顶青霉木聚糖酶的水解动力学与水解模式

从顶青霉（Penicillium corylophilum）培养液中分离纯化得到的3种木聚糖酶组分(Part A,Part B和Part C),对其水解动力学和水解模式的研究结果表明,3种木聚糖酶的动力学常数（桦木木聚糖为底物）分别为Part A,K     

肖尔布拉克高温大曲中细菌分离及产香研究

从肖尔布拉克酒业酱香型高温大曲中通过常温法和热处理法分离出了39株细菌,采用麸皮浸出汁培养基发酵,发现其中15株细菌的发酵液酱香味明显。将这15株细菌进行复发酵并进行蛋白酶活力的测定,显示15株菌株均有蛋白酶活力,其中有6株活力较强,分别为C1-3,C4,C8,R12,R19和R20。对这6株菌株进行基因组测序,C1-3、C4、R19和R20为枯草芽孢杆菌,C8为甲基营养型芽孢杆菌,R12为考克氏菌。对该6株菌发酵液进行气相色谱质谱分析,结果显示,6株菌检测出的物质数分别为:8种、19种、24种、15种、8种和9种。其中C1-3和R19生成的四甲基吡嗪含量较高。     

微生物酸性木聚糖酶及其应用的研究进展

木聚糖酶来源广泛,微生物酸性木聚糖酶作为木聚糖酶的一种,目前人们对其研究较少。文中介绍了产酸性木聚糖酶微生物菌株的来源,包括天然菌株和基因工程菌株;讨论了不同来源菌株发酵产酸性木聚糖酶的影响因素;总结了酸性木聚糖酶的纯化方法及纯酶性质并研究酶的结构特征与其耐酸性的关系,综述了酸性木聚糖酶在实际生产中的应用现状。     

反相高效液相色谱法检测单烷基二苯醚的质量分数

应用反相高效液相色谱法检测辛烯和二苯醚烷基化产物中单取代辛烷基二苯醚(C8-ADPO)的质量分数。色谱柱为C8色谱柱(250 mm×4.6 mm);流动相为V(甲醇)∶V(二氯甲烷)=8∶2;检测波长242 nm。C8-ADPO质量浓度为10~1 000 mg/L时与其峰面积成线性关系,线性方程为Y=7 912.08X+94 627.00,线性相关系数R=0.999 1,RSD为0.96%,回收率为100.0%~105.0%。     

超高效液相色谱-四极杆静电场轨道阱高分辨质谱法测定米炒人参炮制前后皂苷成分及其裂解规律的研究

目的 建立超高效液相色谱-四极杆静电场轨道阱高分辨质谱法（ultra performance liquid chromatography-quadrupole-orbitrap-mass spectrometry, UPLC-Q-Orbitrap-MS）检测分析方法。方法 采用Supelco C18色谱柱,以乙腈-0.1%甲酸水溶液梯度洗脱,应用电喷雾离子源（ESI electro-spray ionization）,负离子全扫描模式采集一、二级质谱数据,扫描范围为150~2000 m/z。结合质谱数据库及相关文献信息,运用X Calibur2.2软件对米炒人参中皂苷类成分进行鉴定。以6种人参皂苷Re、Rg1、Rb1、Rc、Rb2、Rb3进行模拟炮制,确定皂苷类成分裂解产物,明确皂苷成分的裂解规律。结果 从人参中检测出14个成分,鉴定出13种人参皂苷成分;米炒人参中检测出23个成分,鉴定出20种人参皂苷成分。通过比较人参米炒前后的皂苷类成分,发现米炒人参中存在人参中未检测到的8种稀有人参皂苷20(S)-Rg2、20(S)-Rh1、20(R)-Rh1、F2、20(S)-Rg3、20(R)-Rg3、20(S)-Rs3、20(R)-Rs3。模拟炮制结果表明,人参皂苷Re脱去C-20糖基,转化为稀有人参皂苷20(S)-Rg2;人参皂苷Rg1脱去C-20位糖基,转化为稀有人参皂苷20(S)-Rh1、20(R)-Rh1;人参皂苷Rb1、Rb2、Rb3、Rc脱去C-20或C-3位糖基,转化为稀有人参皂苷20(S)-Rg3、20(R)-Rg3或F2。结论 人参经米炒后,稀有人参皂苷成分增加,产生的稀有皂苷为原型皂苷发生苷键裂解而获得,模拟炮制可作为其裂解规律研究的有效方法。     

