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酿酒酵母属(S. cereviae)变异株和粟酒裂殖酵母属(S. pombe)变异株进行属间原生质体融合得到融合株SPSC,该融合株比S. cereviae具有强的自身絮凝能力。以葡萄糖浓度150g/L的底物在30~44℃的温度范围内进行摇瓶厌氧发酵,获得最佳温度范围为34~38℃,最高发酵温度为40℃。在有效容积2.35L悬浮床反应器中,在pH值3.0~5.0范围内进行连续发酵,获得最适发酵pH为3.5~4.5。 相似文献
73.
自养黄杆菌合成羟基丁酸和羟基戊酸共聚体的发酵研究 总被引:14,自引:2,他引:12
采用本实验室从土壤中分离到的一株自养黄杆菌进行了羟基丁酸和羟基戊酸共聚体〔P(HB-co-HV)〕的发酵试验。实验结果表明,该菌株是自养黄杆菌葡萄糖运输突变株,可以葡萄糖、果糖、蔗糖、麦芽糖、乙酸盐、乳酸盐和苹果酸盐作为唯一碳源,尤以葡萄糖和果糖效果最佳。硫酸铵、氯化铵和蛋白胨等不同氮源不影响其生长,却影响细胞中P(HB-co-HV)的含量和P(HB-co-HV)中HV/HB的比例。应用两阶段控制方式,经42h的补料分批发酵,细胞浓度达34.9g·L~(-1),P(HB-co-HV)浓度达25.28g·L~(-1)。细胞和P(HB-co-HV)生产速率系数分别为0.83g·L~(-1)”·h~(-1)和0.61g·L~(-1)·h~(-1)。以基质为基准的细胞得率系数(Yx/s)、产物得率系数(Yp/s)和以干细胞为基准的产物得率系数(Yp/x)分别为0.283(g/g)、0.174(g/g)和0.73(g/g)。改变培养基中碳氮源组分可将P(HB-co-HV)中HB的含量调节在24%~78%之间。 相似文献
74.
Production of fuel alcohol from oats by fermentation 总被引:1,自引:0,他引:1
Very high gravity (>30 g dissolved solids per 100 ml) mashes were prepared from hulled and hulless oats and fermented at 20° C with active dry yeast to produce ethanol. Excessive viscosity development during mashing was prevented by hydrolyzing -glucan with crude preparations of -glucanase or Biocellulase. Both these preparations possessed endo--glucanase activity. By using these enzymes and by decreasing the water to grain ratio, very high gravity mashes with low viscosity were prepared. Unlike wheat and barley mashes, oat mashes contained sufficient amounts of assimilable nitrogen to promote a fast rate of fermentation. The free amino nitrogen (FAN) content of oat mash could be predicted by the equation, mg FAN L–1=8.9n wheren is the number of grams of dissolved solids in 100 ml of mash supernatant fluid. Ethanol yields of 353.2±3.7 L and 317.6±1.3 L were obtained per tonne (dry weight basis) of hulless (59.8% starch) and hulled (50.8% starch) oats respectively. The efficiency of conversion of starch to ethanol was the same in normal and very high gravity mashes. 相似文献
75.
H. Drechsel M. Tschierske A. Thieken G. Jung H. Zähner G. Winkelmann 《Journal of industrial microbiology & biotechnology》1995,14(2):105-112
Summary Rhizoferrin is a novel carboxylate-type siderophore which has recently been isolated fromRhizopus microsporus and other fungi of the Mucorales (Zygomycetes). The present investigation shows that a variety of rhizoferrin analogs can be produced by directed fermentation. Thus both the diaminobutane backbone and the citric acid side chains of rhizoferrin have been substituted by diamine and citric acid analogs added to the culture medium. The new ligands as well as their iron complexes have been characterized by physicochemical methods. Conditions of precursor incorporation and implications for the biosynthesis of the new siderophores are discussed. 相似文献
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Alfons J. M. Stams 《Antonie van Leeuwenhoek》1994,66(1-3):271-294
In methanogenic environments organic matter is degraded by associations of fermenting, acetogenic and methanogenic bacteria. Hydrogen and formate consumption, and to some extent also acetate consumption, by methanogens affects the metabolism of the other bacteria. Product formation of fermenting bacteria is shifted to more oxidized products, while acetogenic bacteria are only able to metabolize compounds when methanogens consume hydrogen and formate efficiently. These types of metabolic interaction between anaerobic bacteria is due to the fact that the oxidation of NADH and FADH2 coupled to proton or bicarbonate reduction is thermodynamically only feasible at low hydrogen and formate concentrations. Syntrophic relationships which depend on interspecies hydrogen or formate transfer were described for the degradation of e.g. fatty acids, amino acids and aromatic compounds. 相似文献
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