Organic Acid Production by Propionibacterium shermanii: Effect of pH, Temperature and Vitamin-Nitrogen Source

1997 ◽  
Vol 52 (3-4) ◽  
pp. 193-196 ◽  
Author(s):  
A. Quesada-Chanto ◽  
A . G. Schroeder ◽  
A. C. Schmid-Meyer ◽  
J. A. López ◽  
M. M. Silveira ◽  
...  

Abstract Production of propionic acid by Propionibacterium shermanii CDB 10014 was enhanced by a pH value of 6.5 and by temperatures in the range 35-37 °C. Depending on the type of yeast extract, succinic acid can be produced in higher proportions, with decreasing propionic acid yields. With respect to propionic acid production, Difco yeast extract has shown the best results when yeast extract preparations from other different suppliers were compared. To replace yeast extract by a cheaper vitamin-nitrogen source, corn-steep liquor was tested. A complete depletion of glucose was achieved, yielding a final propionic acid concentration of over 35 g/l. These results are even better than those obtained with Difco yeast extract and suggest the possibility of an economical process based on corn-steep liquor.

1946 ◽  
Vol 24f (1) ◽  
pp. 29-38 ◽  
Author(s):  
Sybil B. Fratkin ◽  
G. A. Adams

Wheat starch is a poor medium for fermentation by Aerobacillus polymyxa. The solubles recovered from the separation of starch and gluten in patent flour enhance the fermentation but not as effectively as the similar fraction from whole wheat flour. Addition of supplements is necessary for a satisfactory yield of products in a reasonable length of time. Wheat gluten has no stimulatory effect but bran and shorts are both effective, the latter being slightly superior. An 8% starch medium fortified with the solubles from whole wheat required a 2.5% supplement of shorts to bring fermentation by A. polymyxa to 90% completeness in 72 hr.Of the various supplements tested, a 1% addition of malt sprouts proved to be the most effective, fermentation being 90% complete in 72 hr. Shorts, bran, Cerogras (dehydrated young oats), alfalfa, soya beans, yeast extract, and corn-steep liquor follow in order of decreasing effectiveness.The solubles from whole wheat when ashed have no beneficial effects on the fermentation of starch by A. polymyxa.


Author(s):  
Ivo Vyskočil ◽  
Petr Doležal ◽  
Jan Doležal ◽  
Václav Pyrochta ◽  
Libor Kalhotka

The aim of the work was to evaluate the effect of addition of humidity absorbent (malt sprouts) and chemical conservation additive on fermentation process quality of brewer grains’ silage. Chemical conservation additive was based on formic acid, propionic acid, benzoic acid and ammonium formate content. In a model experiment the fresh brewer grains were used. A dry matter (DM) content of brewer grains was 187.4 g / kg. Six treatments with three repetitions per treatment were prepared. The treatments A1, A2 and A3 were not supplied by humidity absorbent. Treatment A1 was a control treatment without any additive. The treatments A2 and A3 were supplied by chemical conservation additive in a dose of 3 L per tonne and 6 L per tonne, respectively. The treatments B1, B2 and B3 were supplied by malt sprouts to reach DM content of conserved matter on level 320–350 g / kg. Moreover the treatments B2 and B3 were supplied by chemical additive with its dose 3 and 6 L per tonne. Model silages were evaluated after 8 months of conservation at average laboratory temperature 26–28  °C, from each treatment were the final laboratory samples taken and analyzed. During conservation of treatments B1, B2 and B3 were no drain recognized. From A1 treatment drained 1300 ml of waste fluid that is 145 L per tonne of conserved matter. That was significant (P < 0.01) the malt sprouts addition support the lactic acid production and eliminate acetic acid production. There was no propionic acid or butyric acid detected in silages with malt sprouts event in these silages were analyzed higher (P < 0.01) concentration of ammoniac. Chemical additive supplementation improved (P < 0.01) the pH value and water leach acidity. The results show the malt sprout addition eliminates waste fluid drain and improves fermentation process. The higher concentration of chemical additive (6 l / t) inhibited the fermentation process in our model experiment.


1956 ◽  
Vol 2 (1) ◽  
pp. 28-38 ◽  
Author(s):  
F. J. Simpson

A number of carbohydrates and nitrogenous adjuncts were tested for their effect on the constitutive and adaptive pentosanases produced by Bacillus stibtilis and B. pumilus respectively in a medium containing biotin, ammonium phosphate, and other mineral salts. B. subtilis produced more enzyme with sulphite liquor than with any of the other carbohydrate sources tested. Next, in decreasing order of merit, were wheat bran, maltose, ribose, beet molasses, oat hulls, and pectin. Of the nitrogenous adjuncts tested, corn steep liquor, soybean meal, gelatin, gelysate, and ammonium lactate doubled the yield of enzyme whereas yeast extract, peptone, urea, and others were less effective. For B. pumilus the better carbohydrate sources, in decreasing order of merit, were wheat bran, water soluble pentosan of wheat flour, xylan, straw holo-cellulose, wheat straw, and sulphite liquor. Of the nitrogen sources, corn steep liquor was outstanding while casein, casitone, phytone, yeast extract, distillers' dried solubles, and soybean meal followed in decreasing order. A medium containing 6% wheat bran (20 mesh), 1% corn steep liquor neutralized with ammonia, 0.05% sodium chloride, and 0.05% calcium carbonate was devised for the production of pentosanase by B. pumilus. With this medium in shaken Erlenmeyer flasks, the enzyme was produced at a high rate between 12 and 40 hr.; thereafter the rate of production decreased. Maximum yields were obtained in 96 hr. A temperature of 26 °C. was more favorable for pentosanase production than higher temperatures.


1997 ◽  
Vol 52 (9-10) ◽  
pp. 705-708
Author(s):  
A. Quesada-Chanto ◽  
A. C. Schmid-Meyer ◽  
A. G. Schroeder ◽  
M. M. Silveira ◽  
M. F. Carvalho-Jonas ◽  
...  

Propionibacteria have been reported as being oxygen sensitive bacteria. Nevertheless, in this work, we intend to show that Propionibacterium shermanii CDB 10014 is able to grow even at high volumetric oxygen transfer coefficients (KLa). Similar final cell concentrations were achieved in experiments at different KLa values, with increasing cell yield from 0.08 g/g cells in anaerobic conditions to 0.22 g/g at KLa 61 h-1. The organic acid production pattern changes depending on the KLa. At KLa higher than 36 h-1, propionic acid was not produced and acetic acid was the main product. At KLa higher than 20h-1, lactic acid began to be produced. In further studies, no important differences in the growth yield were observed in the pH range 5.5-7.0, while the cell production was enhanced by tem peratures in the range 30-35 °C


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