毕赤酵母工程菌pk53产纤溶酶发酵条件的优化

对1株产纤溶酶毕赤酵母工程菌菌株pk53,利用单因素试验和正交试验确定该菌株的适宜廉价发酵培养基为:麸皮1.5%,豆粕粉2.0%,KH2PO40.5%,MgSO4.7H2O 0.05%;发酵条件为:接种龄14 h,接种量1%,甲醇添加量1.5%,培养基装液量30 mL(250 mL三角瓶),生长pH为5.5,诱导pH为6.0;在此条件下培养,纤溶酶酶活力达429.06 U/mL,是初始发酵条件下酶活力的8.88倍。     

黄河三角洲耐高渗碱性纤维素酶产生细菌YRD-19的诱变育种和产酶条件优化

用紫外线对1株产耐盐碱纤维素酶的枯草芽孢杆菌YRD-19进行诱变育种,获得产酶能力是出发菌株5.97倍,并且产酶性能稳定的菌株YRD-19-35.进一步对其发酵条件进行研究,优化了培养基和培养条件.实验结果表明,优化培养基为:1.5%乳糖,1.5%蛋白胨,NaCl:KH2PO4=5:1,添加量为0.55%;优化培养条件为:接种量为2%,发酵温度为37℃,培养基初始pH为8.0,种子活化时间为24h,发酵时间为48h,装液量为50mL,摇床转速为200r/min时菌株YRD-19-35产酶的酶活力达到最高.在上述条件下,纤维素酶活力可达182.705U/g.     

酶解玉米淀粉发酵酒精工艺条件的研究

研究复合酶发酵玉米淀粉生产酒精的工艺,通过单因素试验和正交试验确定了酶解玉米淀粉发酵酒精的最佳工艺条件,即玉米淀粉粉碎度60目、料水比1:3、酶加量1.5%(玉米淀粉原料)、发酵温度35℃,发酵时间51 h、pH4.8,在此条件下发酵酒精度为11.5%vol.     

葛根酒的开发

以葛根作为酿酒原料,对葛根酒研制中的酶解液化、糖化、酒精发酵等工艺过程进行了研究。确定了酶解液化时料液比为1∶1.5,纤维素酶添加量为10 u/g,酶解1.5h,α-淀粉酶添加量为0.7%,液化4 h;糖化过程中糖化酶添加量为3%,糖化3 h,得到还原糖含量较高的糖化醪;再通过正交试验得到酒精发酵的工艺方案:糖化醪初始糖度为18%,2∶1的混合酵母接种量为5%,发酵温度25℃,发酵时间48 h。该方法能在较短的时间内酿制出具有葛根风味的低度发酵酒,该酒葛根味浓郁、色泽清亮、口感醇厚。     

富含海带多糖的乳酸发酵饮料的研究

本研究以海带为主要原料,采用乳酸菌发酵生产富含海带多糖的饮料,探讨了海带的酶解条件以及各因素对粗海带多糖提取量的影响。研究乳酸菌在海带水解液中生长产酸及脱腥效果,并确定了发酵饮料的配方。结果表明:海带多糖的最佳提取条件为加入海带粉重1.5%的复合酶,在pH6.0、40℃酶解6h,粗海带多糖的得率可达10.89%。其中复合酶(纤维素酶、果胶酶和木瓜蛋白酶)的最佳配比为2:1:2。海带多糖饮料发酵的最佳条件为在海带水解液中加入乳清粉0.5%,蔗糖7%,乳酸菌粉为1mg/100ml,发酵温度为40℃,发酵时间为24h,乳酸的产量为0.7%左右。     

红芝固态发酵产漆酶条件研究

对红芝固态发酵产漆酶的培养基和培养条件进行了研究。结果表明,适宜的固态发酵培养基为:以1.5∶1甘蔗渣和麦麸为基质,葡萄糖0.5%、硫酸铵5%、CuSO4.5H2O 0.01%、培养基含水率73%;适宜的固态培养条件为:初始pH值4.0,接种量20%(V∶W),28℃静置培养8 d,酶活达到最高23803 U/g干曲。     

辣木醋酿造工艺的研究

以辣木叶粉、红糖为原料,采用半固态发酵方法,通过正交试验,确定原料液酶解、酒精发酵和醋酸发酵的最佳工艺条件。辣木醋原料液酶解的最佳工艺参数为:辣木叶粉与水的质量比为1∶10,复合酶由纤维素酶、木聚糖酶和β-葡聚糖酶组成,复合酶的添加量为0.4g/L,酶解温度为50℃,时间为1.5h。酒精发酵的最佳工艺参数为:酵母菌接种量0.3%,发酵温度30℃,发酵时间7天。醋酸发酵的最佳工艺条件为:醋酸菌接种量10%,初始酒精度9%,发酵温度29℃,发酵时间6天。     