ID-MSPD-UHPLC-MS/MS检测烘焙食品及原料中的8种酚类污染物

建立了同位素稀释(isotope dilution,ID),基质分散固相萃取(dispersive solid phase extraction,DSPE)结合液相色谱串联质谱(UHPLC-MS/MS)检测烘焙食品及原料(面粉、面粉改良剂、蛋黄馅等)中双酚类污染物(双酚A、双酚B、双酚C、双酚F、双酚S、双酚AF)、紫外吸收剂UV-0和抗氧化剂TH1790的方法。样品经乙腈提取,C18分散吸附剂净化(蛋黄馅料等油脂含量高的样品先用正己烷出去油脂)后,采用C18色谱柱、乙腈-氨水为流动相梯度洗脱分离,以负离子(ESI-)多方应监测模式(schedule MRM)进行检测,内标法定量。8种酚类污染物在1.0～200.0μg/L范围内线性良好,相关系数(R2)在0.999以上。仪器检出限(LODs)0.5～5.0μg/L,加标回收率82.10%～113.20%,相对标准偏差为2.70%～9.50%。方法前处理简单,选择性强,灵敏度高,可满足烘焙食品及其原料中8种酚类污染物的检测。     

几种酶制剂对肉鸭稻谷离体消化能的影响

模拟肉鸭胃肠道内环境,采用两步离体消化法,分别研究了三种酶制剂(β-葡聚糖酶、纤维素酶和木聚糖酶)的6个水平(0、100、300、500、700、900μg/g)对稻谷离体消化能值的影响.结果表明:β-葡聚糖酶(x1)、纤维素酶(x2)、木聚糖酶(x3)的添加水平显著提高了稻谷离体消化能值(Y)(P<0.05),其二次回归关系分别为Y=-1E-06 x12+0.001 2 x1+6.695 9(R2=0.863 8,n=6,P<0.05),Y=-1E-06 x22+0.0018 x2+6.750 2(R2=0.866 8,n=6,P<0.05),Y=-1E-06x32+0.001 6x3+6.663 4(R2=0.954 8,n=6,P<0.05),从而确定出在试验条件下,β-葡聚糖酶、纤维素酶和木聚糖酶的最适添加量分别为600、900和800 μg/g.     

Bacillus subtilis木聚糖酶的纯化及其对小麦麸皮的作用

采用活性聚丙烯酰胺凝胶电泳和均质提取法相结合,从枯草芽孢杆菌(Bacillus subtilis)固体培养基发酵产物中分离得到了两种木聚糖酶. 薄层色谱和高压液相色谱分析结果进一步表明它们具有内切木聚糖酶的活力,分别定义为xyl Ⅰ和 xyl Ⅱ.两种酶具有相同的最适反应温度(50℃)和最适pH值(7.0).另外,还研究了内切木聚糖酶 xyl Ⅱ对小麦麸皮不溶性膳食纤维的作用.纸色谱分析结果表明,酶解产物中含有阿魏酰低聚糖.     

HPLC法测定草莓、蓝莓和黑莓中维生素C的含量

采用高效液相色谱法(HPLC)测定草莓、蓝莓和黑莓三种水果中的维生素C(VC)含量。色谱条件为0.1%的草酸溶液为流动相,Hypersil-C18色谱柱,检测波长为246 nm,流速为1.0 m L/min,柱温25℃。结果表明:维生素C在质量浓度为0~100 mg/L范围内有良好线性关系,线性回归方程为Y=10 765X-14 442,R2=0.996 8。高效液相色谱测得每百克草莓、蓝莓和黑莓中维生素C含量分别为68.84,19.44和34.10 mg。草莓、蓝莓、黑莓样品的回收率在95.53%~108.90%,94.00%~104.44%和95.32%~104.10%之间,高效液相色谱方法准确可靠,可用于其它水果维生素C含量的分析测定。     

液相色谱法测定固体饮料中维生素B12的含量

建立一种高效液相色谱(high performance liquid chromatography,HPLC)测定固体饮料中维生素B12含量的方法。样品经水超声、提取、离心、免疫亲和柱净化处理,采用C18色谱柱,以磷酸氢二钠溶液:甲醇=76∶24(体积比)作为流动相,361 nm紫外检测,外标法测定。结果表明,维生素B12在0.1μg/m L~10μg/m L浓度线性范围内关系良好,相关系数(R2)大于0.999,加标样品的平均回收率为91.4%,相对标准偏差(relative standard deviation,RSD)为(n=9)2.55%,检出限为0.001μg/g。试验表明,该方法灵敏度和准确性较高,具有较好的可操作性,适用于固体饮料中维生素B12含量的测定。     

