葡萄糖氧化酶的研究进展

葡萄糖氧化酶是一种需氧脱氢酶,对人体无毒、副作用,能利用氧将葡萄糖氧化成葡萄糖酸而有效除氧,因而广泛用于抗氧化剂、葡萄糖酸、尿糖试纸和生物传感器的生产。本文综述了葡萄糖氧化酶的研究进展。     

葡萄糖氧化酶的研究进展

葡萄糖氧化酶是一种需氧脱氢酶,对人体无毒、副作用,能利用氧将葡萄糖氧化成葡萄糖酸而有效除氧,因而广泛用于抗氧化剂、葡萄糖酸、尿糖试纸和生物传感器的生产.本文综述了葡萄糖氧化酶的研究进展.     

葡萄糖氧化酶的生产及应用

葡萄糖氧化酶能够利用氧气将葡萄糖氧化成葡萄糖酸而有效去除氧,因而被广泛用作抗氧化剂、葡萄糖酸、尿糖试纸和生物传感器的生产。综述了葡萄糖氧化酶作为生物去氧剂的作用机理、生产工艺条件以及在食品、医药等行业的广泛应用。     

葡萄糖氧化酶及其应用

葡萄糖氧化酶是需氧脱氢酶,易溶于水,不溶于有机溶剂。工业生产多从黑曲霉中提取,该酶主要与过氧化氢酶共同作用催化葡萄糖产生葡萄糖酸,同时消耗氧。葡萄糖氧化酶广泛应用于食品、医药、饲料等行业中,起到了去除葡萄糖、脱氧、杀菌等作用。     

微生物葡萄糖氧化酶的研究进展

葡萄糖氧化酶是一种能够专一性催化β-D-葡萄糖氧化生成葡萄糖酸和过氧化氢的需氧脱氢酶,在食品、医药、化工、纺织、生物技术等领域具有重大应用价值。微生物是产葡萄糖氧化酶的主要来源,具有生长繁殖快、产酶效率高、纯化过程简单、适合商业化生产等特点。该文从产葡萄糖氧化酶的微生物来源、产酶菌株的基因工程改造及葡萄糖氧化酶的应用等方面对微生物葡萄糖氧化酶进行综述,为产葡萄糖氧化酶微生物的开发及基因工程技术在菌种选育上的应用提供理论参考。     

葡萄糖氧化酶及其在食品工业中的应用

葡萄糖氧化酶是一种氧化还原酶,是在食品工业中有广泛用途的食品添加剂和加工助剂。在氧存在下,它可以将D-葡萄糖氧化成与D-葡萄糖-δ-内酯相对应的葡萄糖酸。因此,葡萄糖氧化酶既是一种氧化剂,又是一种能对葡萄糖起氧化作用的脫糖剂。目前葡萄糖氧化酶已被许多国家公认是一种可以安全使用的食品抗氧剂,可以代替多种化学抗氧剂广泛应用于各种食品和食品加工工艺中。     

葡萄糖氧化酶的性质及其在食品工业中的应用

葡萄糖氧化酶(Clucose Oxidase,全称β—D—吡喃型葡萄糖需氧脱氢酶,简称G OD)是食品工业和医疗诊断常用的一种酶,这种酶能高度专一性地催化β—D—葡萄糖与空气中的氧反应,使葡萄糖氧化为葡萄糖酸,所以葡萄糖氧化酶既是一种去氧剂,又是一种脱糖剂,其催化时需要F A D作为辅基参与作用,反应过程如下: 总反应式:C_6H_2O_6 1/2O_2→C_6H_(12)O_7 G OD广泛分布于动、植物和微生物体     

