五种益生菌在纤维固定化连续培养系统的共存定殖

模拟肠道的半固态生境,建立以玉米纤维为载体的固定化连续搅拌培养系统、并以非固定化连续搅拌培养系统为对照,稀释率为0.0417,分别连续培养12 d,双歧杆菌、酪酸菌、嗜酸乳杆菌、肠膜芽孢杆菌、粪肠球菌五种菌在两种系统中均可稳定共存,固定化系统固相五种菌数均高于非固定化系统,以双歧杆菌增幅最大,半固态的固定化连续培养较液态连续培养的菌相与肠道菌相较一致,能更好地模拟肠道微生态.扫描电镜观察五种菌在玉米纤维上固定形成了生物膜.     

三种益生菌混合培养及共生机理研究

确定酪酸菌、肠膜芽孢杆菌与粪肠球菌三种菌混合工艺.研究了三种菌混合培养的生长曲线,混合批式传49代、混合连续培养考察三种菌的共存稳定性.三种菌无细胞上清液彼此之间均有促进生长作用,混合培养液的菌数较单独培养增加,在稀释率0.042/h,填充床连续培养11d,三种菌可稳定共存,但批式传49代过程中,肠膜芽孢杆菌有消失现象,而酪酸菌、粪肠球菌均较传代前增加了100倍.平板打孔生长圈法、点种法实验分别表明酪酸菌、肠膜芽孢杆菌对粪肠球菌有显著的促进作用,连续培养较批式传代可更好的研究菌际关系.并得到简单易行的复方益生菌剂组方方法.     

固定化纤维二糖酶的研究

黑曲霉 (AspergillusnigerLORRE 0 12 )的孢子中富含纤维二糖酶 ,将这些孢子用海藻酸钙凝胶包埋后 ,可以方便有效地固定纤维二糖酶。固定化后的纤维二糖酶性能稳定 ,半衰期为 38d ,耐热性和适宜的pH范围均比固定化前有所增加 ,其Km 和Vmax值分别为 6 .0 1mmol L和 7.0 6mmol (min·L)。利用固定化纤维二糖酶重复分批酶解10g L的纤维二糖 ,连续 10批的酶解得率均可保持在 97%以上 ;采用连续酶解工艺 ,当稀释率为 0 .4h- 1 ,酶解得率可达 98.5 %。玉米芯经稀酸预处理后 ,其纤维残渣用里氏木霉 (Trichodermareesei)纤维素酶降解 ,酶解得率为6 9.5 % ;通过固定化纤维二糖酶的进一步作用 ,上述水解液中因纤维二糖积累所造成的反馈抑制作用得以消除 ,酶解得率提高到 84.2 % ,还原糖中葡萄糖的比例由 5 3 .6 %升至 89.5 % ,该研究结果在纤维原料酶水解工艺中具有良好的应用前景。     

固定化纤维二糖酶的研究

黑曲霉（Aspergillus niger LORRE 012）的孢子中富含纤维二糖酶,将这些孢子用海藻酸钙凝胶包埋后,可以方便有效地固定纤维二糖酶。固定化后的纤维二糖酶性能稳定,半衰期为38 d,耐热性和适宜的pH范围均比固定化前有所增加,其K_m和V_max值分别为6.01 mmol/L和7.06 mmol/(min·L)。利用固定化纤维二糖酶重复分批酶解10 g/L的纤维二糖,连续10批的酶解得率均可保持在97%以上;采用连续酶解工艺,当稀释率为0.4 h^-1,酶解得率可达98.5%。玉米芯经稀酸预处理后,其纤维残渣用里氏木霉（Trichoderma reesei）纤维素酶降解,酶解得率为69.5%;通过固定化纤维二糖酶的进一步作用,上述水解液中因纤维二糖积累所造成的反馈抑制作用得以消除,酶解得率提高到84.2%,还原糖中葡萄糖的比例由53.6%升至89.5%,该研究结果在纤维原料酶水解工艺中具有良好的应用前景。     

纤维凝胶固定化增殖酵母连续生产酒精的研究

本文比较了纤维胶固定增殖酵母与海藻酸钙凝胶球、纤维海藻酸铝凝胶与纤维海藻酸钙凝胶、以及不同厚度的纤维凝胶固定化增殖酵母的发酵结果。重点进行了纤维凝胶固定化增殖酵母连续生产酒精试验。采用１．１Ｌ柱式生物反应器,ＣＯ２排出通畅,停留时间为４小时,成熟醪中酒精含量为１０．１－１１．０％（Ｖ／Ｖ）,平均为１０．５５％,酒精生产能力为９．４ｇ／Ｌ．ｈ,总糖利用率为９４．５％。     

