Hydrophilic and hydrophobic sorption of organic acids by variable charge soils: effect of chemical acidity and acidic functional group

Sorption of organic acids by variable-charge soil occurs through both hydrophilic and hydrophobic sorption. In this study, the effect of chemical acidity and the type of acidic functional group on the relative contribution of hydrophilic and hydrophobic processes to sorption by a gibbsite-dominated and a kaolinite-dominated variable-charge soils was quantified by measuring sorption isotherms from different electrolytes (CaCl2, Ca(H2PO4)2, and KCl). The A1 soil is dominated by gibbsite whereas the DRC soil is primarily kaolinite. The organic acids investigated include five chlorinated phenols (pentachlorophenol, 2,3,4,6-tetrachlorophenol, 2,4,6-trichlorophenol, 2,4,5-trichlorophenol, and 2,4-dichlorophenol) with pKa values ranging from 4.69 to 7.85 and two acidic herbicides (2,4-D (pKa = 2.8) and prosulfuron (pKa = 3.76)) that contain carboxyl and urea functional groups, respectively. Anion exchange of chlorinated phenols and prosulfuron on both variable-charge soils as well as 2,4-D sorption on the A1 soil was linearly correlated to chemical acidity. The effective positive surface charge [AEC/(AEC + CEC)] and the anionic fraction of the organic acid in solution, which are both pH-dependent, were sufficient to estimate the contribution of anion exchange to organic acid sorption except for 2,4-D sorption by DRC soil. The latter was much greater than would be predicted from the pKa of 2,4-D. Calcium bridging between silanol edge group and 2,4-D was hypothesized and corroborated by differences in sorption measured from KCl and CaCl2 solutions. For predicting contributions from hydrophobic processes, a log-log linear relationship between pH-dependent octanol-water (Kow(pH)) and organic carbon-normalized sorption coefficients (Koc(pH)) appeared adequate.     

Sorption of three tetracyclines by several soils: assessing the role of pH and cation exchange

Tetracyclines (TCs) are widely used in veterinary medicine for treatment and prevention of disease and are present in animal waste products. Detection of TCs in soil, sediments, and water, and the growing concern of their potentially adverse effect on natural ecosystems have resulted in a need to understand their behavior in aqueous soil systems. TCs have multiple ionizable functional groups such that at environmentally relevant pH values, they may exist as a cation (+ 0 0), zwitterion (+ - 0), or a net negatively charged ion (+ - -), which complicates predicting their sorption, availability, and transport. We investigated the sorption of oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC) by several soils varying in pH, clay amount and type, cation exchange capacity (CEC), anion exchange capacity (AEC), and soil organic carbon in 0.01 N CaCl2, 0.001 N CaCl2, and 0.01 N KCI. All three TCs are highly sorbed, especially in acidic and high clay soils. When normalized to CEC, sorption tends to decrease with increasing pH. A sorption model in which species-specific sorption coefficients normalized to pH-dependent CEC (Kd+00, kd+-0, and kd+--) and weighted by the pH-dependent fraction of each species fit the data well across all soils except for a soil rich in gibbsite and high in AEC. Resulting kd+00 values were more than an order of magnitude larger than values for either kd+0 and kd+--values such that kd+00 alone described most of the sorption observed as a function of pH for eight soils that varied in their mineralogy and pH (pH ranged from 4 to 8).     

Geochemical modulation of pesticide sorption on smectite clay

Pesticide adsorption by soil clays can be dramatically influenced by the exchangeable cations present. Among the common exchangeable base cations in soils (Ca2+, Mg2+, K+, and Na+), K+-saturated clays frequently demonstrate the strongest affinity for pesticides. In the presence of multiple exchangeable cations in the system, we hypothesize that the magnitude of pesticide sorption to soil minerals is proportional to the fraction of clay interlayers saturated with K+ ions. To test this hypothesis, we measured sorption of three pesticides with different polarities (dichlobenil, monuron, and biphenyl) by homoionic K- and Ca-smectite (SWy-2) in KCl/CaCl2 aqueous solutions. The presence of different amounts of KCl and CaCl2 resulted in varying populations of K+ and Ca2+ on the clay exchange sites. The sorption of dichlobenil and, to a lesser extent monuron, increased with the fraction of K+ on clay mineral exchange sites. Ca- and K-SWy-2 displayed the same sorption capacities for nonpolar biphenyl. X-ray diffraction patterns indicated that at lower fractions of K+-saturation, exchangeable K+ ions were randomly distributed in clay interlayers and did not enhance pesticide sorption. At higher populations of K+ (vs Ca2+), demixing occurred causing some clay interlayers, regions, or tactoids to become fully saturated by K+, manifesting greatly enhanced pesticide sorption. The forward and reverse cation exchange reactions influenced not only K+ and Ca2+ populations on clays but also the nanostructures of clay quasicrystals in aqueous solution which plays an important, if not dominant, role in controlling the extent of pesticide sorption. Modulating the cation type and composition on clay mineral surfaces through cation exchange processes provides an environmental-safe protocol to manipulate the mobility and availability of polar pesticides, which could have applications for pesticide formulation and in environmental remediation.     

