固定化丙酸菌的初步研究

对丙酸菌固定化的条件进行了研究,固定于海藻酸钠、琼脂、卡拉胶3种载体上的丙酸菌的分批发酵的结果表明,海藻酸钠包埋丙酸菌活性最高。在文中实验条件下,用于固定化的最适海藻酸钠的浓度为4 %。固定化颗粒的直径大小,固定化细胞的质量与发酵液体积比等对产酸速率都有影响。4℃储存4 5d的固定化细胞,其发酵产丙酸活性经4批实验后仍与储存前基本相同。在最适条件下,连续13批次的发酵实验表明,固定化细胞稳定,凝胶颗粒强度无变化,适于连续化生产。与游离丙酸菌比较,固定化细胞的丙酸生成速度加快,丙酸产量明显提高     

固定化酵母菌和醋酸杆菌发酵食醋工艺研究

用海藻酸钠包埋酵母菌，滴入1％～9％的钙离子液固化，固定时间4h，连续酒精发酵凝胶颗粒的完整性和弹性尚好。用2．5％的海藻酸纳与4％的PVA混合作醋酸杆菌包埋剂，滴入2％～4％的钙离子硼酸液制备凝胶球，固化9h～10h，成型性和机械强度很好。固定化醋酸杆菌分批发酵50h，产醋酸达4．06g／100mL，重复使用25d，固定化细胞保持高的活力。     

海藻酸钙法固定化乳酸菌发酵制备L-乳酸的研究

在单因素实验的基础上,利用响应曲面法,对海藻酸钙法固定化植物乳杆菌发酵生产L-乳酸的条件进行优化.建立了显著影响因素和响应值之间的函数关系,得到回归方程.结果表明,最适合乳酸发酵的固定化细胞制作条件为:海藻酸钠浓度2%、包埋量20mL菌悬液/mL凝胶、固定化增殖时间22h、颗粒直径1mm左右、氯化钙浓度2%.     

固定化细胞技术应用于芒果醋的研究

采用凝胶包埋法对醋杆菌进行固定化,以芒果酒为原料,对固定化醋杆菌发酵芒果醋进行了研究.结果表明,固定化的最适条件为:2%的海藻酸钠、4%的CaCl2及5%的醋酸菌填充量;与传统发酵芒果醋对比,固定化方法发酵芒果醋的产酸率提高了45%;在连续发酵芒果醋的试验中,最短只需22.5h,芒果醋酸度即达到3.46%,连续发酵10个批次,产酸率基本保持在0.3g/(L·h)左右.     

固定化醋酸杆菌发酵条件的研究

以海藻酸钠为载体,采用包埋法固定化醋酸杆菌,利用固定化醋酸杆菌进行醋酸发酵,寻求其最优工艺参数。在单因素试验的基础上,确定接种量、起始乙醇体积分数和发酵温度为主要影响因素,采用响应面法的Box-Behnken试验设计对发酵条件进行优化。建立产酸量与影响因子的多元二次回归方程,得到固定化醋酸杆菌进行醋酸发酵的最佳条件为:接种量7.88g/100mL,起始乙醇体积分数4.63%,发酵温度32℃,在此条件下,产酸量的理论值为3.56g/100mL。对最佳发酵条件进行实验验证,结果产酸量为3.51g/100mL,与模型预测基本相符。因此,利用响应面分析方法得到的固定化醋酸杆菌发酵条件参数可靠,具有实用参考价值。     

固定化地衣芽孢杆菌产弹性蛋白酶的研究

为提高弹性蛋白酶的发酵产能,构建地衣芽孢杆菌连续发酵产弹性蛋白酶的生产工艺,本研究采用单因素试验及响应面分析法对地衣芽孢杆菌凝胶包埋固定化的工艺进行探讨,并对固定化细胞的发酵产酶性能进行分析。结果表明,地衣芽孢杆菌的适宜固定化体系是聚乙烯醇（polyving akohol,PVA）、海藻酸钠（sodium alginate,SA）和CaCl2,质量分数分别为8.22%、2.27%和2.42%,固定化交联剂硼酸的质量分数为4%;固定化地衣芽孢杆菌发酵产弹性蛋白酶的活力可达到386 U/mL,是相同接种量的游离细胞发酵酶活力的87%;固定化的地衣芽孢杆菌凝胶球具有很好的稳定性,在摇瓶发酵的条件下可连续使用10 批次以上。以上结果表明,复合凝胶包埋制备的固定化地衣芽孢杆菌细胞可用于连续发酵产弹性蛋白酶的生产工艺。     

阶段性硬化固定化酵母细胞传质效果的研究

用海藻酸钠-PVA混合载体包埋制备固定化酵母细胞颗粒,比较了阶段性硬化和混合凝固剂同时硬化两种方法的固定化细胞颗粒的通透性及传质效果.电镜扫描和正交实验结果表明,阶段性硬化可提高固定化细胞颗粒的通透性及传质效果;最佳固定化条件为细胞颗粒在2%(w/w)CaCl2溶液成型后,立即在3%(w/w)的硼酸溶液中硬化24 h;固定化酵母细胞发酵过程产酒和机械性能的稳定.     