双酶法生产葡萄糖酸锌的新工艺

介绍一种双酶法生产葡萄糖酸锌的新工艺。新工艺采用葡萄糖作为主要原料,葡萄糖氧化酶在过氧化氢酶的协同作用下将葡萄糖氧化为葡萄糖酸,同时流加一定浓度的氧化锌悬液进行中和,最终生成葡萄糖酸锌。研究葡萄糖浓度、pH、温度、空气流量对葡萄糖酸锌合成工艺的影响,并对葡萄糖酸锌结晶的最适宜条件进行初步研究。通过本工艺生产的葡萄糖酸锌纯度可达99.6%,可用于食品、医药、饲料、化妆品等诸多领域。     

紫茉莉根水提物对葡萄糖及四氧嘧啶致高血糖小鼠的降血糖作用

通过腹腔注射给予葡萄糖、四氧嘧啶建立小鼠高血糖模型,灌胃给予10g.kg-1·bw-1紫茉莉根水提物,连续给药10d,葡萄糖氧化酶法测空腹血糖,研究了紫茉莉根水提物对葡萄糖、四氧嘧啶、葡萄糖+四氧嘧啶致高血糖小鼠空腹血糖的影响.结论表明按10g.kg-1.bw-1连续10d灌胃给予葡萄糖、四氧嘧啶、葡萄糖+四氧嘧啶诱导...     

葡萄糖氧化酶及其在酒中的应用

葡萄糖氧化酶在氧化葡萄糖的过程中消耗氧。酿酒工业利用葡萄糖氧化酶的这一特征广泛应用于啤酒的抗氧化和混浊。保持葡萄酒的稳定性、平衡性。还可以用来酿制低醇葡萄酒。     

微生物葡萄糖氧化酶的研究进展

葡萄糖氧化酶（EC 1.1.3.4）作为一种高特异性氧化还原酶,能够催化β-D-葡萄糖转化为葡萄糖酸,并产生过氧化氢（H2O2）,在医疗检测、食品、生物燃料电池、畜牧养殖等领域发挥着极其重要的作用。该文从微生物来源、克隆表达、发酵优化、分离纯化及应用方面,阐述了葡萄糖氧化酶的研究进展,以期为葡萄糖氧化酶的开发和应用提供参考。     

Optimising glucose conversion in the production of reduced alcohol wine using glucose oxidase

The use of a glucose oxidase (GOX)-catalase enzyme system for the production of reduced-alcohol white wine is investigated. The process reduces alcohol potential by converting glucose to gluconic acid. Trials were conducted with grape juice and model solution to determine key factors affecting the activity of the GOX system, and to optimise the process for use with grape juice. Under our processing conditions, the low pH of grape juice was found to be a dominant limiting factor in the rate and extent of glucose conversion by GOX. An optimised process for glucose conversion (up to 87%) was developed after investigation of the effects of enzyme dosage, sparging, aeration and mixing rates, and temperature. Maximum GOX activity was observed during the first 4 to 6 h of treatment, after which a significant decrease in the rate of gluconic acid formation and glucose degradation occurred. An expected increase in titratable acidity and concurrent decrease in pH during GOX treatment was also observed, and is attributable to an increase in the juice gluconic acid concentration of ca 73 g/l.     

Variation of Microwave Dielectric Properties in the Glucose Biosensor System

Glucose biosensor is generally based on the reaction between glucose and glucose oxidase, which produces gluconic acid and hydrogen peroxide. The gluconic acid is a conductive material, while hydrogen peroxide has polar molecules. This article examines the changes of dielectric properties due to the conductive loss below 2 GHz and dipole orientation of above that frequency of this reaction. The difference between the dielectric loss of glucose solution and the dielectric loss of glucose-enzyme reaction can be related to the glucose concentration in the samples, such as orange juice, black grape juice, sugarcane juice, and sapodilla juice. A good sensitivity to these differences due to the effect of ionic conductivity and dipole orientation was found at 1 and 16.44 GHz, respectively. The minimum detection limit of glucose concentration in the proposed technique was about 0.01 M (0.20 g/100 ml) with an optimum reaction ratio of about 1:1 between the enzyme solution and the glucose solution. This technique could benefit the future development of microwave biosensor by which both ionic conductivity and dipole effects can be considered simultaneously.     

