Effect Of pH Control Research Articles

Growth of and production of γ-decalactone by Sporobolomyces odorus in jar fermentors as affected by pH, aeration and fed-batch technique

In jar fermentors, Sporobolomyces odorus grew rapidly and entered the stationary growth phase at approximately 72 h of cultivation. During the 192 h fermentation period, pH and DO concentration in the medium first decreased and then increased. A maximum yield of γ-decalactone of 54.6 mg/ l was noted after 120 h of cultivation. Studies on the effects of pH control and aeration rate revealed that maintaining the pH of the medium at 4.0, 5.0, 6.0 or 7.0 neither affected the growth of S. odorus nor improved the yield of γ-decalactone, and that although a larger maximum final population was found in the culture with an aeration rate of 2 vvm, a greater yield of γ-decalactone was noted when aeration rate was maintained at 1.0 or 1.5 vvm. A significant increase in the maximum yield of γ-decalactone was noted in fed-batch culture of S. odorus. The maximum yield of γ-decalactone increased with the number of castor oil hydrolysate feedings. Fed-batch cultivation of S. odorus with additions of castor oil hydrolysate on the 3rd, 4th and 5th d of cultivation resulted in a maximum yield of 208 mg/ l γ-decalactone which was noted after 7 d of cultivation.

Effects Of pH Control On Composting Of Garbage

Composting experiments of garbage were conducted by using a laboratory scale reactor under well controlled experimental conditions and the effects of pH control were quantitatively analysed. In the pH controlled experiment, lime was added to prevent pH decreasing below 7, especially at the early stage of composting. The degradation rate of organic matter in the pH controlled experiment was faster than that without. Nitrogen loss was enhanced by the control of pH value, but the amount of promotion was relatively small. The pH dependency on the activity of microorganisms, which contribute to the composting rate, was investigated by using a liquid medium containing glucose and proteins as nutrients. The optimum pH for the growth rate and the degradation activity of proteins of the microorganisms was in the range of 7-8, while the decomposition of glucose proceeded rapidly at an early stage of composting in a pH range from 6 to 9.

Effects of pH Control On Composting of Garbage

Composting experiments of garbage were conducted by using a laboratory scale reactor under well controlled experimental conditions and the effects of pH control were quantitatively analysed. In the pH controlled experiment, lime was added to prevent pH decreasing below 7, especially at the early stage of composting. The degradation rate of organic matter in the pH controlled experiment was faster than that without. Nitrogen loss was enhanced by the control of pH value, but the amount of promotion was relatively small. The pH dependency on the activity of microorganisms, which contribute to the composting rate, was investigated by using a liquid medium containing glucose and proteins as nutrients. The optimum pH for the growth rate and the degradation activity of proteins of the microorganisms was in the range of 7-8, while the decomposition of glucose proceeded rapidly at an early stage of composting in a pH range from 6 to 9.

Effect of pH control on the growth and survival ofKluveromyces fragilis in cheese whey under aerobic condition

Many biological and chemical systems involve acid-base equilibria and thus depend critically on the pH of the solution. Small fluctuations of pH must be corrected by the addition of an acid or base to maintain the pH at the required optimum level during the fermentation process. The effect of pH control on the growth ofKluveromyces fragilis, used for the production of single-cell protein from cheese whey, was investigated. Maintaining the pH at 4.5 was found essential for the survival of the yeast. Without pH control, the pH of the medium continued to rise, resulting in the death and/or sporulation of the yeast cells. Diauxic growth was observed, caused by the growth of contaminant bacteria when the pH was not controlled.

Production of Leuconostoc oenos Biomass under pH Control

Leuconostoc oenos was grown on apple juice-based media. The effect of pH control on metabolism and biomass production was studied. Without pH control, L. oenos acidified the apple juice media to approximately pH 3.6. More than 75% of the malic acid was used under these conditions, but less than half of the carbohydrates was assimilated. Under pH control, biomass yields increased by 60%; most of the malic acid was used, but high levels of unfermented carbohydrates remained. The addition of tomato juice, vitamins, nucleotides, Mn, and malic acid did not permit further increases in the cell counts; however, malic acid did induce further acidification. Growth without pH control favored a more homofermentative metabolism. Biomass production was higher in filter-sterilized apple juice media compared with that in the autoclaved media.

Optimization of sucrose phosphorylase production by Leuconostoc mesenteroides

AbstractEnvironmental optimization of the Leuconostoc mesenteroides ATCC 12291 sucrose phosphorylase fermentation process was undertaken. The effects of pH control, fermentation temperature and medium composition on growth, culture viscosity, sucrose utilization pattern and dynamics of enzyme fermentation were studied. Optimized fermentations were run at controlled pH 7 at 32°C yielding high enzyme levels. Applications of sucrose phosphorylase are discussed.

Microbial production of abscisic acid with Cercospora rosicola. II. Effect of pH control and medium composition

Culture conditions for abscisic acid accumulation by Cercospora rosicola were tested. Additions of corn steep liquor and CaCO3 as pH controller to potato dextrose medium raised ABA accumulation to 300 ug/ml or more in 20 days; a medium comprising glucose, cornsteep liquor and minerals could replace potato dextrose.

Effect of pH control on dyeing of polyester materials with disperse dyes

AbstractDyeing of polyester materials with disperse dyes at a high temperature in the absence of carriers and at different ranges of dyebath pH was studied. It was found that the behaviour of the dye as well as the magnitude of dye uptake at different pH's are greatly affected by nature and position of the substituents of the dye. Substituents which from lyonium ions in acidic medium produce higher dye uptake in alkaline medium, and those which form lyate ions in alkaline medium bring about higher dye uptake in acidic medium. Substituents which are not able to form neither lyonium ions nor lyate ions yield practically the same dye uptake over a wide range of pH values.

Effect of pH control and increased O2 delivery on the course of hemorrhagic shock.

Manger, W. M. M.D.; Nahas, G. G. M.D.; Hassam, D. M.D.; Habif, D. V. M.D.; Papper, E. M. M.D. Author Information