磷酸根离子对固定化酵母细胞传质效果改善的研究

利用磷酸根离子对海藻酸钙凝胶有软化、破坏作用的原理,来处理用海藻酸钠-PVA混合载体包埋制得的固定化细胞颗粒,可有效降低凝胶结构的紧密程度,增强其通透性,获得较好的传质效果,通过扫描电镜对凝胶颗粒结构的袁征证实了实验效果。实验得出最好的磷酸根离子处理方式为：用0．8mol／L KH2PO4浸泡固定化细胞颗粒24h后再进行发酵生产。最后用多批次发酵实验验证了用磷酸根离子处理后的固定化酵母细胞的产酒、机械性能的稳定性。     

固定化技术应用于食醋的可行性研究

固定化醋酸菌应用于醋酸(或食醋)发酵的研究,目前仍处于实验阶段。1980年日本小须贺惇一等报道了用K-角叉胶包埋纹膜醋酸菌,在150毫升反应器中进行醋酸连续发酵的试验结果。国内1987年大连轻工业学院严复等报道了用海藻酸钠包埋醋酸菌在250毫升锥形瓶中进行振荡醋酸发酵情况。我们从1986年开始进行了用海藻酸钠固定醋酸菌,连续发     

固定化醋酸菌生产食醋的研究

用海藻酸钠、聚丙烯纤维、氧化钛、硅酸铝、辉绿岩作载体,采用包埋法或吸附法固定醋酸菌。制造食醋较传统工艺缩短发酵时间二分之一以上,简化了食醋生产的种子扩大培养过程,适于连续化生产。探索了固定化载体的选择和防止变性问题,探讨了固定化细胞的装量。     

固定化多菌种及其产酸研究

从优质窖泥中分离得到多种菌株,利用活细胞固定化技术对混合菌株的产酸情况进行了研究。分别以改良的巴克培养基和酒糟浸出液为基础,通过改变培养基成份,用气相色谱分析检测不同发酵条件下各种有机酸的变化情况。结果表明:甲酸、戊酸对混合菌种产酸有抑制作用,乙酸钠与固定化菌株产酸呈正相关:以乙酸+乳酸、乙酸+丙酸、乙酸+丁酸、丙酸+丁酸混合作为碳源,对己酸的生成有明显的促进作用;菌株对底物的转化趋势是:乙酸→丁酸→己酸;同时还发现,氮、磷对固定化菌株有机酸的产生影响很大。此外,对固定化菌株发酵酒糟浸出液的有机酸产生情况进行研究,结果较为理想,可用于浓香型白酒的再生产。     

APPLICABILITY OF ALGINATE ENTRAPPED YEAST CELLS FOR THE PRODUCTION OF LACTOSE-HYDROLYZED MILK

To overcome the problem of enzyme extraction and poor permeability of cell membrane to lactose, permeabilized Kluyveromyces marxianus NCIM 3465 cells as a source of β‐D‐galactosidase were employed for the production of lactose‐hydrolyzed milk. In view of the advantages of an immobilized cell system over a free cell system, the yeast cells were entrapped in alginate gel for their subsequent use in lactose hydrolysis. Different process parameters (alginate concentration, bead size, biomass load, temperature, agitation and incubation time) were monitored to enhance lactose hydrolysis in milk. Maximum lactose hydrolysis (87.9%) was observed with yeast cells immobilized in 2% (w/v) alginate concentration with a bead size of 2.90 mm at 30C under agitation (80 rpm) after 150 min of incubation. The developed system was highly stable and the alginate entrapped yeast cells can be recycled up to the eight cycle without any marked change in their ability to carry out the lactose hydrolysis.     

Comparative Production of Sugarcane Vinegar by Different Immobilization Techniques

Sugarcane juice was converted to ethanol by Saccharomyces cerevisiae producing 8% (v/v) ethanol. This ethanol was used for vinegar production using adsorbed (bagasse, corn cobs and wood shavings) and entrapped (calcium alginate) cells of Acetobacter aceti NRRL 746. All three adsorbed carrier materials were statistically similar for acetic acid production and produced acidity from 5.9 to 6.7% after 28 days of submerged fermentation. By recycling bagasse adsorbed cells, the time of acetic acid fermentation was reduced to 13 days. Semi‐continuous fermentation of bagasse adsorbed cells using a packed bed column further reduced the fermentation time to 80 h.     

