固态发酵生产高活力纤维二糖酶

在固态发酵条件下,对７个纤维二糖酶生产菌株进行了筛选,发现ＡｓｐｅｒｇｉｌｕｓｎｉｇｅｒＬＯＲＲＥ０１２为纤维二糖酶高产菌株。研究了培养时间、温度、培养基含水量及初始ｐＨ等因子对该菌形成纤维二糖酶的影响。当培养基采用自然ｐＨ（约６．０）、含水量７０％,接种后在３０℃下先培养２ｄ,再在２５℃下培养２ｄ,每克干酶曲所含的纤维二糖酶活力可达到４３０．５６ＩＵ。由此获得的纤维二糖酶曲与Ｔｒｉｃｈｏｄｅｒｍａｒｅｓｅｉ产生的纤维素酶曲在糖化纸浆过程中有明显的协同作用,当两者以１∶１０混合使用时（纤维二糖酶与滤纸酶活力之比约为０．４４）,可有效地消除水解产物中纤维二糖的累积,使纤维纸浆的酶水解得率高达９０．７％。     

Studies on the Two Forms of Amyloglucosidase of Aspergillus niger van Tieghem

Two isoenzymes of amyloglucosidase, designated as AG-I and AG-II, elaborated exocellularly by a strain of Aspergillus niger van Tieghem, were separated and purified to homogeneity. The enzymes, produced in a selective medium, were separated and purified on a column of DEAE-Sephadex A-50. The molecular weights of AG-I and AG-II were found to be 69, 810 and 89,130 respectively. The two enzymes were glycoproteins and differed in their carbohydrate contents, pH and temperature stabilities and optima for activity. Their activation energies and Km values also varied. AG-II, had a higher molecular weight, carbohydrate content, increased acid tolerance and was synthesized earlier to AG-I (when the pH of the medium was acidic). Hg and Ag salts caused partial inhibition of their activities.     

Studies on the Thermophilic Amylolytic Enzymes of a Strain of Aspergillus niger

A laboratory isolate of Aspergillus niger elaborated considerable quantities of exocellular amylolytic enzymes. The enzymes exhibited a highly thermophilic nature. The culture filtrate exhibited two pH optima for dextrinogenic and one for saccharifying activity. Electrophoretic studies of the culture filtrate revealed three major proteins, two exhibiting α-amylase and one amyloglucosidase activity.     

产聚半乳糖醛酸酶的黑曲霉诱变育种

利用透明圈法对黑曲霉SH312菌株进行初筛,得到黑曲霉SH312-26菌株。对其进行紫外线诱变,筛选出SH312-26-19菌株,该菌株聚半乳糖醛酸酶酶活力为113.68kU/mL,较出发菌株SH-312-26提高了1.44倍;果胶酯酶酶活力为14.34kU/mL,较出发菌株提高了0.14倍,其幅度远小于聚半乳糖醛酸酶酶活的提高幅度。突变株SH312-26-19经斜面传代培养了5代,产酶遗传特性稳定。     

黑曲霉Z-25产葡萄糖氧化酶胞外酶发酵培养基优化研究

以黑曲霉Z-25(Aspergillus niger Z-25)作为葡萄糖氧化酶胞外酶生产菌株,研究提高胞外酶活力的环境因素.通过单因素试验,确定了主要影响葡萄精氧化酶合成的四个因素,采用四因素三水平L9(34)正交试验,确定了产葡萄糖氧化酶胞外酶的优化发酵条件:葡萄糖添加量为10%、(NH4)2SO4添加量为0.5%、月示蛋白胨添加量为1.5%、吐温80添加量为3%.在优化条件下,葡萄糖氧化酶的活力是优化前的242%.     

高糖化酶活菌株的选育及其在山西老陈醋酿造中的应用

采用N~+注入、氯化锂-紫外线复合诱变方法对糖化酶生产菌株黑曲霉As3.4309反复进行诱变处理,获得了1株高糖化酶活的突变株IV5-66,其糖化酶活力为出发菌株的3.5倍,该菌株具有无霉腐味、不产生色素等特点,具有较高的应用价值。建立了利用该突变株制备高糖化酶活麸曲的工艺,并将高糖化酶活麸曲与我们已经构建的产酒生香酵母菌共培养液共同添加到山西老陈醋的酒醪发酵中,使淀粉利用率提高了27%,乙醇产量提高了34%,乙酸乙酯产量提高了1倍,酒醪的产量与质量均得到了大幅度的提高。     