Effects of pH and dissolved oxygen on cellulose production by Acetobacter xylinum BRC5 in agitated culture

Acetobacter xylinum BRC5 was cultivated in a jar fermentor using glucose as the sole carbon source. Strain BRC5 oxidized almost all of the glucose to gluconic acid; thereafter, it biosynthesized cellulose by utilizing gluconic acid accumulated in the broth. The optimal pH for metabolizing glucose to gluconic acid was 4.0, while a pH of 5.5 was preferred for cell growth and cellulose production from the accumulated gluconic acid in the medium. Shifting the pH from 4.0 to 5.5 during the cellulose production phase in batch cultures improved cellulose production and reduced the total fermentation time, compared to batch cultures at constant pH. In constant fed-batch culture, 10 g/l of cellulose was obtained from 40 g/l of glucose, a yield which was approximately 2-fold higher than in batch culture with the same initial glucose concentration, even without control of the level of dissolved oxygen. The highest cellulose yield was obtained in fed-batch cultures in which the dissolved oxygen concentration was controlled at 10% saturation. Control of pH and dissolved oxygen to optimal levels was effective for improving the production rate and yield of cellulose, to achieve a high cellulose productivity of 0.3 g cellulose/l x h. Approximately 15 g/l of cellulose was considered to be the highest yield obtainable using conventional fermentors because the culture broth then became too viscous to allow satisfactory aeration.     

Bleaching of colored whey and milk by a multiple-enzyme system

Carotenoids are broadly used to enhance the color of cheese types like Cheddar and Gouda. While ～80 % of the colorants are transferred into the cheese, the rest remains in the whey and impedes its commercial utilization. Therefore, cheese whey is currently bleached chemically by addition of either hydrogen peroxide or benzoyl peroxide in the industrial practice. To avoid heat- and peroxide-induced protein denaturation and the formation of off-flavors, an enzymatic bleaching process was developed. The ability of the fungal peroxidase MsP1 to degrade carotenoids was successfully employed for the bleaching of colored whey and milk in two- and three-enzyme systems, respectively. The systems were composed of MsP1, glucose oxidase, and when necessary, acid lactase. The initial step of the three-enzyme system was the lactase-catalyzed hydrolysis of lactose to galactose and glucose. The latter served as a substrate for the enzyme glucose oxidase in the second step which yielded gluconic acid and hydrogen peroxide. Finally, MsP1 oxidatively degraded the carotenoids. The activities of the involved enzymes were fine-tuned to optimize the bleaching process.     

Antibacterial Effect of Glucose Oxidase on Growth of Pseudomonas fragi as Related to pH

The effect of glucose oxidase (GOX) catalyzed reaction with glucose on Pseudomonas fragi was analyzed in nutrient broth and fish extract media. Growth of P. fiugi in nutrient broth was clearly suppressed by 1.0, 2.0 and 4.0 mg/mL glucose when combined with 0.5–2.0 U/mL GOX. The same GOX/glucose combinations inhibited P. frasi growth in fish extract media. Viable cell numbers in fish media showed clear growth inhibition with combinations of l.0–2.0 U/mL GOX and 8.0–16.0 mg/mL glucose. Higher GOX and glucose rapidly produced 2.0–2.5 unit decreases in pH, but produced enough gluconic acid to precipitate fish proteins. Use of 0.5 U/mL GOX in fish extract media resulted in slow, sustained activity with potential for inhibition of microbial growth in foods without excessive acidity.     

Production of gluconic acid from whey by free and immobilized Aspergillus niger

Deproteinized whey has been used as a fermentation medium for the production of gluconic acid by Aspergillus niger immobilized in polyurethane foam or free cells. Addition of a small amount of glucose (0.5%, w/v) in the whey medium enhanced the production of gluconic acid by 140% over the unsupplemented medium. Immobilized mycelia produced 92 g of gluconic acid from 1 L of whey medium containing 9.5% lactose and 0.5% glucose against 69 g by free mycelia. Immobilized mycelia can be reused.     