Ferulic Acid Production in the Brewing of Rice Wine (Sake)

The traditional Japanese alcoholic beverage sake is produced by fermentation of rice by Saccharomyces cerevisiae and Aspergillus oryzae. A. oryzae releases ferulic acid, an antioxidant, from steamed rice during the fermentation process. The concentration of ferulic acid increased with time during fermentation and the production rate peaked 9–12 days post inoculation. Analysis of the fermentation cultures of Aspergillus oryzae, by high‐performance liquid chromatography (HPLC), revealed that p‐coumaric acid induced an 18.9‐fold increase in the level of ferulic acid. Furthermore, SDS‐PAGE analysis revealed an increase or decrease in the level of specific proteins after the addition of p‐coumaric acid to fermentation cultures of Aspergillus oryzae. Ferulate esterase (FAE) activity was observed in the fermented sake ten days following the start of the fermentation process. These results suggest that the level of ferulic acid is regulated by the enzymes synthesized by A. oryzae during the sake brewing process.     

PRODUCTION AND CHARACTERISTICS OF RED RICE SAKE

Red rice sake was efficiently produced from unpolished red rice without cooking by use of rice koji prepared with shochu koji mold, Aspergillus kawachii, as saccharifying agent. A comparative study was made of red rice sake made with rice koji and red rice wine made with a preparation of glucoamylase known as Sumizyme. Red rice sake contained about 13% ethanol and its acidity was 8.6. Large amounts of volatile compounds, such as isobutyl alcohol and ethyl acetate, were found in the red rice sake. The red color of the red rice sake was more intense than that of the red rice wine. The quality of red rice sake was better than that of red rice wine, as assessed by gas chromatography, spectrophotometric analysis and organoleptic testing. In accordance with the traditional method for sake brewing, red rice, rice koji and tap water were added to the initial mash. The red color of the red rice sake made with these additions was more intense than that of red rice sake made without these additions. The rice wine was somewhat improved by these additions, as assessed by organoleptic testing. The body of the resultant rice wine was fortified with dextrin and its mild characteristics were derived from sugar and dextrin.     

宇佐美曲霉木聚糖酶的纯化及其性质

宇佐美曲霉E001固态发酵成熟曲经水浸提、硫酸铵盐析、Phenyl-SepharoseCL-4B疏水层析、SephadexG-75凝胶过滤层析、DEAESepharosefastflow阴离子交换层析等提纯步骤,获得了比酶活3047IU/mg蛋白的纯木聚糖酶,其SDS-PAGE呈单一条带。用SDS-PAGE和凝胶过滤测得木聚糖酶的相对分子质量分别为23.2kD和23.0kD,表明该酶蛋白为单亚基。纯木聚糖酶的最适作用温度和pH值分别为50℃和4.6;以燕麦木聚糖为底物的酶动力学常数Km和Vmax值分别为5.27mg/ml和6494μmol/(min·mg);Ca2+、EDTA对酶有激活作用,而Sn2+、Pb2+、Fe3+有强烈的抑制作用。     

QTL mapping of sake brewing characteristics of yeast

A haploid sake yeast strain derived from the commercial diploid sake yeast strain Kyokai no. 7 showed better characteristics for sake brewing compared to the haploid laboratory yeast strain X2180-1B, including higher production of ethanol and aromatic components. A hybrid of these two strains showed intermediate characteristics in most cases. After sporulation of the hybrid strain, we obtained 100 haploid segregants of the hybrid. Small-scale sake brewing tests of these segregants showed a smooth continuous distribution of the sake brewing characteristics, suggesting that these traits are determined by multiple quantitative trait loci (QTLs). To examine these sake brewing characteristics at the genomic level, we performed QTL analysis of sake brewing characteristics using 142 DNA markers that showed heterogeneity between the two parental strains. As a result, we identified 25 significant QTLs involved in the specification of sake brewing characteristics such as ethanol fermentation and the production of aromatic components.     