2,4-D sorption in iron oxide-rich soils: role of soil phosphate and exchangeable Al

This study examined herbicide retention in iron oxide-rich variable charge soils (Ultisols) under no cultivation (forest), agriculture (farm), and turf maintenance (golf course) to explore the following hypothesis: inorganic phosphate accumulation from soil fertilization and liming to decrease exchangeable aluminum (Al) content will influence carboxylic acid herbicide sorption onto soils and leaching into groundwater. A suite of soil properties, including mineralogy (particularly soil iron and aluminum oxide content), exchangeable Al content, and soil phosphate content, influenced sorption of the anionic, 2,4-D. In general, 2,4-D sorption was lower in the presence of phosphate, possibly due to competition between phosphate and 2,4-D for surface sites or increase in surface negative charge resulting from phosphate sorption. Additionally, 2,4-D sorption was greater in the presence of exchangeable Al. It appears that 2,4-D may form surface complexes with or be electrostatically attracted to exchangeable aluminum in the soil. Our results suggest that carboxylic acid herbicides may be more easily leached in intensively managed Ultisols subject to continued phosphate fertilization and liming.     

Ionic strength-induced formation of smectite quasicrystals enhances nitroaromatic compound sorption

Sorption of organic contaminants by soils is a determinant controlling their transport and fate in the environment. The influence of ionic strength on nitroaromatic compound sorption by K+- and Ca2+ -saturated smectite was examined. Sorption of 1,3-dinitrobenzene by K-smectite increased as KCl ionic strength increased from 0.01 to 0.30 M. In contrast, sorption by Ca-smectite at CaCl2 ionic strengths of 0.015 and 0.15 M remained essentially the same. The "salting-out" effect on the decrease of 1,3-dinitrobenzene aqueous solubility within this ionic strength range was <1.5% relative to the solubility in pure water. This decrease of solubility is insufficient to account for the observed increase of sorption by K-smectite with increasing KCl ionic strength. X-ray diffraction patterns and light absorbance of K-clay suspensions indicated the aggregation of clay particles and the formation of quasicrystal structures as KCI ionic strength increased. Sorption enhancement is attributed to the formation of better-ordered K-clay quasicrystals with reduced interlayer distances rather than to the salting-out effect. Dehydration of 1,3-dinitrobenzene is apparently a significant driving force for sorption, and we show for the first time that sorption of small, planar, neutral organic molecules, namely, 1,3-dinitrobenzene, causes previously expanded clay interlayers to dehydrate and collapse in aqueous suspension.     

Influence of smectite hydration and swelling on atrazine sorption behavior

Smectites, clay minerals commonly found in soils and sediments, vary widely in their ability to adsorb organic chemicals. Recent research has demonstrated the importance of surface charge density and properties of exchangeable cations in controlling the affinity of smectites for organic molecules. In this study, we induced hysteresis in the crystalline swelling of smectites to test the hypothesis that the extent of crystalline swelling (or interlayer hydration status) has a large influence on the ability of smectites to adsorb atrazine from aqueous systems. Air-dried K-saturated Panther Creek (PC) smectite swelled less (d(001) = 1.38 nm) than never-dried K-PC (d(001) = 1.7 nm) when rehydrated in 20 mM KCl. Correspondingly, the air-dried-rehydrated K-PC had an order of magnitude greater affinity for atrazine relative to the never-dried K-PC. Both air-dried-rehydrated and never-dried Ca-PC expanded to approximately 2.0 nm in 10 mM CaCl2 and both samples had similar affinities for atrazine that were slightly lower than that of never-dried K-PC. The importance of interlayer hydration status in controlling sorption affinity was confirmed by molecular modeling, which revealed much greater interaction between interlayer water molecules and atrazine in a three-layer hydrate relative to a one-layer hydrate. The entropy change on moving atrazine from a fully hydrated state in the bulk solution to a partially hydrated state in the smectite interlayers is believed to be a major factor influencing sorption affinity. In an application test, choice of background solution (20 mM KCl versus 10 mM CaCl2) and air-drying treatments significantly affected atrazine sorption affinities for three-smectitic soils; however, the trends were not consistent with those observed for the reference smectite. Further, extending the initial rehydration time from 24 to 240 h (prior to adding atrazine) significantly decreased the soil's sorption affinity for atrazine. We conclude that interlayer hydration status has a large influence on the affinity of smectites for atrazine and that air-drying treatments have the potential to modify the sorption affinity of smectitic soils for organic molecules such as atrazine.     