EFFECTS OF GLUCOSE OXIDASE, HEMICELLULASE AND ASCORBIC ACID ON DOUGH AND BREAD QUALITY

ABSTRACT

In this study, glucose oxidase alone or its combinations with hemicellulase or ascorbic acid were used in bread making. Glucose oxidase alone mainly decreased dough extensibility. It produced stiffer and less extensible dough. Combinations of glucose oxidase–hemicellulase presented lower extensibility and were more resistant to extension than glucose oxidase alone. When glucose oxidase–ascorbic acid combinations were used, the softening degree significantly decreased, regardless when added the lowest glucose oxidase in combination with ascorbic acid. Glucose oxidase–ascorbic acid combinations significantly modified dough resistance. The glucose oxidase alone significantly increased specific loaf volume. The Dallman value of loaves made with glucose oxidase alone was found higher than for control. The most dramatic effect of additives on specific loaf volume was observed when glucose oxidase–hemicellulase combinations were added. This effect has been ascribed to redistribution of water from the hemicellulose to gluten, which would render the gluten more extensible. Specific loaf volume showed a significant enhancement when glucose oxidase–ascorbic acid combinations were added, but this effect was not as good as glucose oxidase–hemicellulase. The effects of glucose oxidase and its combinations with ascorbic acid and hemicellulase on dough rheology and bread quality are highly dependent on the amount of enzyme and the original wheat flour quality.

PRACTICAL APPLICATION

In practice, appropriate combinations of glucose oxidase with hemicellulase can be used as improvers in bread making, depending on their combination levels. This study will show the way to new research about glucose oxidase, ascorbic acid and hemicellulose.

     

利用TAIL-PCR克隆Gluconobacter suboxydans葡萄糖脱氢酶基因及其生物信息学分析

以Gluconobacter suboxydans J菌株基因组DNA为模板,基于吡咯喹啉醌附着位点的保守区域设计引物,通过交错式热不对称PCR获得编码葡萄糖脱氢酶（glucose dehydrogenase,GDH）的全长基因（gdh）,并对其序列进行生物信息学分析。结果表明：gdh基因全长2 268 bp,编码755个氨基酸,其蛋白序列与Gluconobacter属的GDH具有较高的同源性。GDH的分子质量约为81.72 ku,pI值约为5.14;GDH蛋白的二级结构由18.41%的α-螺旋、16.16%的延伸和65.43%的无规则卷曲3种结构模块组成;GDH N末端的AA 1～140区域有5个跨膜结构域。     

Cysteine-loaded pH-responsive liposome/gold nanoparticles as a time-temperature indicator with instantaneous color change

A novel time-temperature indicator (TTI) with instantaneous color change was developed by applying cysteine-loaded pH-responsive liposome/gold nanoparticles (Cys-pRL/AuNP) as a pH indicator to the glucose oxidase/glucose (GOx/Glu) TTI. It was hypothesized that the pH change caused by gluconic acid production causes cysteine release from the Cys-pRL, resulting in the AuNP aggregation (red→blue) at the pRL critical pH. The Cys-pRL with a lipid bilayer (phosphatidylcholine/dioleoylphosphatidylethanolamine/cholesterol/oleic acid in molar ratio of 24/24/40/12) was prepared by the freeze-drying method. The spherical morphology of the Cys-pRL was confirmed from TEM micrographs. FTIR analysis revealed that the cysteine was captured in the Cys-pRL. The critical pH of the pRL was found to be 4.0–4.7 by using [Cys-pRL/AuNP]/HCl. [Cys-pRL/AuNP]/[GOx/Glu] TTI showed the instantaneous color change in a narrow transition zone (pH 4.0–4.6), whereas a conventional TTI with regular pH indicator bromocresol green/[GOx/Glu] showed the gradual color change in a wide transition zone (pH 3.9–6.1).