• 한국토양비료학회지
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• 제11권3호
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• pp.161-174
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• 1979

A review was made on the effect of organic matter application on the chemical characteristics of soils such as pH, solubilities of minerals, and cation exchange capacity mainly at flooded rice soils. The review can be summarized as follows: 1. Application of organic material such as rice straw and compost in flooded rice soil leads to a temporary lowering of soil pH at the earlier stage of soil reduction, due to the production of various organic acids and carbonic acid. This temporary lowered pH is replaced with the production of alkaline substances such as ammonia as the reduction of soil proceeds. 2. Incorporation of organic materials intensifies the ferrous iron, dissolving various minerals, virtually to the increase in electrical conductivity of soils. 3. Organic materials also play an important role in dissolving soil minerals through the production of various chelating agents. 4. Application of soil organic matter significantly increases cation exchange capacity of soils. 5. Continuous application of rice straw or compost leads to the increase in soil organic matter content to some extent, up to the level of equilibrium. In soils low in organic matter the equilibrium level is attained with five years continuous application of compost. 6. The manner of chemical fertilizer application influences the accumulation of organic matter applied in soils. Low levels of fertilization lowers the accumulation while high levels of fertilization accerelates the accumulation.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.121-124
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• 2000

본 연구의 목적은 식품부산물로부터 유기산 생산 및 분리 농축에 있다. 회분식 발효를 실시하여 균주의 최적 발효조건을 구하여 세포 재순환식 연속 발효공정에 적용한 결과, CSL의 최적 함량은 2.5%로 나타났으며 수율과 생산성은 각각 0.80g total acid/g glucose, 0.26g total acid/L/h로 향상 되었다. 세포 재순환식 연속발효 결과, 최대 유기산 생산성은 희석률 0.2/h에서 3.32g organic acid/L/h로 회분식 발효와 비교해 볼 때 최대 생산성으로는 13배, 세포량으로는 22배 증가한 것으로 나타났다. 또한, 최적 추출시스템은 30%w/w TOA/MIBK로 나타났으며, 발효액내의 유기산을 약 90%까지 분리 및 농축할 수 있음을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제12권2호
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• pp.273-278
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• 2002

Two-step fed-batch fermentations were carried out to overproduce Bacillus licheniformis maltogenic amylase (BLMA) in recombinant Escherichia coli. The first step was to increase the cell mass by controlling the feeding of a glucose solution, while the second step was designed to improve the amylase expression efficiency by supplementing organic nitrogen sources. The linear gradient feeding method was successfully adopted to maintain the glucose concentration below 0.2 g/l during the fed-batch mode, as effectively minimizing acetic acid formation. When the dissolved oxygen (DO) level became limiting, an accumulation of acetic acid and drastic decrease in specific BLMA productivity were observed. Glucose and organic nitrogen sources consisting of yeast extract and casein hydrolysate were simultaneously supplied in the pH-stat mode to further increase the specific BLMA expression efficiency. An organic nitrogen source consisting of 200 g/1 yeast extract and 100 g/1 casein hydrolysate was found to be the best among the various combinations tested. The feeding of an organic nitrogen source in the second-step fed-batch period was highly beneficial in enhancing the BLMA production. The optimized two-step fed-batch culture resulted in 78 g/l maximum dry cell mass and 443 U/ml maximum BLMA activity, corresponding to 1.5-fold increase in the dry cell mass and 3.7-fold enhancement in BLMA production, compared with the simple fed-batch fermentation.

