The Optimum Dietary Essential Amino Acid Pattern for Male Taiwan Country Chicks

Wei, Hen-Wei,Kuo, Hsin-Mei,Chiu, Wen-Zan,Chen, Bao-Ji Asian Australasian Association of Animal Productio 2009 Animal Bioscience Vol.22 No.8

The objective of this study was to estimate the optimum dietary essential amino acid pattern for male Taiwan country chicks. A series of experiments was conducted with chicks, 14 d of age, for 2 wks. A basal synthetic diet was established using a dose response test for all essential amino acids referring to the broiler requirements recommended by NRC (1994). Twelve chicks were sacrificed at the beginning to provide initial body nitrogen data, and every group of six birds received the basal diet or a diet with a deficiency in a single essential amino acid in twenty one treatments by intubation according to their daily metabolic body weight (MBW). Deposited body nitrogen was determined using comparative slaughtering. According to the daily intake from the limiting amino acid per unit of MBW and the body nitrogen accretion rates for every two deficient groups with the same limiting amino acid but at different levels, a corresponding straight line was computed for each essential amino acid to intersect with a horizontal line made by the body nitrogen accretion rate of the control group. The x coordinate of the intersection represented the daily requirement for growth plus maintenance based on MBW corresponding to the essential amino acid. The amino acid ratios can be considered as the optimum pattern of dietary essential amino acids. The results, expressed with respect to lysine = 100, were arginine 105, methionine 81, histidine 34, tryptophan 18, leucine 103, phenylalanine 135, isoleucine 69, threonine 65 and valine 79. This pattern could be utilized to compute the dietary requirements (g/kg feed) for all essential amino acids by multiplying by the requirement of a single essential amino acid cited from the literature.

Comparison of Flocculation-Spectrophotometry and Streaming Current Detector Method to the Control of Flocculants for the Removal of Humic Acid

Kam Sang-Kyu,An Lee-Sun,Lee Min-Gyu The Korean Environmental Sciences Society 1997 Environmental sciences Vol.1 No.2

Flocculation-spectrophotometry and streaming current detector(SCD) method were investigated and compared in order to determine the optimum dosages of synthetic cationic polymers of different charge density and molecular mass for the removal of humic acid. The optimum dosage for each of the polymers was determined with the dosage at which the lowest absorbance of humic acid was shown for the former and was determined with the dosage required during charge neutralization of humic acid for the latter. It was in good agreement between both methods and there is a strong inverse correlation between the optimum dosage and charge density of the polymers, with highly charged polymer giving the lowest optimum dosage, pointing out the importance the charge neutralization. By flocculation-spectrophotometry, it was found that the absorbance of humic acid with the amount of each of the polymers dosed, changes sharply for polymers of high charge density, but changes rather broadly for polymers of low and middle charge density. Both methods showed that a stoichiometric correlation exists between the optimum dosage of each of the cationic polymers and the negatively charged humic acid.

Effects of Polyelectrolyte Dosage, Kaoline Particles and pH on Flocculation of Humic Acid by Cationic Polyelectrolytes

Kam, Sang-Kyu,Kim, Dae-Kyoung,Lee, Min-Gyu 한국환경과학회 2003 한국환경과학회지 Vol.12 No.8

Using a simple continuous optical technique, coupled with measurements of zeta potential, the effects of polyelectrolyte dosage, kaoline particles and pH on flocculation of humic acid by several cationic polyelelctrolytes, have been examined. The charge density of a polyelectolyte is important in determining the optimum dosage and in the removal of humic acid. The optimum dosage is less for the polyelectrolytes of higher charge density and is the same regardless of the presence of kaoline particles of different turbidity. At the dosage, the removal of humic acid is higher for the polyelectrolytes of higher charge density and the zeta potential of humic acid approaches to near zero. With increasing pH of humic acid, the optimum dosage increases and the flocculation index value obtained at the dosage decreases in the following sequences: pH 7> pH 5> pH 9, regardless of polyelectrolytes.

嫌氣性 流動床反應槽에 의한 豚舍廢水處理

朴炫建,全基一 진주산업대학교 농업기술연구소 1994 農業技術硏究所報 Vol.7 No.-

The objective of this study was to find the optimum operating conditions for the anaerobic fluidized bed reactor of swine waste. For this purpose, laboratory scale fluidized bed reactor were designed and operated under various conditions. 1. The COD removal efficiency was 70% in high COD loading rate 8-10kg COD/㎥. day and the optimum recycle ratio of anaerobic fluidized bed reactor was about 8-10 in COD loading rate 8.0kg COD/㎥.day. 2. As the hydraulic retention time decreased from 10, 2.5, 0.5days were 88%, 80%, 70% for COD removal efficiencies. 3. As the organic loading rate increased, the alkalinity and total volatile acid were 3,400-3,940mg/l,140-386mg/l(as caco_3) in the reactor. 4. When the hydraulic loading rate of soil filter were increased, the variation of COD removal efficiencies were between 95% and 82% then the effulent of COD were 95-215mg/l. 5. As the hydraulic loading rate of soil filter were increased, the removal efficiencies of suspended solid were about 84-65% and the effulent of SS were 7.9-22.3mg/l.

