Showing papers on "Sodium propionate published in 1992"

Enhanced β‐galactosidase production by high cell‐density culture of recombinant Bacillus subtilis with glucose concentration control

Abstract: Cell concentration, recombinant protein (beta-galactosidase) level, and the specific enzyme expression level were increased from 19 to 184 g/L, 18.3 to 129 U/mL, and 3.2 to 5.7 U/mg protein, respectively, in fed-batch culture of recombinant Bacillus subtilis when glucose concentration was controlled at 1 g/L as compared with those of conventional fed-batch culture. Glucose concentration of the culture broth was monitored by an automatic on-line glucose analyzer and controlled with a moving identification combined with optimal control (MICOC) strategy. When glucose concentrations were controlled at 10, 1, and 0.2 g/L, accumulated propionic acid concentrations and specific enzyme activities were 18.5, 4.4, and 0.6 g/L and 2.9, 5.7, and 7.1 U/mg protein, respectively. The addition of various concentrations of sodium propionate to the growth medium in batch cultures resulted in a drastic decrease in the growth rate with respect to propionate concentration. The propionic acid was shown to be responsible for cell growth inhibition and enzyme activity reduction in fed-batch culture.

Recovery of propionic and acetic acids from fermentation broth by electrodialysis

Abstract: Acetic and propionic acids can be produced by fermentation. In this process, acid recovery is important both for producing a concentrated product from the broth and for removing acid from the broth to reduce product inhibition during the fermentation. The purpose of this work was to characterize the performance of an electrodialysis unit for carrying out both tasks. Current efficiencies, water transport, and product concentrations were determined both for model solutions of the acids and for fermentation broths to determine the limiting factors in using this separation method. In addition, observations were made of fouling behavior of the membranes in this use. The highest concentrations of product were obtained by contacting with the most concentrated feed and doing so in the absence of competing ions. For the range studied here, a maximum concentration of 13.8% (w/v) sodium propionate was obtained. In the batch recycle mode, final concentrations in the concentrate were reduced, but acid recoveries were improved by the presence of other ions because the low-current shut-off was delayed. The use of electrodialysis for producing a concentrated acid product is not promising unless salt levels in the medium can be reduced and acid levels increased. However, electrodialysis can be used to maintain low acid levels in the fermentor during extractive fermentation.

Composition for extending the shelf life of processed meats

Abstract: A composition for inhibiting the growth of bacteria in raw or processed meat products having a pH between about 6.0 and 6.5 stored at above freezing temperatures using an inorganic propionate salt which extends the shelf life of the meat is described. The salt is preferably sodium propionate or calcium propionate and is used in an amount less than about 1% by weight and preferably between about 0.05 and 0.5 percent by weight of the meat such that no flavor is imparted to the meat. Preferred dried compositions containing a bacteriocin from Pediococcus acidilactici and a propionate salt are also described.

The preparation of 14C‐labeled FK‐506

Abstract: Utilizing sodium [1−14C]propionate as a precursor, [14C]FK-506, labeled at carbon atoms 10, 16, 18, 21a, 24, and 26, was produced by fermentative biosynthesis. Extractive isolation followed by chromatographic purification provided material of purity suitable for metabolism studies.

Elevated urinary excretion of orotic acid in sheep caused by intraruminal infusion of sodium propionate

Abstract: 1. The effect of sodium propionate on urinary excretion of orotic acid was investigated. 2. Solutions containing sodium propionate or NaCl, 750 mM/day each, were continuously infused into the rumen for 10 days. 3. During NaCl infusion, an urinary orotic acid excretion of 290 +/- 80 micrograms/day was noted. The intraruminal infusion of sodium propionate raised the concentration of propionic acid in the rumen fluid from 14.0 +/- 0.9 to 26.9 +/- 1.9 mM. 4. During this experimental period the excretion of orotic acid via urine significantly increased to 492 +/- 30 micrograms/day. Parameters of nitrogen balance were not altered by propionate. 5. It is suggested that the site of propionate action in intact sheep is in the pyrimidine synthesis pathway.

Viscosities and densities of alkali propionates in propionic acid + methanol mixtures

Abstract: Viscosity and density data for propionates of lithium, sodium and potassium have been measured at 308.15K in propionic acid + methanol (PA+MeOH) mixtures containing 0, 5, 15, 25% (w/w) CH 3 OH. The experimental results of viscosity have been analysed using the Jones-Dole equation. The activation parameters of viscous flow have been obtained to throw light on the mechanism of the viscous flow. The apparent molar volume of these electrolytes at different concentrations have been estimated and indicate that these behave as structure makers/promoters

Method and composition for preserving edible meat

Abstract: PURPOSE: To suppress the growth of deterioration bacteria in meat of about pH 7 at a chilling temp. without adversely affecting the taste of the meat. CONSTITUTION: An inorg. propionate such as sodium propionate or potassium propionate is added to meat by <=1wt.% and bacteriocin derived from Pediococcus acidilactici is also added.