• 한국식생활문화학회지
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• 제12권1호
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• pp.53-61
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• 1997

This study was carried out in order to investigate general characteristics, sugars and organic acids contents of Korean traditional soy sauce, and to find out possibility of high quality soy sauce production in a short period through high concentration soy sauce making. In this study, we prepared three different types of soy sauce, low concentration soy sauce (Chungjang), high concentration soy sauce and Kyupjang, high quality traditional Korean soy sauce. pH of soy sauce were $4.46{\sim}4.90$ and did not show difference among three samples. Titratable acidity, buffering power and total free acid content were the highest value in Kyupjang. Kyupjang showed the highest contents of salt and pure extract. As the ripening period increased, the salt content increased in Chungjang samples, but decreased in Kyupjang. Reducing sugar contents of Kyupjang, high concentration soy sauce and low concentration soy sauce were 1.13%, 0.76% and 0.53%, respectively. Free sugar in soy sauce were analyzed maltose, glucose, galactose and fructose. Total free sugar content was highest in high concentration soy sauce, however, contents of glucose and fructose were higher in Kyupjang than in Chungjang samples. Galactose was the main free sugar in Chungjang, but glucose was in Kyupjang. Among identified volatile organic acid, acetic acid was present in the highest concentration, and volatile organic acid content was highest in the high concentration soy sauce at 150 days. 20 nonvolatile organic acids were detected in Korean traditional soy sauce. Succinic acid, lactic acid and 2,5-pyridine dicarboxylic acid were the main nonvolatile organic acid in soy sauce.

• 한국균학회지
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• 제47권3호
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• pp.233-240
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• 2019

잎새버섯 안정생산을 위하여 배지의 pH를 적정하게 조절할 수 있는 방법을 개발하고자 유기산을 이용한 pH 조절 및 적정 첨가농도를 구명하기 위하여 수행하였다. 혼합배지에 4종의 유기산(구연산, 호박산, 사과산, 주석산)를 5수준(0.5, 1, 1.5, 2, 2.5, 3%)으로 처리하여 균사생장정도를 측정한 결과 유기산 0.5% 수준에서 균사생장이 빨랐으며, 그 중에서도 호박산이 가장 우수하였다. 유기산의 첨가농도가 높을수록 혼합배지의 pH는 낮아지는 경향으로 배양기간 경과에 따라 대조구의 pH는 서서히 낮아지는 경향을 보인 반면 유기산 처리구는 유지되는 경향이었다. 발이율은 0.5%의 농도에서 호박산이 95%, 구연산 92.5%, 사과산과 주석산 80%로 대조구의 60%보다 우수하였다. 그러나 유기산의 농도가 1% 이상에서는 발이가 지연되거나 억제되는 경향을 보여주었다. 배양기간은 유기산 0.5% 처리구가 30~34일로 대조구의 35일보다 빠른 것으로 나타났으며, 전체 재배기간은 0.5% 호박산이 52일, 0.5%의 구연산과 사과산이 54일, 0.5%의 주석산이 52일로 대조구의 59일보다 빠른 것으로 나타났다. 병당 수량성은 0.5%의 호박산과 구연산 첨가 시 각각 121 g, 107 g으로 가장 우수하였고 대조구의 87.5 g에 비해 21~37% 증수되었다.

• 환경위생공학
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• 제16권1호
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• pp.108-116
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• 2001

It is difficult to task to achieve high biological nutrient removal from municipal wastewater because of low organic content. Volatile fatty acids(VFAs) produced from acid fermentation of food wastes can be utilized as external carbon sources for the biological nutrient process. Significant reduction and stabilization of the food wastes can also be obtained from the acid fermentation. The objective of this study is to evaluate characteristics of acid fermentation of the food wastes. Results obtained from the batch experiment of various organic wastes showed that the food wastes had high potential to be used as an external carbon source because of the largest production of the VFAs with low nitrogen and phosphorus content. The fish waste was found to be the next possible organic waste, while the others such as radish cabbage and molasses waste showed high VFAs consumption potential as a results of high nitrogen and phosphorus content. alkaline hydrolysis of the food waste was carried out using NaOH prior to the acid fermentation. As the alkali addition increased, solubilization of the organics as well as TSS reduction increased. However, fraction of soluble COD to total COD became stable after a sharp increase. Alkali addition greater than 0.5g NaOH per g TS resulted in significant increase in pH.