木聚糖酶合成菌株的诱变选育

以黑曲霉、蜡状芽孢杆菌和枯草芽孢杆菌为出发菌株,采用紫外物理诱变及紫外物理诱变和紫外亚硝酸复合诱变的方法,选育培养出产木聚糖酶酶活较高的菌株。经过紫外诱变后黑曲霉菌株所产酶酶活为17.3716U/ml;经过复合诱变后黑曲霉菌株所产酶酶活为15.2144U/ml。经过紫外诱变后枯草芽孢杆菌和蜡状芽孢杆菌菌株所产木聚糖酶酶活分别为16.1328U/ml和13.7200U/ml。     

RICE WINE BREWING WITH SPROUTING RICE,SPROUTING RICE INFECTED WITH ASPERGILLUS ORYZAE AND RICE KOJI

Fermentation tests were performed with sprouting rice, sprouting rice infected with koji mold, i.e. Aspergillus oryzae and rice koji, as saccharifying agent. Characteristics of the various rice wines were compared by gas chromatography and organoleptic testing. The rice wine made with sprouting rice was colorless and had light and refined characteristics in terms of both aroma and taste. The rice wine made with sprouting rice infected by Aspergillus oryzae was rich in isoamyl alcohol, isoamyl acetate and acetaldehyde; it was faintly yellow in color and had rich and mild characteristics. This rice wine had something in common with conventional Japanese sake as compared with the sprouting rice wine, and it might be a transitional intermediate between ancient sprouting rice wine and conventional Japanese sake. In accordance with the traditional method for sake brewing, starchy materials, tap water and sprouting rice as the saccharifying agent were added to the initital mash as first and second additions. The rice wine was somewhat improved by these additions, as assessed by organoleptic testing. The body of the resultant rice wine was fortified with dextrin and its acidic taste was masked by sugar and dextrin.     

米曲霉种内原生质体融合选育优良菌株

米曲霉HL和L5是来自酱油酿造企业的生产菌株。HL的生长速度快,而L5的中性蛋白酶活力高。以HL和L5为亲本,进行原生质体融合,筛选得到一株融合株R6。融合株比亲本株生长速度更快,孢子成熟时间快3h,中性蛋白酶活力分别比2株亲本菌株提高25.6%和19.9%,酱醅氨基氮值也比亲本菌株提高8%和5.6%。     

木聚糖酶产生菌的筛选、发酵及酶学性质

该研究对木论自然保护区土壤中高产木聚糖酶的菌株进行了分离,经菌落形态观察、ITS基因序列分析对菌株进行了鉴定,并通过单因素固态发酵实验确定最佳产酶条件。结果表明,筛选到1株高产木聚糖酶菌株,并鉴定为黑曲霉（Aspergillus niger）。其最佳产酶培养基配方：玉米芯与麸皮质量比为1∶7、氮源为硫酸铵（添加量1.4 g/L）、初始pH值为5.0、料水比为1∶3.5（g∶mL）,接种量为7.5%。在此优化条件下,木聚糖酶酶活最高可达10 801.3 IU/g。酶学性质研究表明,木聚糖酶的最适作用pH值为5.5、最适作用温度为37 ℃。     

Molecular breeding of the Mureka-non-forming sake koji mold from Aspergillus oryzae by the disruption of the mreA gene

Mureka-non-forming sake koji molds were constructed from an Aspergillus oryzae industrial strain by the disruption of the mreA gene using a host-vector system with the ptrA gene as a dominant selectable marker. All of the mreA gene disruptants obtained retained the advantages of the host strain in terms of the brewing characteristics, while their isoamyl alcohol oxidase (IAAOD) activities were significantly lower than that of the host strain. Sake brewing was successfully carried out using the koji prepared with the disruptants, followed by storage of the resultant non-pasteurized sake (nama-shu). The isovaleraldehyde (i-Val) concentration in the sake brewed the host strain increased rapidly and reached the threshold values for mureka, 1.8 ppm and 2.6 ppm after storage at 20 degrees C for 42 d and 63 d, respectively, while those of the disruptants were less than 0.5 ppm even after storage at 20 degrees C or 30 degrees C for 63 d. In the sensory evaluation of the sake stored at 20 degrees C or 30 degrees C for 63 d, all members of the panel recognized the strong mureka flavor of the sake brewed with the host strain, while they did not detect this flavor in the sake brewed with the disruptants. Thus, we concluded that the mreA gene disruptants can be used for the production of sake in which mureka is not formed.     

宇佐美曲霉产木聚糖酶的固态发酵条件研究

研究了培养基组分及培养条件对宇佐美曲霉(Asp usamii) 固态发酵产木聚糖酶的影响。采用Plack ett Burman和Box Behnken实验设计确定了最佳培养基组成和培养条件为:麸皮3 4g ,玉米芯4 6 g ,NH4NO31% ,KH2 PO40 3% ,CaCl2 0 1% ,MgSO40 1% ,Tween 80 0 4 % (均为相对于固体料的质量百分数) ,液固比为1 2∶1;最佳初始pH为自然pH ,2 8℃静置培养72h ,其间翻曲2～3次。酶活最高达到74 4 2IU/g(干曲)。