• Microbiology and Biotechnology Letters
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• v.28 no.6
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• pp.349-354
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• 2000

Culture conditions and nitrogen sources were optimized for production of erythritol, a natural sweetener, by Candida magnoliae M26. The optimal culture conditions were found to be culture temperature of $28^{\circ}C$, initial pH of 7, aeration of 1 vvm and agitation speed of 500 rpm in a 2.5 1 jar-fermentor. Glucose was chosen as the best carbon cource bsed on cell growth and erythritol productivity. Kight steep water(LSW) and corn steep liquor (CSL) which are by-products in starch processing from corn were tested as a nitrogen source substitute for yeast extract. The use of either LSW or CSL did not change the fermentation performance. The experimental results using LSW and CSL showed 1.5 times higher in cell growth and almost the same value in erythritol productivity com-pared with the control fermentation using yeast extract as a nitrogen source. These results suggested that either LSW of CSL could be used as a nitrogen source in a large-scale fermentation for erythritol production.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.99-104
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• 1990

The effects of concentrations of sulfur dioxide (0.16-0.20%) and steeping times (25-50hr) at $52^{\circ}C$ on the changes in pH of steep water and weight and volume of corn and starch properties were investigated. The pH of steep water increased and remained constant after steeping time of 20 hours. The degree of weight or volume gain decreased as the concentration of sulfur dioxide increased. The protein content of starch increased as the concentration of sulfur dioxide increased. Water·binding capacity of starch showed the highest value at the steeping time of 35 hours. Swell ins power and solubility decreased as cocentration of sulfur dioxide and steeping time increased. The initial pasting temperature and peak viscosity were increased and decreased, respectively, as the concentration of sulfur dioxide increased. At the same concentration of sulfur dioxide, the peak viscosity was increased and then decreased. Viscosity of starch in sodium hydroxide solution tended to decrease as the concentration of sulfur dioxide and sleeping time increased. The gel volume of starch in 3M KSCN solution was not affected by concentration of sulfur dioxide and steeping time.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1493-1501
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• 2018

Wastewater from cider factories (losses during transfers, products discarded due to quality policies, and products returned from the market) exhibits a Chemical Oxygen Demand greater than $170,000mg\;O_2/l$, mainly due to the ethanol content and carbohydrates that are added to obtain the finished product. These effluents can represent up to 10% of the volume of cider produced, and they must be treated to meet environmental regulations. In this work, a process was developed, based on alcoholic fermentation of the available carbohydrates present in ciders. The impact of inhibitors at different pH, size and reuse of inoculums and different nutrient supplementation on the ethanol yield were evaluated. The use of a 0.5 g/l yeast inoculum and corn steep water as the nutrient source allowed for depletion of the sugars in less than 48 h, which increased the content of ethanol to more than 70 g/l.

• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.739-745
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• 2011

During the production of grape wine, the formation of thick leathery pellicle/bacterial cellulose (BC) at the airliquid interface was due to the bacterium, which was isolated and identified as Gluconacetobacter hansenii UAC09. Cultural conditions for bacterial cellulose production from G. hansenii UAC09 were optimized by central composite rotatable experimental design. To economize the BC production, coffee cherry husk (CCH) extract and corn steep liquor (CSL) were used as less expensive sources of carbon and nitrogen, respectively. CCH and CSL are byproducts from the coffee processing and starch processing industry, respectively. The interactions between pH (4.5-8.5), CSL (2-10%), alcohol (0.5-2%), acetic acid (0.5-2%), and water dilution rate to CCH ratio (1:1 to 1:5) were studied using response surface methodology. The optimum conditions for maximum BC production were pH (6.64), CSL (10%), alcohol (0.5%), acetic acid (1.13%), and water to CCH ratio (1:1). After 2 weeks of fermentation, the amount of BC produced was 6.24 g/l. This yield was comparable to the predicted value of 6.09 g/l. This is the first report on the optimization of the fermentation medium by RSM using CCH extract as the carbon source for BC production by G. hansenii UAC09.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.647-651
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• 1995

A tylosin-hyperproductive mutant of S. fradiae MNU20 was isolated among 3500 strains obtaincd from either MNNG- or UV-treated Streptomyces fradiae NRRL2702. The composition of optimal medium for tylosin production was formulated as followed as: 4 g soluble starch, 1 g glucose, 1 g corn steep liquor, 7.5 ml soy bean oil, 0.2 g KH$_{2}$PO$_{4}$, 1 g Na$_{2}$S$_{2}$O$_{3}$$\cdot $5H$_{2}$O, 2 g CaCO$_{3}$, 2 g NaCl, 0.001 g CoCl$_{2}$$\cdot $6H$_{2}$O in 1 liter of distilled water. With the optimal medium, S. fradiae MNU20 was able to produce 159 mg tylosin (g biomass)$^{-1}$, indicating that tylosin productivity of Streptomyces fradiae NRRL2702 was increased 14 times higher by mutation. When the effect of valine, succinate, and natural zeolite on tylosin production was investigated by using the optimal medium, these substances essentially enhanced tylosin production and their addition time during culture period appeared to be critical for the increase of tylosin production.

• Journal of Microbiology and Biotechnology
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• v.20 no.4
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• pp.737-748
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• 2010

Glutaminase production in Zygosaccharomyces rouxii by solid-state fermentation (SSF) is detailed. Substrates screening showed best results with oatmeal (OM) and wheatbran (WB). Furthermore, a 1:1 combination of OM:WB gave 0.614 units/gds with artificial sea water as a moistening agent. Evaluation of additional carbon, nitrogen, amino acids, and minerals supplementation was done. A central composite design was employed to investigate the effects of four variables (viz., moisture content, glucose, corn steep liquor, and glutamine) on production. A 4-fold increase in enzyme production was obtained. Studies were undertaken to analyze the time-course model, the microbial growth, and nutrient utilization during SSF. A logistic equation ($R^2$=0.8973), describing the growth model of Z. rouxii, was obtained with maximum values of ${\mu}_m$ and $X_m$ at $0.326h^{-1}$ and 7.35% of dry matter weight loss, respectively. A goodfit model to describe utilization of total carbohydrate ($R^2$=0.9906) and nitrogen concentration ($R^2$=0.9869) with time was obtained. The model was used successfully to predict enzyme production ($R^2$=0.7950).

• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.123-133
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• 1972

Over 90 of lysine producing auxotrophs were obtained from Corynebacterium sp. S-27-12, Brevibacterium flavum ATCC 15168 and Micrococcus glutamicus ATCC 13032 by UV light, $Co^{60}$ irradiation and N-methyl-N'-nitro-N-nitrosoguanidine treatment. One of the mutant, Brev. flavum U46-N59, was identified as a leucine auxotroph and accumulated lysine during flask (500 ml) cultivation (180 strokes/min.) up to 21.6 mg per ml of broth at pH 7.5 and $28^{\circ}C$ after 4 days. The medium consisted of glucose, 100; urea, 10; corn steep liquor, 40; $KH_2PO_4,\;2;\;K_2HPO_4,\;0.5;\; MgSO_4.\;7H_2O,\;0.4;\;antifoam\;S-57,\;1g;\;Fe_2(SO_4)_3.XH-2O,\;10;\; MnCl_2,\;4H_2O,\;10mg;\;biotin,\;30;\;thiamine-HCl,\;100{\mu}g$in 1l of distilled water, and 40 U/ml of penicillin was added after 36 hrs fermentation.