Mead production: fermentative performance of yeasts entrapped in different concentrations of alginate

Mead is an alcoholic drink known since ancient times, produced by yeast fermenting diluted honey. However, the production of mead has suffered in recent years, partially owing to the lack of scientific progress in this field. In this study, two strains of Saccharomyces cerevisiae, QA23 and ICVD47, were immobilized in 2 or 4% (w/v) alginate beads to assess the most effective alginate concentration for yeast immobilization to produce mead. Neither of the alginate concentrations was able to prevent cell leakage from the beads. The fermentation length was 120 h for both yeast strains. In all cases, at the end of the fermentation, the number of cells entrapped in the beads was higher than the number of free cells, and the total 4% alginate bead wet weight was significantly higher than the 2% alginate bead wet weight. In addition, the evaluation of mead quality showed that the yeast strain had significantly more influence on the physicochemical characteristics than the alginate concentration. Although the yeasts immobilized in the two alginate concentrations were able to perform the fermentation, further research is needed in order to understand the evolution of the yeast population inside the beads throughout the fermentative process. Copyright © 2014 The Institute of Brewing & Distilling     

Cell release from alginate immobilized Lactococcus lactis ssp. lactis in chitosan and alginate coated beads

The effects of chitosan and alginate coatings of alginate beads with entrapped Lactococcus lactis ssp. lactis were studied in batch and continuous fermentations. Chitosan coating reduced the final concentrations of free cells, the initial release of free cells and the rate of lactate production in milk fermented batch-wise to a final pH of 4.7 in five consecutive batch fermentations. An alternative experimental system based on continuous fermentation with controlled pH and a high dilution rate was developed to better study the phenomenon of cell release. To estimate the effects of different bead coatings on cell release, alginate beads were coated with chitosan or alginate, or sequentially with chitosan/alginate or chitosan/alginate/chitosan. Chitosan coating alone seemed to reduce the rate of cell release only in the early stages of the fermentation, while sequential coatings with chitosan and alginate showed significant reduction throughout the whole test period. To examine whether the observed effects of bead coating could be explained only by a decrease in cell activity, the ratios between the rate of cell release and the rate of lactate production were examined during the fermentations for the different beads. This ratio showed qualitatively the same behavior as direct results of volumetric cell release.     

固定化技术在乙酸乙酯调味酒酿造过程中的应用

以海藻酸钙(calcium alginate,CA)和聚乙烯醇(polyvinyl alcohol,PVA)为共聚物,对异常汉逊酵母(Hansenula anomala)进行乙酸乙酯(ethyl acetate,EA)调味酒的固定化发酵.研究了海藻酸钠(sodium alginate,SA)、PVA、CaCl2浓度对固定化发酵的影响,SA-PVA和CaCl2-H3BO3浓度(正交试验法)、固定化时间及固定化颗粒包埋量对EA调味酒发酵的影响.进行重复发酵试验,确定最佳固定化方法为:以1.5％CaCl2-饱和H3BO3为交联剂,按2％SA-9％PVA混合材料的配比制作固定化颗粒,固定6h,包埋量为10进行单菌株发酵,得到EA质量浓度为3.99g/L.同时,比较分析了固定化和传统游离发酵酵母菌增殖情况及其成品酒(清香型)的各项品质指标.结果表明,固定化发酵EA调味酒不仅可以提高菌株发酵力,还可减少育种环节,提高生产效率和产品品质,为调味酒的生产应用奠定了基础.     

PEI对固定化增殖细胞性质的影响

以海藻酸钙为载体包埋黑曲霉AS0 0 2 3孢子 ,培养后得到的固定化增殖细胞用于生产低聚果糖 .利用材料试验仪研究了聚乙烯亚胺 (PEI)对固定化增殖细胞强度的影响 ,并研究了PEI对固定化增殖细胞酶活及最适 pH值的影响 .结果表明 ,经PEI处理后 ,尽管固定化增殖细胞酶活略有降低 ,最适 pH值由 5.5降至 4 .0 ,但凝胶强度有明显改善 .起始机械强度由 0 .0 6N/粒增加到 0 .2 79N/粒 ,而机械强度衰减率仅为未处理组的 9.2 7% .     

固定枯草芽孢杆菌发酵生产类细菌素的研究

以海藻酸钙为材料,固定枯草芽孢杆菌(Bacillussubtilis)LL18-4,研究了不同条件下类细菌素效价的变化情况。结果表明,利用3%海藻酸钠在2%CaCl2条件下,得到固定化细胞颗粒的类细菌素效价和稳定性较好,可维持216h无破裂;对其固定化颗粒进行发酵条件的研究发现,培养温度37℃,pH值6.5,接种量1%,72h静止培养,固定菌所产类细菌素的抑菌活性高,最高效价为334.2u/mL。通过216h3批次循环的半连续培养后,固定菌活性仍能维持在260.9u/mL以上。     

固定化液态发酵红曲霉色素的研究

对红曲霉F4018菌株固定化(用海藻酸钙包埋法固定)液态发酵生产色素进行了研究.其整个发酵过程分为3个阶段:0～48 h为快速生长期,并伴随少量色素合成;48～96 h为平衡期,大量合成色素,占总色素的85%以上,其中红色素的合成速度超过黄色素的合成速度;96 h后衰老期,色素色价开始下降,但下降缓慢,持续时间长,发酵液的色调偏红.同传统的液态发酵具有两方面优势:(1)具有一样的生长期,较长、稳定的平衡期和缓慢的衰老期,非常有利于色素产量的提高.(2)多批次发酵后固定化细胞的稳定性表现仍然良好,适合现代工业化大规模生产的需要.