• KSBB Journal
• /
• v.19 no.3
• /
• pp.226-230
• /
• 2004

Fermentation characteristics of D-xylose into xylitol by Candida mogii ATCC 18364, a potential xylitol producer from rice straw hemicellulose hydrolyzates, were investigated. The influences of the most important operational variables on xylitol production were examined. The best results in xylitol production were obtained in shake-flask fermentations when 3.0 g/L initial cell concentration of 12 hr-old cells grown in D-glucose containing medium were used as inoculum. The oxygen availability is a critical factor in xylose fermentation, therefore, xylose conversion into xylitol was investigated in a 2-L fermenter at different stirring rates. Maximum xylitol production was obtained with an aeration rate of 1 vvm at a stirring rate of 200 rpm.

• Korean Journal of Food Science and Technology
• /
• v.34 no.1
• /
• pp.30-36
• /
• 2002

To use overproduction muskmelon effectively, muskmelon vinegar was prepared by two stage fermentations of alcohol and acetic acid. In the alcohol fermentation using muskmelon, alcohol content showed maximum value (7.47%) in $17.83^{\circ}Brix$ of initial sugar concentration and 82.65 h of fermentation time. Acetic acid content in alcohol fermentation revealed minimum value (0.46%) in $12.17^{\circ}Brix$ of initial sugar concentration and 60.56 h of fermentation time. The fermentation conditions for minimum residual sugar were $10.02^{\circ}Brix$ of initial sugar concentration and 105.61 h of fermentation time. The optimum conditions predicted for each corresponding physical properties of acetic acid fermentation were 200 rpm (agitation rate), 250 h (fermentation time) in acetic content and 200 rpm, 150 h in residual alcohol content.

• KSBB Journal
• /
• v.16 no.4
• /
• pp.403-408
• /
• 2001

Distillation condensate generated from downstream processing of microbial alcohol fermentation imposes a serious burden to biological wastewater treatment or anaerobic digestion due to its high contents of SS (suspended solids) and TN (total nitrogen), A pilot scale microfiltration of the stillage condensate with a stainless steel SCEPTER membrane of 0.1 ${\mu}$m pore size was carried out to remove SS which was mostly composed of microbial cell residue. A stable permeate flux was achieved when the decanter effluent containing 0.7% of SS was filtered under the conditions of X10 VCR (volume concentration ratio), 2.5 bar of TMP (transmembrane pressure), and 60$^{\circ}C$. When stillage condensate with 2.6% SS was treated directly with microfiltration, VCR below X3 was recommended for a long duration of filtration. The permeate and retentate obtained from microfiltration were recycled to make-up medium of fermentation. Adding permeate or retentate up to 30% of fermentation volume showed no distinguished undesirable influence during the course of alcohol fermentation. Although only slight improvements in the final amount of CO$_2$ evolution and alcohol content were observed, fermentation rate increased so that the required time to reach 450 L/ton of CO$_2$ evolution was shortened to 72% of that with normal media.

• KSBB Journal
• /
• v.8 no.5
• /
• pp.446-451
• /
• 1993

In ethanol fermentation, by-products such as glycerol, acetic acid and lactic acid are produced along with ethanol. The effects of culture conditions on cell growth ethanol production and by-products biosynthesis were investigated in ethanol fermentation using S. cerevisiae. With increasing aeration rate or yeast extract concentration, ethanol and by-products biosynthesis decreased while final cell mass increased. With increasing glucose concentration or decreasing temperature, final cell mass, ethanol and by-products concentrations all increased. The optimal pH for the cell growth, ethanol and by-products productions was found to be pH 4.5. By-products biosynthesis was found, in general, to proceed with the ethanol biosynthesis. The results can be applied for the optimization of ethanol fermentation and for the recovery and purification of ethanol from the culture broth.

• Microbiology and Biotechnology Letters
• /
• v.9 no.4
• /
• pp.191-196
• /
• 1981

In order to utilize the Koryangju distillers' grain for the acetic acid fermentation, the extracting methods and effects of the extracts on the fermentations were investigated. The result obtained are as follows. 1. Cold extracting method by which the distillers grain is extracted with 3 times of water for 60 hours at room temperature was better than hot extracting method in terms of the fermentation rate and the quality of vinegar product. 2. Optimum conditions and some results of surface fermentation based on the medium added by the extracts are as follows, optimum amount of the extracts to be added to the medium is 20-30% of total media; acetic acid production rate at log phase was 0.16g/100$m\ell$, hr.; recovery was 91.17%; and the time of 40 hours was required for the completion of fermentation. 3. Organoleptic quality of the vinegar which is produced by adding the extracts was superior to two commercial products examined.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.26 no.2
• /
• pp.65-73
• /
• 2018

This study was carried out for 20 days in a bio-drying batch reactor under the blowing conditions of 0.75, 1.00, 1.25, and $1.50L/min{\cdot}kg$ in order to optimize the operating conditions for the bio-drying of food wastes. The decomposition rate of organic matter during the bio-drying operation period was analyzed using modified Gompertz model. The maximum organic degradation (P) was 2.31, 2.52, 2.27 and 1.88 kg at air flow rates of 0.75, 1.00, 1.25 and $1.50L/min{\cdot}kg$, and the maximum organic degradation rate was 0.33, 0.45, 0.28, and 0.18 kg/day at 1.00, 1.25 and $1.50L/min{\cdot}kg$, respectively, showing excellent organic decomposition efficiency at a air flow rate of $1.00L/min{\cdot}kg$. The lag growth phase time (${\lambda}$) of the bio-drying reactor was 2.10, 1.48, 1.15, and 1.06 days at 0.75, 1.00, 1.25 and $1.50L/min{\cdot}kg$, respectively. The water removal rate in the operation of bio-drying reactor of food waste increased with the increase of air flow rate from the early stage of bio-drying to the middle stage, and the highest water removal rate was observed at the air flow rate of $1.00L/min{\cdot}kg$ at the end of bio-drying. The optimum air flow rate condition of bio-drying reactor was $1.00L/min{\cdot}kg$.