响应面法优化黑曲霉发酵产低聚异麦芽糖培养基

采用全因子试验、最陡爬坡试验以及Box-Behnken试验设计对黑曲霉CU-1(Aspergillus niger CU-1)发酵生产低聚异麦芽糖培养基的主要成分进行优化。结果表明:最优培养基成分为:麸皮浸汁体积分数4%、玉米浆添加量19.67g/L、NaNO3添加量2.24g/L、木薯淀粉糖化液添加量250g/L,在该培养条件下,在3.6L发酵罐中进行验证,发酵液中异麦芽糖、潘糖和异麦芽三糖总产量达到37.4%,低聚异麦芽糖总产量高达83.1%,说明Box-Behnken试验设计法用于黑曲霉发酵生产低聚异麦芽糖培养基优化是可行的,数学模型的预测值与实验观察值相符。     

Optimization of Citric Acid Production from a New Strain and Mutant of Aspergillus niger Using Solid State Fermentation

A new strain of Aspergillus niger isolated from soil and its mutant were used for citric acid production from carob under solid-state fermentation conditions. The parental strain produced 30 g/kg citric acid, while the mutant G4, selected after four rounds of gamma ray irradiation, produced 60 g/kg. Maximum citric acid production was obtained after 7 days of incubation, as the acid production was 34 and 64 g/kg for parental and mutant strains, respectively. The addition of 2% methanol increased citric acid production from the parental strain to 42 and the mutant G4 to 65 g/kg. Trace elements, namely Cu, Fe, and Zn, promoted the production of citric acid as the acid production from the parental strain increased to 46 g/kg and for mutant G4 increased to 73 g/kg after their addition. The optimum spore inoculum concentration for acid production was 10⁷ ml^?1, and the optimum pH was 5 for both parental and mutant strains.     

Optimization of Citric Acid Production from a New Strain and Mutant of Aspergillus niger Using Solid State Fermentation

A new strain of Aspergillus niger isolated from soil and its mutant were used for citric acid production from carob under solid-state fermentation conditions. The parental strain produced 30 g/kg citric acid, while the mutant G4, selected after four rounds of gamma ray irradiation, produced 60 g/kg. Maximum citric acid production was obtained after 7 days of incubation, as the acid production was 34 and 64 g/kg for parental and mutant strains, respectively. The addition of 2% methanol increased citric acid production from the parental strain to 42 and the mutant G4 to 65 g/kg. Trace elements, namely Cu, Fe, and Zn, promoted the production of citric acid as the acid production from the parental strain increased to 46 g/kg and for mutant G4 increased to 73 g/kg after their addition. The optimum spore inoculum concentration for acid production was 10⁷ ml^-1, and the optimum pH was 5 for both parental and mutant strains.     

黑曲霉发酵法制备小红栲多孔淀粉

对黑曲霉发酵法制备小红栲多孔淀粉的工艺进行了研究,并分析了多孔淀粉的形态结构、晶体特征和糊化特性。试验结果表明,在发酵培养基母液体积分数为90%的培养基中,当黑曲霉发酵至第48 h时,加入质量分数为7.0%的原淀粉后继续发酵56 h,由此制得小红栲多孔淀粉。小红栲多孔淀粉的形成过程是:酶作用于淀粉颗粒表面的凹坑形成孔洞,由浅入深,直达颗粒中心,最终形成彼此相连的桥形网状空洞结构,其上分布着孔径1μm左右的孔洞。小红栲原淀粉与多孔淀粉的X-射线衍射图谱由尖峰衍射特征和弥散衍射特征两部分组成,属C-型晶体。多孔淀粉比原淀粉的结晶度、微晶尺寸和吸热焓要大,而微晶间距和糊化温度则小。     

高产淀粉酶和蛋白酶的黑曲霉菌株的发酵条件优化

本文分离筛选到一株高产蛋白酶和淀粉酶黑曲霉菌株A020,确定该菌的最佳产酶培养基为：香蕉皮基础培养基中添加1%蛋白胨、1%麦芽糖和3×10-3 mol/L NaCl;最佳发酵条件为：30 ℃、pH 6.5、装液量150 mL/500 mL。在此条件下,150 r/min摇瓶培养4 d,测得淀粉酶、蛋白酶酶活分别为1278 U/mL和918 U/mL,淀粉酶和蛋白酶的酶活分别比优化前提高了68.2%、41.2%。     

碳源对固定化黑曲霉生产柠檬酸影响的研究

以海藻酸钙为载体包埋固定化黑曲霉AspergillusnigerW1-2细胞，用于生产柠檬酸，研究了碳源（蔗糖、葡萄糖和乳糖）及其浓度对固定化细胞生产柠檬酸的影响。结果表明，最适宜的碳源为蔗糖，其次为葡萄糖，固定化细胞利用乳糖时只生成少量柠檬酸。利用固定化细胞生产柠檬酸时，最适蔗糖浓度为120g／l，较利用游离细胞低（140g／L），并且，蔗糖浓度对固定化细胞生产柠檬酸的影响较利用游离细胞更为明显。     