面包预混合粉中酵母活力稳定性的研究

通过添加营养盐以及增加酵母用量稳定面包预混合粉中的酵母活力,借助F3流变发酵仪验证试验结果。正交实验结果表明:提高酵母活力影响因素的主次顺序为:NH4Cl,KH2PO4,MgSO4和CaSO4,营养盐的添加最优配比为:NH4Cl 0.04%,CaSO4 0.10%,MgSO4 0.08%,KH2PO4 0.09%能将面包比容提高8%左右,进行25℃密封储藏30 d后,面包预混合粉可做出的面包品质更为理想。     

无机盐对新型固定化酵母蔗汁酒精发酵的影响

以甘蔗作酒精酵母的固定化载体,以蔗汁为发酵培养基进行酒精发酵,通过电镜观察,酒精酵母不仅能吸附在甘蔗外表面,同时也能较好地吸附在甘蔗内部,比较固定化酵母与游离酵母数,发现固定化酵母数达到1011个/g,而游离细胞数只有107个/mL.通过考察不同浓度的CaCl2、MgSO4和KH2PO4对酵母酒精发酵性能的影响,发现1.0 g/L CaCl2和1.5 g/L KH2PO4可在最短时间内使二氧化碳生成速率达到最大值;而KH2PO4可明显地提高酒精发酵效率.     

Reaction-based model describing competitive sorption and transport of Cd, Zn, and Ni in an acidic soil

Predicting the mobility of heavy metals in soils requires models that accurately describe metal adsorption in the presence of competing cations. They should also be easily adjustable to specific soil materials and applicable in reactive transport codes. In this study, Cd adsorption to an acidic soil material was investigated over a wide concentration range (10(-8) to 10(-2) M CdCl2) in the presence of different background electrolytes (10(-4) to 10(-2) M CaCl2 or MgCl2 or 0.05 to 0.5 M NaCl). The adsorption experiments were conducted at pH values between 4.6 and 6.5 A reaction-based sorption model was developed using a combination of nonspecific cation exchange reactions and competitive sorption reactions to sites with high affinity for heavy metals. This combined cation exchange/specific sorption (CESS) model accurately described the entire Cd sorption data set. Coupled to a solute transport code, the model accurately predicted Cd breakthrough curves obtained in column transport experiments. The model was further extended to describe competitive sorption and transport of Cd, Zn, and Ni. At pH 4.6, both Zn and Ni exhibited similar sorption and transport behavior as observed for Cd. In all transport experiments conducted under acidic conditions, heavy metal adsorption was shown to be reversible and kinetic effects were negligible within time periods ranging from hours up to four weeks.     

酒精酵母的复合诱变与甜高梁秆汁培养基的优化

以甜高粱秆汁为基本原料,采用UV和DES复合诱变后获得酵母菌株FUD-3,再通过响应面法优化培养基中的营养因子CO(NH2)2、MgSO4、KH2PO4、CaCl2和FeCl3,提高了酒精的得率.结果表明:用驯化的方法使酒精酵母耐糖能力提高,通过UV与DES复合诱变的方式进行酵母的选育,以提高其产率.采取响应面法对发酵培养基进行优化,得到各因素的最佳质量浓度CO(NH2)2、MgSO4、KH2PO4、CaCl2和FeCl3的添加量分别为4.8318g/L、1.3734g/L、4.8114g/L、5.8571g/L0.6962g/L.训育后的酵母F-1与经过复合诱变优化后的酵母FUD-3发酵相比:残糖由26.41g/L减到9.24g/L、酒精产率由80.28%提高为93.46%,酒精的产量79.29g/L增加为100.44g/L,提高了26.67%.     