以红曲霉酯化酶催化合成乳酸乙酯

利用自汾酒大曲中分离获得的产酯能力较高的红曲霉菌株,采用正交试验法,以酯化酶活性为检测指标,优化了发酵培养基配方和培养条件,确定了最佳发酵培养基成分质量配比为麸皮:水=1:1;最佳发酵条件为:红曲霉接种量为1%,发酵温度为30℃,发酵4 d,制得酯化酶酶制剂。在此基础上,采用响应面优化法对其酯化酶的催化条件进行了优化,确定了最佳催化条件为:乙醇和乳酸的摩尔比为6,加酶量1.5%,反应时间60h,反应温度30℃,乳酸乙酯生成量可达到3.38 g/L。     

弹性蛋白酶高产菌株摇瓶发酵条件优化及弹性蛋白酶性质的初涉研究

运用响应面法对一株枯草芽孢杆菌(Bacillus subtilis)发酵培养条件进行了优化,这株枯草芽孢杆菌产弹性蛋白酶的最适发酵条件为:1.5%葡萄糖、1.5%酵母膏,起始pH为6.5,最适发酵温度为36.5℃,并对由这株枯草芽孢杆菌发酵生产的弹性蛋白酶进行了研究,发现由该株菌发酵得到的弹性蛋白酶在碱性条件下活性较好;在37℃以下时稳定性较好.     

白曲霉Asp-amy1固体发酵生产酸性淀粉酶的初步研究

利用白曲霉菌株Asp-amy1进行固体发酵生产酸性淀粉酶,对白曲霉固体发酵条件进行了优化,初步确定菌株产酶的优化培养基为:7.5%的玉米粉,1.5%的蛋白胨,发酵曲含水量为50%,发酵起始pH5.5.菌株的最佳接种量为40%(干基计),发酵时间由72 h缩短到48 h,菌体生长迅速,产酶能力强,酶活达1000 U/g干曲.薄层层析生成的液化产物,主要以G2-G7为主,淀粉液化后都生成了小分子的糊精和寡糖类;产物薄层分析可初步确定所产酶为液化型酶.     

木薯原料柠檬酸发酵补料新工艺的研究

选择计量罐式连续流加补料系统,采用新选育的黑曲霉(Aspergillus niger)Wml-016菌株在50 L自动发酵罐上研究间歇补料对发酵的影响。利用中心复合设计和响应面分析方法,实验得出木薯原料柠檬酸补料发酵的优化条件:发酵到第36 h开始进行4次流加补料,间隔时间为1.5 h,补入DE值为80的木薯水解液和质量浓度为0.04%的(NH4)2SO4。采用上述工艺发酵产酸率达到18.5%,残糖为0.2%,周期仅为64 h,结果明显优于分批发酵。     

基于主元分析和模糊模型的链霉素发酵过程建模

基于主元分析和模糊模型 ,提出了一种简单而有效的链霉素发酵过程产物浓度的预报方法 .该方法采用主元分析压缩关联程度高且含有测量噪声的实际工业生产数据 ,筛选出影响产物浓度的主要过程变量 ,构造了模糊分段线性模型的产物浓度估计器 .与线性多元回归模型相比 ,模糊模型更适合作为间歇发酵过程的状态估计器 .     

Fed‐batch l‐(+)‐lactic acid fermentation of brewer's spent grain hydrolysate

Brewer's spent grain (BSG) hydrolysates were used for l ‐(+)‐lactic acid (LA) fermentation by Lactobacillus rhamnosus ATCC 7469. The aim of this study was to evaluate fed‐batch LA fermentation of BSG hydrolysate with the addition of glucose, glucose and yeast extract, and wort during LA fermentation and its effect on fermentation parameters such as LA concentration, its volumetric productivity and yield, and L. rhamnosus cell viability. The highest LA yield, volumetric productivity and concentration of 93.3%, 2.0 g/L/h, and 116.1 g/L, respectively, were achieved with glucose and yeast extract addition during fermentation. In fed‐batch fermentation with glucose and yeast extract addition significantly higher LA concentration, yield and volumetric productivity (by 194.8; 2.2, and 20.7%, respectively) were achieved compared with batch fermentation. The results indicated that fed‐batch fermentation could be used to increase LA fermentation efficiency. Copyright © 2017 The Institute of Brewing & Distilling     

Influence of feeding varying levels of Amaferm on performance of lactating dairy cows.

Amaferm, a fermentation extract of Aspergillus oryzae, was fed as a top-dressing to dairy cows at 0, 1.5, 3, and 6 g/d in two lactation trials using 64 cows in 1989. Lactation trial 1 was conducted in the spring (March to May) and used 40 cows averaging 75 DIM for a 70-d treatment period. Lactation trial 2 was during the summer (June to July). Twenty-four cows averaging 140 DIM were employed in a 60-d study. Measurements included milk yield, feed intake, BW, rectal temperatures, respiration rate, and digestibility of CP, NDF, and DM. None of the levels of Amaferm had a significant effect on milk yield or composition, BW changes, or digestion coefficients in either trial. Cows fed 1.5 g/d of Amaferm had a higher DMI than those receiving 0 or 6 g in trial 1, and respiration rates were significantly higher for cows fed 3 g/d of Amaferm in trial 2. Under the conditions of this study, none of the levels of Amaferm affected the performance of lactating cows. Further elucidation of factors influencing response to Amaferm is needed.     