黑曲霉菌体制备壳聚糖的工艺研究

研究了黑曲霉不同发酵条件(发酵温度、发酵时间、发酵pH值、摇床转速)对壳聚糖产率的影响。并对培养基组成和培养条件进行了优化试验,结果表明,最佳培养液成分为70mL玉米浆,4g葡萄糖,1.2g硫酸镁,接入8.0×108个/mL孢子;培养条件发酵温度27℃~31℃,发酵时间72h,发酵pH值7.4~7.6,摇床转速130r/min。     

以黑曲霉生产面包品质改良复合酶的研究

从粮食样品中分离并筛选出 1株可同时产生α 淀粉酶 (FAA)和葡萄糖氧化酶(GOD)的黑曲霉菌株。经试验表明 ,该菌株在适宜的条件下可稳定产生FAA 2 0 0u/mL以上 ,GOD 1 5u/ g以上。产生的 2种复合酶在pH 6～ 7下可表现最高酶活力 ,酶作用的适宜温度为 3 0～ 40℃ ,40℃下保温 3 0min酶活降低 5 0 %左右 ,在 60℃以上 2种酶均基本无活性 ,适宜用作面包制作的品质改良剂     

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.     

响应面法优化黑曲霉产纤维素酶发酵条件

利用响应面法对黑曲霉产纤维素酶的发酵条件进行优化。首先通过二水平设计的Plackett-Burman 试验分析7 种因素对黑曲霉产纤维素酶活力的影响,确定发酵温度、发酵时间、装液量为影响酶活的重要因素。然后通过响应面分析得到最优条件：发酵温度31.02℃、发酵时间73.17h、装液量100.4ml。考虑实验的实际情况,确定最优条件为发酵温度31℃、发酵时间73h、装液量100ml。优化后纤维素酶活由267.81U/ml 提高到360.02U/ml,提高34.4%。     

产聚半乳糖醛酸酶菌株Asperaillus niger M-8的筛选及产酶条件研究

从腐烂的葡萄干中定向分离筛选出适合液态发酵法生产聚半乳糖醛酸酶的菌株M-8,鉴定为黑曲霉(Asperaillus niger)。经摇瓶产酶实验可知,此菌株的产酶培养基组成及发酵条件为:果胶0.7%,NaNO30.1%,MgSO40.02%,FeSO40.001%,KH2PO40.03%,豆粉1.0%,马铃薯20.0%;培养温度28℃,初始pH7.0,装液量50mL/250mL,接种量7%(v/v),培养时间48h。在此优化发酵条件下,酶活力达964U/mL。该菌株生长周期短,产酶性状稳定,在食品领域有良好的应用前景。     

Production optimization,purification, and characterization of a novel acid protease from a fusant by Aspergillus oryzae and Aspergillus niger

The production of a novel acid protease was enhanced by 44 % through statistical optimization. The cultural parameters, such as inoculum size, temperature, moisture content, and incubation time, were 8.59 × 10⁵ g^?1 dry koji, 31 °C, 57 %, and 86 h, respectively. This novel acid protease was purified by 17 folds with a recovery yield of 33.56 % and a specific activity of 4,105.49 U mg^?1. Far-UV circular dichroic spectra revealed that this purified protease contained 7.1 % α-helix, 64.1 % β-sheet, and 32 % aperiodic coil. This novel acid protease was active over the temperature range of 35–55 °C with optimum temperature of 40 °C and was stable in the pH range of 2.5–6.5 with optimum pH of 3.5. Mn²⁺ enhanced its activity while Co²⁺ showed inhibitory effect. With casein as substrate, the kinetic parameters of K _m, V _max, energy of activation (E _a), and attenuation index of inactivation velocity by heat inducing (λ) were 0.96 mg mL^?1, 135.14 μmol min^?1 mg^?1, 64.11 kJ mol^?1, and 0.59, respectively.     

基质组分对黑曲霉发酵啤酒糟产木聚糖酶的影响

采用固态发酵培养黑曲霉，研究以啤酒糟为主要原料生产饲用木聚糖酶的最佳基质组分及其配比。结果表明，黑曲霉An54-2-1在啤酒糟：玉米芯：麸皮=6：2：2，NH4NO3 2％，Tween 800．1％的基质上，以1：1加水，接入3．5％的孢子悬液，置30℃下培养65h，产酶量达6196．803IU／g。     

Immobilization of Aspergillus niger Mycelium on Seeds for Glucoamylase Production

Mycelium of the glucoamylolytic mutant Aspergillus niger C-58-III was immobilized on wheat, rye, barley, pea, buckwheat and mustard seeds in repeated-batch flasks. After every 24th it was possible to obtain culture broth rich in glucoamylase. The highest yield of enzyme (66.4 U × ml⁻¹) was obtained on the mustard carrier. Immobilized cells were successfully reused with high level of enzyme formation being mantained for longer period (192h). Some of the variables influencing the enzymatic activity have been standardized. Enzyme productivity reached in immobilized cells of A. niger was 1.6-times higher in comparison with free cells.