一株饵料微藻与益生菌混合固定化培养条件的优化

目的:一株饵料微藻与益生菌混合固定化培养条件的优化.方法:在单因素实验基础上,采用U*6(64)均匀设计表,对海藻酸钠浓度、氯化钙浓度、藻的接种量和菌的接种量进行优化实验.并采用DPS软件对实验结果进行分析,以获得适宜的混合固定化条件;并按照此优化条件对混合固定化和单藻、单菌固定化胶球中微藻和益生菌的生长速率进行比较.结果:①获得适宜的混合固定化条件为:海藻酸钠浓度4%,氯化钙浓度1.2%.藻接种量为21.9889×102个细胞,菌接种量为58.7676×109个细胞;②混合固定化胶球中藻细胞的生长速率比单藻固定化胶球中的藻的生长速率提高了18.8%;菌的平均生长速率比单菌固定化胶球中的菌的平均生长速率提高了92.6%:结论:该实验首次对饵料微藻和海洋益生菌的混合同定化培养条件进行优化.发现藻菌混合固定化胶球中藻和菌的生长速率比单独固定化均有较明显提高.实验结果说明,在混合固定化的微环境体系中,特定的藻菌株具有相互促进生长的作用.实验结果为藻菌混合固定化技术的应用和发展提供了必要的实验数据和理论基础.     

不同剂量恩诺沙星对连续培养系统中肠道菌群的影响

目的 研究不同残留剂量恩诺沙星对连续培养系统中肠道菌群数量的影响.方法 建立4套连续培养系统,接种正常人粪便于发酵罐中,连续培养肠道菌群23 d;第23天发酵罐中分别泵入含恩诺沙星剂量为0、1.25、12.5和125 mg/L的培养基,连续加药7 d,第31天停止加药.加药前10 d和加药过程中每隔2 d从4个发酵罐中取样并进行活菌计数.结果 活菌计数结果表明,空白组菌群数量稳定,说明4套连续培养系统运行稳定;低剂量组(1.25 mg/L)恩诺沙星使双歧杆菌下降3个数量级,对其他菌基本无影响;中剂量组(12.5 mg/L)中除拟杆菌外数量均有所下降,厌氧总菌、乳酸菌和肠杆菌停药前数量恢复到加药前水平,需氧总菌、双歧杆菌和肠球菌数量下降后不能恢复原初水平;高剂量组(125 mg/L)中所计数细菌数量均发生变化,需氧总菌、乳酸菌、双歧杆菌、肠球菌和拟杆菌数量下降且停药前不能恢复原初水平,厌氧总菌和肠杆菌数量先降后升,最终计数结果比加药前数量增加.结论 中国现行规定恩诺沙星的日允许摄入量(ADI)可能对人体肠道菌群造成影响.     

螺旋纤维床固定化反应器两步法生产壳聚糖酶

采用了菌体生长与产酶分步的新工艺利用里氏木霉（Trichoderma reesei） ATCC56764生产壳聚糖酶,酶活力比在相同条件下进行的一步法产酶提高了1.7倍。采用此工艺在螺旋纤维床生物反应器中进行产酶试验,酶活比采用游离细胞培养又提高了39%,达到0.246U/mL。固定化菌丝还能够长期保持活性,在重复分批操作中,经过10批共15天的产酶实验,平均每批的酶活保持在0.235U/mL左右。     

无载体固定化细胞的研究进展

以无载体固定化酵母细胞酒精连续发酵的成功工业化应用为实例,并与通常的载体固定化细胞技术比较,阐述了无载体固定化细胞技术的优缺点,系统提出了无载体固定化细胞技术的概念,进而对无载体固定化细胞技术在其它微生物发酵和动植物细胞培养过程的应用前景进行了展望。     

螺旋纤维床固定化生物反应器同时产酶降解壳聚糖的研究

采用多孔聚酯泡沫固定里氏木霉,在鼓泡柱固定化反应器中同时产酶降解壳聚糖。结果表明通过控制降解时间可以得到不同平均聚合度的降解产物。在28℃,pH4.8,通气量3vvm条件下,利用固定化反应器,在30d内连续进行10批同时产酶降解试验,结果发现壳聚糖酶活力和壳聚糖降解率能保持稳定。每批产生的壳聚糖酶活力平均达到0.15u/mL以上,壳聚糖平均降解率为73%。     

Improvement of plasmid stability of recombinant Bacillus-subtilis cells in continuous immobilized cultures

Abstract: The immobilization of recombinant Bacillus subtilis in K-carrageenan gel beads has been performed in order to study the growth conditions inside the gel beads and to improve plasmid stability. Bacterial colonies showing high cell density were studied using scanning electron microscopy. A series of continuous cultures of free and immobilized B. subtilis MT119 (pHV1431, pIL252 and pIL252 Kpn) have been developed without selection pressure. In the free-cell systems, it was found that a loss of plasmid vectors occurred after a short period. In contrast, in the immobilized cell systems, plasmid-free segregants were not detected in any of the cases during the first 80 h of the culture.     

