响。研究结果表明,随着溶液pH值的升高有机酸的吸附量降低,其中草酸和酒石酸的吸附量在pH 3.5 ~ 5.0范围内随着pH值的升高而急剧下降,之后缓慢下降（pH 5.0 ~ 7.0）。柠檬酸、酒石酸和苹果酸的吸附量在1 ~ 2 mmol/L初始浓度范围内随着离子强度的增加没有明显变化,但在2 ~ 20 mmol/L初始浓度范围内却随着离子强度的增加而增加。红壤对草酸、柠檬酸、酒石酸和苹果酸的吸附量均随着溶剂介电常数的减小而增加。当溶剂中含6% 的乙醇时,草酸、柠檬酸、酒石酸和苹果酸的吸附量分别是对照（不含乙醇）的1.05、1.05、1.11和1.31倍。     

Delignified cellulosic material supported biocatalyst as freeze-dried product in alcoholic fermentation

Freeze-dried delignified cellulosic (DC) material supported biocatalyst is proposed as a suitable form of biocatalyst to be preserved. The alcoholic fermentation of glucose using freeze-dried immobilized cells is reported. Freeze-dried immobilized baker's yeast cells on DC material do not need any protective medium during freeze-drying. The effect of initial glucose concentration and temperature on the alcoholic fermentation kinetic parameters is reported in the present study. It was found that the freeze-dried immobilized cells ferment more quickly than free freeze-dried cells and have a lower fermentation rate as compared with wet immobilized cells. However, repeated batch fermentations showed freeze-dried immobilized cells to ferment at about the same fermentation rate as wet immobilized cells. The results indicate that the freeze-dried immobilized cells must be further studied to establish a process for the preservation of immobilized cells.     

Behavior of a fenhexamid photoproduct during the alcoholic fermentation of Saccharomyces cerevisiae

The fungicide fenhexamid [N-(2,3-dichloro-4-hydroxyphenyl)-1-methylcyclohexanecarboxamide] degraded rapidly by UV or sunlight irradiation, yielding 7-chloro-6-hydroxy-2-(1-methylcyclohexyl)-1,3-benzoxazole (CHB) as a main photoproduct. CHB was isolated, and its effect on alcoholic fermentation of Saccharomyces cerevisiae was studied. The results indicate that the presence of CHB does not affect the extent of alcohol production. After 12 days, the amount of CHB in the fermentation medium decreased by ca. 65%. Only 25% of the missing CHB was recovered unchanged from yeasts, most likely because it was adsorbed on the yeast wall cell. The remaining part degraded during the fermentation process. Glucan and chitin, two potential adsorbents, which constitute yeast cell walls, exhibited affinity for CHB.     

自动化机械发酵食醋过程中品质变化规律

为全面了解转鼓式反应器固态发酵食醋过程中主要成分和风味物质的动态变化规律,该文对反应器发酵食醋过程进行跟踪取样,利用高效液相色谱、固相微萃取技术、气相色谱-质谱联用技术,对酒精、总酸、还原糖、氨基态氮、有机酸、挥发性风味物质含量变化进行实时监测,结合主成分分析方法,探究食醋不同发酵阶段的风味物质差异。结果表明,酒精含量在发酵0～4 d内迅速增加,随后逐渐下降至零;总酸含量呈现先快速上升后缓慢上升的趋势;还原糖含量呈先快速下降后逐渐上升,最后逐渐下降的趋势;氨基态氮呈现先快速上升后缓慢上升的趋势;乙酸和乳酸是主要的有机酸,整个发酵过程中,乙酸含量持续增加,乳酸含量呈先上升后下降趋势,其他有机酸含量较少,发酵期间变化波动相对较小;共检测出64种挥发性风味物质,包括酯类25种,醇类12种,酸类6种,酚类5种,醛类5种,酮类6种,杂环类5种;发酵前、中、后期的重要挥发性物质分别是醇类化合物、酯类和醛类化合物、酸类化合物。该结果为推进转鼓式固态发酵食醋反应器的实际生产应用提供了理论基础和数据参考。     

有机酸对针铁矿和膨润土吸附Cd2+、Pb2+的影响

用平衡吸附法研究了不同浓度的有机酸（乙酸、酒石酸和柠檬酸）对针铁矿和膨润土吸附Cd^2＋、Pb^2＋的影响。结果表明：（1）低浓度（〈0．6mmolL^-1）有机酸促进供试矿物吸附Cd^2＋和Pb^2＋，随着有机酸浓度增加，吸附逐渐被抑制。高浓度（〉1．0mmolL^-1）有机酸对Pb^2＋吸附的抑制作用比对Cd^2＋的强。有机酸浓度的变化对针铁矿Cd^2＋、Pb^2＋吸附率的影响大于对膨润土的。（2）不同Cd^2＋浓度下，有机酸对膨润土Cd^2＋吸附强度的影响大于针铁矿。加入高浓度Cd^2＋（8．0mmolL^-1）时，低浓度有机酸对膨润土吸附Cd^2＋的促进作用比加入低浓度Cd^2＋（0．4mmolL^-1）时明显，高浓度有机酸对膨润土吸附Cd^2＋的抑制作用与低浓度Cd^2＋时相近。（3）低浓度有机酸（〈0．6mmolL^-1）时，酒石酸、柠檬酸对针铁矿吸附Cd^2＋的促进作用大于乙酸，而它们对膨润土吸附Cd^2＋的促进作用相似；在三种有机酸高浓度（〉1．0mmol L^-1）时，针铁矿对Cd^2＋的吸附都趋于稳定，而柠檬酸对膨润土吸附Cd^2＋的抑制作用比乙酸和酒石酸的明显。不同种类有机酸下，矿物对Pb^2＋吸附率大小的变化基本一致。     

Combined impact of pH and organic acids on iron uptake by Caco-2 cells

Previous studies have shown that organic acids have an impact on both Fe(II) and Fe(III) uptake in Caco-2 cell. However, to what extent this effect is correlated with the anion of organic acids per se, or with the resulting decrease in pH, has not yet been clarified. Therefore, we studied the effect of five organic acids (tartaric, succinic, citric, oxalic, and propionic acid) on the absorption of Fe(II) and Fe(III) in Caco-2 cells and compared this with sample solutions without organic acids but set to equivalent pH by HCl. The results showed that the mechanisms behind the enhancing effect of organic acids differed for the two forms of iron. For ferric iron the organic acids promoted uptake both by chelation and by lowering the pH, whereas for ferrous iron the promoting effect was caused only by the lowered pH.     

低分子量有机酸对红壤磷酸单酯酶活性的影响

采用室内模拟试验研究了低分子量有机酸(柠檬酸、草酸、苹果酸、酒石酸)对红壤磷酸单酯酶活性的影响。结果表明,低浓度有机酸(<1μmol g-1)对磷酸单酯酶活性有促进作用,且促进作用大小依次为柠檬酸≈草酸>苹果酸>酒石酸;而高浓度有机酸(>5μmol g-1)则为抑制作用,且抑制作用大小依次为柠檬酸>草酸>苹果酸>酒石酸。当体系pH趋向酶促反应最佳pH时,磷酸单酯酶活性增强;反之,当体系pH远离酶促反应最佳pH时,磷酸单酯酶活性减弱。有机酸根一方面通过羧基的辅助作用提高磷酸单酯酶活性;另一方面通过释放土壤A l3+、Fe3+等金属离子,对土壤磷酸单酯酶活性有一定的抑制作用。