表面展示南极假丝酵母脂肪酶B的毕赤酵母FM22发酵培养基响应面优化

FM22培养基以中富的氮源、较强的适应性等优势,适用于毕赤酵母发酵。为进一步对毕赤酵母发酵表达南极假丝酵母脂肪酶B进行优化,选取培养基中对其影响较大的CaSO4、KH2PO4、（NH4）2SO4、PTM4为自变量,酶活力为响应值。通过单因素试验得自变量最佳值及高低水平,再采用Box—Behnken组合设计方法,模拟二次多项式同州方程的预测模型,研究各自变鼍及其交瓦作用埘酶活力的影响。最终得到自变最最佳值：KH2P0445．02g／L、（NH4）2s045．63g／L、CaS040．46g／L、PTM41．63mL／L,酶活力为3214．7U／gDCW,较优化前提高约40％。     

响应面法优化粗壮脉纹孢菌降解啤酒糟粗纤维的培养基

采用响应曲面法对粗壮脉纹孢菌降解啤酒糟粗纤维的培养基进行优化。通过Plackett-Burman 设计法及响应面分析法,评价不同比例CaCl2、KH2PO4、豆渣、(NH4)2SO4、MgSO4、尿素等6 个因素对粗壮脉纹孢菌降解啤酒糟粗纤维的影响。研究表明,豆渣、(NH4)2SO4、KH2PO4、CaCl2、MgSO4 是粗壮脉纹孢菌降解啤酒糟粗纤维过程中的主要影响因素。得到优化培养基：豆渣为26.08%、(NH4)2SO4 为3.71%、KH2PO4 为1.53%、CaCl2为0.24%、MgSO4 为0.08%,在此条件下重复发酵3 次,结果与理论预测值相近。     

Environmental factors influencing sorption of heterocyclic aromatic compounds to soil

Heterocyclic organic compounds containing nitrogen, sulfur, or oxygen (NSOs) are an important class of groundwater contaminants related to the production and use of manufactured gas, heavy oils, and coal tar. Surprisingly little is known about the processes that control sorption and transport of NSOs in the subsurface. In this study, the effects of various environmental factors including temperature, ionic strength, and dissolved/sorbed ion composition on the sorption of NSOs have been investigated by means of a soil column chromatography approach. For the investigated compounds, increased temperature normally decreases their sorption to soil. The enthalpy change of the sorption process corroborates earlier findings that van der Waals forces dominate the sorption of S- and O-heterocyclic compounds such as thiophene, benzothiophene, benzofuran, and 2-methylbenzofuran. Ionic strength and ion composition (Ca2+ vs K+ at given ionic strength) of the aqueous phase show no significant effects on the sorption of these compounds. Previous studies demonstrated that for N-heterocyclic compounds, cation exchange and surface complex formation rather than partitioning into soil organic matter control their overall sorption. In contrast to S- and O-heterocyclic compounds, increasing ionic strength reduced the sorption of ionizable N-heterocyclic compounds (pyridine, 2-methylpyridine, quinoline, 2-methylquinoline, and isoquinoline), due to increased electrostatic competition by cations. At given ionic strength, an increase of the K+/Ca2+ ratio in the mobile phase enhanced the sorption of N-heterocyclic compounds, consistent with cation exchange of the protonated organic species as the dominating sorption process. Among the investigated N-heterocyclic compounds sorption of benzotriazole showed a peculiar feature in that ternary surface complexation with Ca2+ appears to be the dominant sorption mechanism.     

Enhanced sorption of trichloroethene by smectite clay exchanged with Cs+

Trichloroethene (TCE) is one of the most common pollutants in groundwater, and Cs+ can be a cocontaminant at nuclear facilities. Smectite clays have large surface areas, are common in soils, have high affinities for some organic contaminants, and hence can potentially influence the transport of organic pollutants entering soils and sediments. The exchangeable cations present near smectite clay surfaces can radically influence the sorption of organic pollutants by soil clays. This research was undertaken to determine the effect of Cs+, and other common interlayer cations, such as K+ and Ca2+, on the sorption of TCE by a reference smectite clay saponite. Cs-saturated clay sorbed the most TCE, up to 3500 mg/kg, while Ca-saturated smectite sorbed the least. We hypothesize that the stronger sorption of TCE by the Cs-smectite can be attributed to the lower hydration energy and hence smaller hydrated radius of Cs+, which expands the lateral clay surface domains available for sorption. Also, Cs-smectite interlayers are only one or two water layers thick, which may drive capillary condensation of TCE. Our results implicate enhanced retention of TCE in aquifer materials containing smectites accompanied by Cs+ cocontamination.     

