Wiley
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Các bài báo tiêu biểu
Nghiên cứu động học của quá trình lên men axit lactic: Quá trình lên men gián đoạn ở pH kiểm soát Tóm tắt Dữ liệu động học là cần thiết để phát triển sự hiểu biết cơ bản về quá trình lên men và cho phép thiết kế hợp lý các quá trình lên men liên tục. Động học của quá trình lên men glucose thành axit lactic đã được nghiên cứu ở sáu mức pH ổn định từ 4,5 đến 6,0 thông qua việc đo tốc độ tức thời của sự phát triển vi khuẩn và sự hình thành axit lactic trong suốt mỗi quá trình lên men. Phát hiện rằng tốc độ tức thời của sự hình thành axit dP /dt , có thể liên quan đến tốc độ tức thời của sự phát triển vi khuẩn dN /dt , và mật độ vi khuẩn N , trong suốt quá trình lên men ở một pH nhất định, qua biểu thức
nơi mà các hằng số α và β được xác định bởi pH của quá trình lên men.
Tập 1 Số 4 - Trang 393-412 - 1959
A new press for the disruption of micro‐organisms and other cells Abstract A new press (the X‐press) has been developed for the disintegration of cells in the frozen state (mostly at −25°C). By forcing the frozen cells contained in a cylinder through a hole much smaller than the diameter of the cylinder but much larger than the size of the cells, a satisfactory disintegration can be obtained. By forcing the cells through the hole repeatedly rather than once, a higher degree of disintegration can be achieved. By making the receiver identical to the charge chamber, repeated operations are possible without uncoupling the press. The disintegrated material is very easily recovered—it is simply taken out of the press in the form of a cylinder containing the frozen, disintegrated material which is then easily homogenized. This principle has been found satisfactory for the disintegration of a large number of cells, viz. bacteria, yeasts, moulds, plant and animal cells and, with regard to biochemical questions, it has been found to be superior to existing methods which do not treat the bacteria in the frozen state. The mechanism of the disintegrating action is discussed.
Tập 2 Số 4 - Trang 453-479 - 1960
Fermentation process kinetics Abstract Information on fermentation process kinetics is potentially valuable for the improvement of batch process performance; it is essential for continuous process design. An empirical examination of rate patterns in various fermentations discloses three basic types: (1) ‘growth associated’ products arising directly from the energy metabolism of carbohydrates supplied, (2) indirect products of carbohydrate metabolism and (3) products apparently unrelated to carbohydrate oxidation. Effects of operating variables on the primary kinetic processes, growth, sugar utilization and antibiotic formation, in the penicillin process, illustrate the special nature of this type.
Tập 1 Số 4 - Trang 413-429 - 1959
The separation of flour into fractions of different protein contents by means of air classification Abstract Fractions of markedly different protein contents may be obtained by air‐classifying flour (in the sub‐sieve range) at cut sizes of about 17 and 35 μ respectively. Of these fractions, the fine, 1 (of high protein content), contains fragments of interstitial endosperm protein and small starch granules; the intermediate, 2 (low protein), mainly large starch granules; the coarse, 3, fragments of endosperm cells. The yields and protein contents of the fractions vary with different wheats; the yields of 1 and 2 may be greatly increased through suitably grinding the flour after milling. In general, 1 may be used for raising the protein content of flours deficient in protein to a level suitable for bread‐making. The amount of 1 required depends on its protein contents and on whether it came from a hard or soft wheat, the hard wheat fraction having better bread‐making qualities. The resulting variation in the proportion of 1 required in the blend causes variation in the proportion of other particulate materials introduced with 1, in which they have become concentrated during the air classification. These include diastatically active agents and finely divided discolouring matter; the level of the former reached in the blend greatly affects its bread‐making value. Pre‐grinding of the flour may be helpful in this respect. When chlorinated, 2 is potentially useful for making light‐structured cakes, but hard English wheats have mainly given less satisfactory results than soft. Under certain conditions, 3, with or without 2, may be better for biscuit‐making than the parent flour.
Tập 1 Số 1 - Trang 77-98 - 1959