• Environmental Engineering Research
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• 제19권4호
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• pp.355-361
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• 2014

The wastewater treatment with a two-phase expanded granular sludge bed (EGSB) system for anaerobic degradation of acetate, benzoate, terephtalate and p-toluate from purified terephtalic acid (PTA) production was studied. The feasibility and effectiveness of the system was evaluated in terms of organic oxidation by chemical oxygen demand (COD), gas production, bacterial adaptability and stability in the granular sludge. Average removal efficiencies 93.5% and 72.7% were achieved in the EGSB reactors under volumetric loading rates of $1.0-15kg-COD/m^3/day$ and terephtalate and p-toluate of 351-526 mg/L, respectively. Gas production reached total methane production rate of 0.30 L/g-COD under these conditions in the sequential EGSB reactor system. Higher strength influent COD concentration above 4.8 g-COD/L related to field conditions was fed to observe the disturbance of the EGSB reactors.

• 유기물자원화
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• 제14권1호
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• pp.131-138
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• 2006

본 연구는 혐기성 발효를 이용한 수소생산과정에서 pH를 일정하게 유지한 상태에서 안정적인 수소를 생산하기 위한 최적 pH를 찾고자 하였다. 실험결과 pH 6이었을 때 최적의 조건이었으며 이때 수소생산량은 1175.87 mL/L 이고, 이론적 수소 전환율은 22.51 %였다. pH 5는 901.77 mL/L의 수소가 발생되었으며, 수소 전환율은 17.48 %, pH 7은 454.26 mL/L의 수소생산량과 8.74 %의 수소 전환율을 나타내었다. 그리고 pH 7과 8에서는 각각 452.08 mL/L와 82.25 mL/L의 저조한 수소 생산량을 나타내었다. 자당의 혐기성 발효를 통한 유기산 생성에 있어서 pH가 7과 8에서는 propionate가 주로 관찰되었으나 pH가 5와 6인 영역 에서는 butyrate의 생성이 두드러지는 결과가 나타났다.

• Applied Biological Chemistry
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• 제41권5호
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• pp.395-398
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• 1998

생약에서 충치균에 대한 항균성 물질을 개발하기 위하여 수종의 야생생약을 수집하여 항균활성을 측정해 보았다. 그 중에서 충치균에 강한 항균활성을 나타낸 두송실(Juniperus rigida S. et Z.)을 methanol로서 추출하고 극성이 다른 수종의 용매로서 분획하여, 충치균에 대한 항균활성과 유기산의 생성억제효과를 측정해 본 결과, n-hexane, chloroform 분획에서 활성이 나타났다. 충치균에 의하여 생성된 유기산은 주로 lactic acid와 citric acid로 전체의 $80{\sim}90%$를 차지하였는데 두송실의 methanol추출물과 n-hexane분획물을 1 mg/ml 처리한 시험군에서 각각 89.3, 90.8%의 유기산 생성 억제효과를 나타내었다.

• 한국조리학회지
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• 제13권1호
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• pp.55-61
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• 2007

L. acidophilus KCCM 32820과 P. freudenreichii KCCM 31227의 성장곡선 및 5%와 10% 유청 배지를 고압증기멸균 및 저온살균하여 L. acidophilus KCCM 32820과 P. freudenreichii KCCM 31227을 혼합배양시 생성되는 propionic acid와 acetic acid 양을 측정하였다. L. acidophilus KCCM 32820의 대수기는 $6\sim21$시간, P. freudenreichii KCCM 31227의 대수기는 $36\sim108$시간으로 나타났다. 혼합배양시 propionic acid의 생성량은 5% 유청 배지보다는 10% 유청 배지에서, 고압증기 멸균보다는 저온살균에서 많은 양이 생성되었다. Propionic acid의 최대 생산량은 10% 유청 배지를 저온살균하였을 때 배양 120시간에 7.88 mg/mL이었다. Acetic acid도 5%보다는 10% 유청 배지에서 높은 생성량을 나타냈고 그 생성량은 배양시간이 경과함에 따라 propionic acid 생성량의 $2:1\sim3:1$이었다.