摘要
The microfiltration characteristics of Bacillus subtilis broths under different culture conditions were studied. In the no medium addition culture condition the major component in the broth was sole B. subtilis cells. The filtration curve of dt/dv vs. v (reciprocal of filtration flux vs. filtrate volume) can be divided into three regions. After a short relaxation time the tangent slope increases drastically. This implies that significant cell deformation and cake compression occurs in the second region. The average specific cake filtration resistance will reach the maximum value at the filtration curve inflection point. The cake compressibility gradually decreases in the third region because most solid compressive pressures are depleted by the formed compact cake. In the medium addition culture condition the B. subtilis cells and extracellular polymer substances (EPS) flocs concentrations in the broth increase markedly with culture time. The filtration curve tangent slope increases continuously during the entire filtration period because of the highly compressible cake. All proteins in the extra-cellular polymeric substances are retained by the filter cake and membrane during a filtration, while most polysaccharides have the opportunity to penetrate into the filtrate when the culture time exceeds 1 day. Polysaccharide rejection increases with increasing filtration pressure for the 1-day culture broth. However, the filtration pressure has a trivial effect on the polysaccharide rejection for longer culture times. The filter cake resistance formed by B. subtilis cells and EPS flocs plays an important role in determining the overall filtration resistance. A longer culture time and lower filtration pressure are beneficial for protein/polysaccharide separation using microfiltration.
摘要译文
的不同培养条件下的枯草芽孢杆菌肉汤微量过滤特性进行了研究。在无介质除了培养条件的肉汤的主要成分是唯一的B.枯草芽孢杆菌细胞。的DT / DV与V（过滤通量与滤液体积的倒数）的过滤曲线可以分成三个区域。后很短的弛豫时间的切线斜率增大急剧。这意味着，显著细胞变形和蛋糕压缩发生在第二区域中。的平均比滤饼过滤阻力将达到在过滤曲线拐点的最大值。滤饼可压缩在第三区域逐渐减小，因为大多数的固体压缩压力由所形成的致密滤饼耗尽。在中除了培养条件的B.枯草芽孢杆菌细胞和细胞外高分子物质（EPS）的絮凝物浓度肉汤显着增加与培养时间。过滤曲线的切线斜率时，因为高度可压缩蛋糕的整个过滤周期持续增加。在细胞外聚合物质的所有蛋白质都是由滤饼和膜过滤过程中保留下来，而大多数多糖有机会渗入滤液时培养时间超过1天。多糖排斥增加而增加过滤压力为1天的培养肉汤。然而，的过滤压力对多糖排斥更长培养次微不足道的影响。由B所形成的滤饼阻力芽孢杆菌细胞和EPS絮凝物在确定的总过滤阻力的重要作用。更长的培养时间和较低的过滤压力有利于利用微滤蛋白质/多糖的分离。
Kuo-Jen Hwang; Chung-Yi Wang. Microfiltration characteristics of Bacillus subtilis fermentation broths[J]. Journal of the Taiwan Institute of Chemical Engineers, 2012,43(3): 347-353