固定化共生发酵无醇饮料的研究

以大麦和大米为主料,优质红茶为辅料,采用海藻酸钠包埋法固定酵母菌、嗜酸乳杆菌、弱氧化醋酸菌,混合装填固定化细胞反应柱,连续发酵生产无醇饮料。试验表明：麦茶汁１２°Ｂｘ,ｐＨ６５,２５℃,反应柱内固定化各菌种凝胶比例为酵母菌：嗜酸乳杆菌：弱氧化醋酸菌＝０．７：１：２,停留时间９～１３ｈ,相当于游离细胞发酵１０ｄ的效果。流出液含Ｌ－乳酸１．６５～１．９８ｇ／Ｌ,总酸２．６２４～３．０３２ｇ／Ｌ,酒精０７％～１．３２％。制成的新型发酵无醇饮料呈淡黄色,泡沫洁白细腻,含有多种人体必需氨基酸和维生素,以及具有保健作     

Continuous immobilized yeast reactor system for complete beer fermentation using spent grains and corncobs as carrier materials

Despite extensive research carried out in the last few decades, continuous beer fermentation has not yet managed to outperform the traditional batch technology. An industrial breakthrough in favour of continuous brewing using immobilized yeast could be expected only on achievement of the following process characteristics: simple design, low investment costs, flexible operation, effective process control and good product quality. The application of cheap carrier materials of by-product origin could significantly lower the investment costs of continuous fermentation systems. This work deals with a complete continuous beer fermentation system consisting of a main fermentation reactor (gas-lift) and a maturation reactor (packed-bed) containing yeast immobilized on spent grains and corncobs, respectively. The suitability of cheap carrier materials for long-term continuous brewing was proved. It was found that by fine tuning of process parameters (residence time, aeration) it was possible to adjust the flavour profile of the final product. Consumers considered the continuously fermented beer to be of a regular quality. Analytical and sensorial profiles of both continuously and batch fermented beers were compared.     

Immobilization ofβ-fructofuranosidase fromAureobasidium on DEAE-cellulose

Summary -Fructofuranosidase, which produces fructo-oligosaccharides (1-kestose and nystose) from sucrose, was purified fromAureobasidium and immobilized on DEAE-cellulose at especially high efficiency (95%). The enzymatic profiles of the immobilized enzyme were almost identical to those of the native form except that the stability was slightly improved. The immobilized enzyme was stable during long-term continuous reaction for up to 360 h.     

益生菌混合发酵条件及其对发酵胡萝卜汁色泽及风味的影响

目的 研究3株益生菌混合发酵胡萝卜汁的发酵条件对色泽、风味的影响及其贮藏特性等.方法 通过菌种配比、单因素试验及正交试验优化了胡萝卜汁的发酵条件,并利用分光测色计和气质联用仪分别研究了发酵前后胡萝卜汁的风味成分和色泽变化.结果 添加30％ (m/m)的新鲜胡萝卜汁(原液),接种3％的以1∶1∶1(v/v/v)混合的嗜热...     

Biocatalysis of silica gel-immobilized chlorophyllase in a ternary micellar system

A partially purified enzymic extract from Phaeodactylum tricornutum was immobilized on silica gel and the specific activity of chlorophyllase in its free and immobilized states were compared in a ternary micellar system. The storage stability of the free and immobilized chlorophyllase extracts, maintained at temperatures ranging from 4 to 35°C for a period of 0–20 h, was temperature-dependent. The results also showed that the specific activity of the free and immobilized chlorophyllase extracts was highest at 30°C for long-term incubation, using chlorophyll and pheophytin as substrates and that a three-fold increase in the specific activity of the immobilized chlorophyllase was observed in comparison to that obtained with the free counterpart. The findings indicated that when free and immobilized chlorophyllase extracts were recovered and reused with both substrates, the immobilized chlorophyllase extract could be recycled for longer periods of time, while the free enzyme extract showed no activity after the first cycle.     

植物生物质生物降解组合菌株的筛选研究

本研究用平板混合培养和实际降解相结合的方法筛选了较优的降解植物生物质的菌株组合。首先将6株纤维素降解菌和7株木质素降解菌两两平行划线接种到基础平板上,通过观察菌落形态,挑选出了9对能较好共存的菌株组合。随后对这9个组合进行实际降解稻草的研究,培养结束后体系中半纤维素、纤维素和木质素的含量分析结果表明AF93252 M5和XP M5这两个菌株组合较理想,它们混合培养时对稻草的降解效果均优于其单独降解稻草的效果。     

无载体固定化培养模式下HEK293细胞的生长和代谢特征

利用HEK293细胞在悬浮培养体系中下具有聚集成团的体外培养特性,在250ml的spinner flask搅拌式细胞培养瓶中以悬浮细胞团的形式实施HEK293细胞的无载体固定化培养,以细胞密度、细胞活力、细胞团粒径分布和葡萄糖比消耗率 (qglc)、乳酸比产率 (qlac)、乳酸转化率 (Ylac/glc)、氨基酸消耗为观察指标,同时设置静止培养体系作为参照,考察无载体固定化培养模式下的HEK293细胞生长和代谢特征。观察结果表明,HEK293细胞在搅拌式细胞培养瓶中无载体固定化培养和在组织培养瓶中静止贴壁培养表现为基本相同的细胞生长和代谢特征,平均粒径小于300μm的细胞团中的物质传递能够满足HEK293细胞维持正常生长和代谢的基本需要。HEK293细胞的无载体固定化培养便于实施灌注操作、提高生物反应器单位体积的生产效率。     

膜反应器培养植物细胞研究进展

本文就膜反应器在植物细胞培养中的研究现状进行了评述,并探讨了各类膜反应器存在的问题。