苹果汁中耐热菌培养基的优化及生长曲线

通过对苹果汁中分离耐热菌和德国标准耐热菌菌株基础培养基的正交优化,确定最佳的培养基。得出最佳培养基配比是(质量分数):德国标准菌:蛋白胨0.5%,果糖0.2%,酵母粉0.2%,MgSO4·2H2O0.1%,CaCl20.5%,KH2PO40.12%,MnSO4·4H2O0.05%;分离菌:蛋白胨0.5%,葡萄糖0.2%,酵母粉0.2%,MgSO4·2H2O0.1%,CaCl20.5%,KH2PO40.12%,MnSO4·4H2O0.05%。并计算得出吸光度与细菌浓度之间的关系公式及用优化培养基培养绘制耐热菌生长曲线。     

Mechanisms of attenuation of metal availability in in situ remediation treatments

One suite of in situ technologies for remediating metal contaminated soils involves the addition of reactive materials which lower metal availability. Until now it has been difficult to assess whether the amendment induced decrease in metal availability is due simply to increased sorption of the metal or whether it is the result of surface precipitation or other fixation mechanisms. This has made it difficult to predict the long-term stability of such remedial treatments. Using an isotopic dilution technique coupled with a stepwise acidification treatment, we examined changes in the labile pool of Cd and Zn in a polluted soil amended with either CaCO3, KH2PO4, red mud, or a kaolin byproduct. Fixation of both Cd and Zn was greatest in the KH2PO4 treated soil. The mode of fixation in this treatment was also found to be resistant to soil acidification. The results allowed a clear distinction between three classes of attenuation mechanisms which are hypothesized to increase in their resilience to environmental change as follows: reversible sorption < irreversible "fixation" at constant pH < irreversible "fixation" across a range of pH.     

嗜热碱性果胶酶产生菌的筛选及产酶条件优化

从极端土壤中分离到1株高效产碱性果胶酶菌株RH214,经鉴定为Bacillus smithii。为了进一步提高其产果胶酶活性,对产酶的培养基成分进行了优化。首先采用单因素试验筛选出最佳碳源为可溶性淀粉,最佳氮源为蛋白胨,金属盐为KH2PO4。根据单因素结果确定可溶性淀粉浓度、蛋白胨浓度和KH2PO4浓度为主因素,利用Box-Behnken试验设计和响应面法分析确定各因素的最优水平,得出菌株RH214的最优产酶条件:可溶性淀粉的浓度为85.6 g/L、蛋白胨浓度11.8 g/L、KH2PO4浓度为3.8 g/L、酵母粉1 g/L、FeSO41g/L、KCl 0.5 g/L、起始pH9.0、装液量80 mL/250 mL、温度40℃、摇床转速150 r/min,培养时间为16 h。在此条件下,进行验证实验,获得产酶活性为(88±0.86)U/mL,比未优化前的20.50 U/mL提高了4.3倍。     

Chemical extractions affect the structure and phenanthrene sorption of soil humin

Humin is a major fraction of soil organic matter and strongly affects the sorption behavior and fate of organic contaminants in soils and sediments. This study evaluated four different extraction methods for soil humins in terms of their organic carbon structural changes and the consequent effects on phenanthrene sorption. Solid-state 13C NMR demonstrated that 0.1 M NaOH exhaustively extracted humin and humin extracted with 6 M HF/HCl at 60 degrees C had a relatively high amount of aliphatic components as compared with 1 M HF-extracted humin. The treatment of 6 M HF/HCl at 60 degrees C greatly reduced carbohydrate components (50-108 ppm) from humin samples, i.e., more than 50% reduction. In addition, the humin from this 6 M HF/HCl treatment contained relatively more amorphous poly(methylene) domains than the humins extracted by other methods. With the respect to phenanthrene sorption, the linearity of sorption isotherm (N) and sorption affinity (Koc) varied markedly among the humin samples extracted by different methods. The NaOH exhaustively extracted humin had the most nonlinear sorption isotherm and the HF-extracted humin had the lowest Koc. It is concluded that humin samples from different extraction procedures exhibited substantial differences in their organic carbon structure and sorption characteristics, even though they were from the same soil. Therefore, one needs to be cautious when comparing the structural and sorption features of soil humins, especially when they are extracted differently. The 6 M HCl/HF extraction at elevated temperature is not encouraged, due to the modifications of chemical structure and physical conformation of organic matter.     