• Korean Journal of Food Science and Technology
• /
• v.34 no.3
• /
• pp.413-418
• /
• 2002

The dough was frozen either before or after fermentation at the five different freezing and storage conditions. Although fermentation before freezing was effective for rapid freezing, it reduced bread volume of the dough frozen at both air freezer and liquid immersion freezer. Freezing at the air freezer set to $-70^{\circ}C$ took more time for freezing and resulted in lower bread volume than freezing at the immersion freezer set to $-20^{\circ}C$. Therefore, the freezing in the liquid immersion freezer was more effective to reduce the freezing time and increase the bread volume. At the liquid immersion freezer, the higher temperature was more effective than lower temperature. The doughs frozen in a liquid immersion freezer set to $-10^{\circ}C$ and fermented after de-frosting produced higher bread volume than control unfrozen dough. And also there was no significant difference in bread volume between the control unfrozen dough and the dough frozen in a liquid immersion freezer set to $-10^{\circ}C$, fermented before freezing and re-fermented after defrosting. The longer proof time and greater loaf volume obtained for the dough frozen and stored at the air freezer set to $-70^{\circ}C$. Therefore the optimum process for freezing the dough was freezing immediately after mixing, storing at $-10^{\circ}C$ in a liquid immersion freezer and fermented after defrosting.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.7
• /
• pp.1064-1071
• /
• 2015

Viscous fermented red ginseng extracts were dried and coated using a fluidized bed coater to increase convenience and consumer acceptance. The methods for making spherical granules of fermented red ginseng extracts with increasing convenience were established by using indigestible dextrin. Spherical granules of fermented red ginseng extracts with increasing convenience were made by mixing indigestible dextrin at 40% (40% IDD), 50% (50% IDD), and 60% (60% IDD) versus the soluble solid content of fermented red ginseng extracts. Spherical granules of fermented red ginseng extracts showed less angle of repose than powder of fermented red ginseng extracts. This means that spherical granules of fermented red ginseng extracts had good fluency with increased convenience. The more indigestible dextrin showed higher yields. Although 50% IDD showed less yield than 60% IDD, 50% IDD was the best mixing ratio for making spherical granules of fermented red ginseng extracts, as fermented red ginseng extracts is known as a healthy food. The optimized operation conditions of the fluidized bed coater for making 50% IDD were feeding rate 0.54 mL/min, atomization air pressure 2.15 bar, and product temperature $83.03^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.8
• /
• pp.1289-1295
• /
• 2014

The aim of this study was to select the most suitable starter cultures for production of fermented sausages. A total of 27 strains isolated from Korean fermented foods and natural substances were characterized with respect to their physicochemical properties in a fluid (submerged) model system modified according to the special conditions of fermented sausages. Three of these strains were pre-selected for testing as potential cultures based on their ability to grow fast and initiate rapid acidification. The selected strains were identified by API and partial sequence analysis of 16S rRNA. The results exhibited sequence similarity to known sequences of Staphylococcus warneri, Staphylococcus epidermidis and Lactobacillus plantarum. Among them, relatively good growth properties and nitrite reduction activities were detected for S. epidermidis and L. plantarum and low pH values and high total acidities were observed in the model system fermented with these isolates compared with reference strains.

• Proceedings of the Korean Institute of Resources Recycling Conference
• /
• 2001.05a
• /
• pp.507-510
• /
• 2001

본 연구에서는 음식물 찌꺼기를 원료로 생균 발효사료를 생산하기 위해 단시간 호기적 발효에 필요한 고온성 균주를 개발하고자 하였다. 폐기물 처리장이나 경작연수가 10년 이상 경과된 농경지 야산의 토양 등 유기물질이 많은 장소에서 채취한 토양은 종균원으로 이용하였다. 1차 Screening을 통해 재배지(B group), 폐기물 처리장(F group), 야산(W group)에서 채취한 토양과 시판 발효용 종균제로부터 고온성 세균들을 분리한 뒤 고온.호기적 속성 발 효에 적합한 균주를 가려내기 위해 발효실험을 통한 2차 screening을 실시하였다. 그 결과, 재배지 토양으로부터 Bl, B2, B3, B4, B6, 폐기물 처리장으로부터 Fl, F2, 야산으로부터 W1, W3, W4 등의 세균이 선발되었다. 이들 중 특히 B6는 발효개시 4시간만에 생균수가 1.3$\times$$10^{9}$m1에 이르러 높은 중식속도를 나타냈고, 8시간만에 최고치인 7.5$\times$$10^{9}$ml까지 증가하여 호기적 고온성 속성 발효에 적합한 균주로 사료되었다.