指数流加模型在乙醇气提发酵过程中的应用研究

通过实验选择并考核了一个指数流加模型 ,同时也对比地考察了均速流加方式的发酵效果。结果表明 ,指数流加相比匀速流加过程的细胞生物量平均浓度增加了 1 2 2倍 ,乙醇生产速率和糖消耗速率分别提高到 3 0 1 g/(h·L)和 6 2 1g/(h·L) ,是匀速流加时的 1 2倍和 1 1 9倍。研究表明 ,在乙醇气提发酵过程中 ,如果选用适当的指数流加模型 ,就能够消除发酵过程中底物和产物的双抑制作用 ,简单而有效地改进现有的在线分离乙醇的连续发酵工艺 ,提高乙醇生产速率     

酵母流加发酵过程中的模糊控制器

通过分析酵母发酵过程中的影响因素,建立了控制酵母发酵过程中流加速率的模糊控制器.该模糊控制器的模糊规则可以根据专家经验方便地修改以提高控制效果.实验表明在模糊控制器控制下酵母产量比恒速流加时提高了一倍.     

一株产高浓度酒精酵母的流加发酵策略初步研究

对一株产高浓度酒精的酿酒酵母的流加发酵策略进行了初步研究，采用均匀试验设计方法考察了流加速率、流加葡萄糖浓度以及流加初始葡萄糖浓度对高浓度酒精发酵的影响，以得率为评价指标，用SPSS进行回归分析，得到最优流加条件为流加速率114．3mL/H，流加葡萄糖浓度44．8％，初始葡萄糖浓度9．7％。     

L-色氨酸产生菌分批发酵动力学模型

基于 3 0L的发酵罐分批发酵实验数据 ,根据已建立的L 色氨酸发酵数学模型 ,应用MATLAB软件对模型进行最优参数估计和非线性曲线拟合 ,得到的结果相对误差较小 ,所建立的分批发酵动力学模型能较好地反映L 色氨酸分批发酵的过程     

不同补料方式对酿酒酵母高密度发酵的影响

以酿酒酵母为发酵菌种,使用自主优化筛选配制的糖蜜培养基,分别采用残糖反馈分批补料和连续流加补料方式,优化发酵工艺条件以提高发酵液中菌体密度。残糖反馈分批补料,拟设定3个梯度,分别控制对数期发酵液中残糖含量在0.5%～1.5%,1.0%～2.0%,1.5%～2.5%。三次试验结果分别为,试验1菌体培养32 h时达到最大生物量,为28.88 g/L;试验2菌体培养52 h时达到最大生物量,为27.43 g/L;试验3菌体培养24 h时达到最大生物量,为22.06 g/L。通过连续流加补料培养菌体,结果培养30 h时达到最大生物量,为29.29 g/L。     

Potential of fermentation byproducts as nitrogen supplements for lactating dairy cows

Two feeding trials evaluated several byproducts from commercial amino acid fermentations as N supplements for lactating cows. Trial 1 was a replicated 5 x 5 Latin square that used 2-wk periods and 25 Holstein cows (five with ruminal cannulae) fed diets containing [dry matter (DM) basis] 28% alfalfa silage, 31% corn silage, 28% high moisture ear corn plus 4 percentage units of crude protein (CP) from: soybean meal, urea, commercial fermentation byproduct 1 or 2, or a blend of fermentation byproducts plus wheat middlings. Diets averaged 15.1% CP and 32% neutral detergent fiber. Intake of DM, body weight (BW) gain, and yield of milk and milk components were greatest for cows fed soybean meal; animal performance was similar with urea, byproduct 1 and the byproduct blend. Intake, BW change, and yield of milk and protein when cows were fed byproduct 2 were lower than when fed urea. Urine output (estimated with creatinine in spot urine samples) was greater on fermentation byproduct 1 and the byproduct blend. There were no differences due to N source in microbial synthesis (based on estimated purine derivative excretion), in situ digestion of alfalfa hay DM, or molar proportions of ruminal volatile fatty acids. Trial 2 was a replicated 5 x 5 Latin square using 2-wk periods and 10 Holstein cows fed diets containing (DM basis) 37% alfalfa silage, 28% corn silage, 29% high moisture ear corn plus 2 percentage units of CP from urea, fermentation byproduct 1, or one of three blends of fermentation byproducts plus wheat middlings. Except for greater DM intake in cows fed the byproduct blends, performance and urinary metabolite excretion did not differ because of N supplement. Relative to other fermentation byproducts and urea, byproduct 1 resulted in reduced milk urea N in both trials. Under the conditions of these trials, fermentation byproducts were less effective than soybean meal, and no more effective than urea, as N supplements.