Evidence for pi-pi electron donor-acceptor interactions between pi-donor aromatic compounds and pi-acceptor sites in soil organic matter through pH effects on sorption

Elucidation of molecular-level interactions controlling the sorption of organic compounds in soils is of major theoretical and practical interest. Sorption of pi-electron donor compounds, pentamethylbenzene (PMB), naphthalene (NAPH), and phenanthrene (PHEN), in a number of soils was found to increase with decreasing pH in the range of approximately pH 2.5-7. This behavior could not be attributed to pH-dependent alteration of the hydrophobic character of humic substances, pi-H-bonding, interaction with mineral surfaces, interaction with black carbons, solute coplanarity, or pH effects on solute activity coefficient. No significant effect of pH was observed for non-pi-donor hydrophobic compounds, whether planar or not: trans-1,2-dichlorocyclohexane (DCCH), hexachloro-1,3-butadiene (HCBD), 1,2,4-trichlorobenzene (TCB), 2,2',5,5'-tetrachlorobiphenyl, and 3,3',4,4'-tetrachlorobiphenyl. The opposite pH effect was observed for 2-nonanol and 2-nonanone, which are non-pi-donors, but capable of H-bonding. Also, no pH-dependent sorption was observed between the pi-donor PHEN and alumina, a model inorganic surface. We propose that the pi-donor solutes interact with pi-acceptor sites in soil organic matter (SOM), including aromatic rings with multiple carboxyl groups, aromatic amines, or heteroaromatic amines. The pi-acceptor ability of such aromatic moieties would increase with protonation. pi-pi Interactions between PMB, NAPH, and PHEN, and model SOM acceptors, 1,3,5-benzenetricarboxylic acid (BTA), 1,4,5,8-naphthalenetetracarboxylic acid (NTA), and pyridine (PY) in methanol and methanol-water, were verified by the appearance of pH-dependent upfield 1H NMR chemical shifts induced by ring current effects. UV/vis spectra showed pH-dependent charge-transfer bands for various donors with NTA. No NMR shifts or charge-transfer bands were found for nondonor compounds paired with the model acceptors.     

Application of statistical experimental design to optimize culture requirements of Aspergillus sp. Zh-26 producing xylanase for degradation of arabinoxylans in mashing

The objective of this study was to isolate and characterize a strain of Aspergillus capable of producing xylanase. According to the morphology and comparison of ITS (Internal Transcribed Spacer) rDNA gene sequence, the strain Aspergillus sp. ZH-26 was identified as a strain of Aspergillus awamori. Statistically based experimental designs were applied for the optimization of xylanase production from A. awamori ZH-26. The considered medium components included 17 components as follows: yeast extract, tryptone, urea, NH(4)Cl, (NH(4))(2)SO(4), NaNO(3), KH(2)PO(4), K(2)HPO(4), NH(4)NO(3), MgSO(4), CaCl(2), CuSO(4), ZnCl(2), FeSO(4), MnSO(4), vitamin B(1), and EDTA. Yeast extract, tryptone, (NH(4))(2)SO(4), KH(2)PO(4), and CaCl(2) were identified to have significant effects on xylanase production using the Plackett-Burman experimental design. These 5 major components were subsequently optimized using the Box-Behnken experimental design. By response surface methodology and canonical analysis, the optimal concentrations for higher production of xylanase were yeast extract 5.95 g/L, tryptone 6.79 g/L, (NH(4))(2)SO(4) 13.37 g/L, KH(2)PO(4) 1.14 g/L, CaCl(2) 0.81 g/L. Under optimal conditions, the xylanase activity from A. awamori ZH-26 reached 47.3 U/mL. A small-scale mashing was carried out to evaluate the performance of the xylanase on degradation of arabinoxylans in mashing. Results showed that polymeric arabinoxylan content and wort viscosity in mashing with grist containing wheat malt sharply decreased to the basal level (from 470 to 185 mg/L) with the addition of xylanase.