Acid protease 생산균 Penicillium sp. CK-2의 분리 및 효소생산

전동호,김진웅,권태종 건국대학교 산업기술연구원 2003 건국기술연구논문지 Vol.28 No.-

서울 시내 각 지역의 토양 및 하천수 230점을 대상으로 강력히 acid protease를 생산하는 균주인 CK-2를 선별하였으며 이 균주의 형태학적, 배양학적 특징을 조사한 결과 Penicillium속으로 동정하였으며 효소생산을 위한 최적조건을 조사하였다. 효소생산을 위한 최적 배지조성은 sucrose 1.0%, yeast extract 0.1%, (NH_4)_2SO_4 0.2%, K_2HPO_4 0.1%, MgSO_4·7H_2O 0.05%, FeSO_4·7H_2O 0.001% 였다. 최적 배양온도는 37℃였으나 30℃에서 50℃까지의 범위에서도 균체증식과 효소생산력이 우수하였으며, 최적 pH는 3.0, 37℃에서 54시간 배양하였을 때 최대효소활성을 보였으며 이때의 acid protease 활성은 980 unit/㎖이었다. Department of Microbial Engineering, Konkuk University, Hwayang-Dong 1, Kwangjin-Gu, Seoul 143-701, Korea, A fungi strain No. CK-2 producing extracellular acid protease was isolated from soil in acidic environment, and selected on bases of protease productivities as the only one of 230 isolates to produce high levels of acid protease. We are selected the best strain by soil-direct method. It was identified as Penicillium sp. based on its morphological and physiological characteristics. Image analyzer was used in investigation of the morphological characteristics. The optimal conditions for the enzyme production were Sucrose 1.0%, Yeast extract 0.1%, (NH_4)_2SO_4 0.2%, K_2HPO_4 0.1%, MgSO_4·7H_2O 0.05%, FeSO_4·7H_2O 0.001%, initial pH 3.0, incubation for 54hrs at 37℃. It grew in the temperature range of 30℃ to 50℃ and the pH range of pH 2.0 to 4.0.

Cloning, Overexpression, and Characterization of a Metagenome-Derived Phytase with Optimal Activity at Low pH

Tan, Hao,Wu, Xiang,Xie, Liyuan,Huang, Zhongqian,Gan, Bingcheng,Peng, Weihong The Korean Society for Microbiology and Biotechnol 2015 Journal of microbiology and biotechnology Vol.25 No.6

A phytase gene was identified in a publicly available metagenome derived from subsurface groundwater, which was deduced to encode for a protein of the histidine acid phosphatase (HAP) family. The nucleotide sequence of the phytase gene was chemically synthesized and cloned, in order to further overexpress the phytase in Escherichia coli. Purified protein of the recombinant phytase demonstrated an activity for phytic acid of 298 ± 17 µmol P/min/mg, at the pH optimum of 2.0 with the temperature of 37℃. Interestingly, the pH optimum of this phytase is much lower in comparison with most HAP phytases known to date. It suggests that the phytase could possess improved adaptability to the low pH condition caused by the gastric acid in livestock and poultry stomachs.

Choline chloride-based deep eutectic solvents as additives for optimizing chromatographic behavior of caffeic acid

Guizhen Li,Tao Zhu,Yingjie Lei 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.10

A series of deep eutectic solvents (DESs) were prepared using glycerol and choline chloride (ChCl), and Fourier transform infrared spectrometer (FT-IR) was used to analyze the spectra of glycerol, choline chloride and DESs based on glycerol and choline chloride. Then DESs were used as the additives of mobile phase to optimize chromatographic behavior of caffeic acid in high performance liquid chromatography (HPLC). A 17-run Box-Behnken design (BBD) was employed to evaluate effect of DESs as additives by analyzing the maximum theoretical plate number. Three factors, reaction temperature (60 oC, 80 oC, 100 oC), molar ratio of glycerol and choline chloride (2 : 1, 3 : 1, 4 : 1, n/n), and volume percent of additives (0.05%, 0.10%, 0.15%, v/v), were investigated in BBD. The optimum experiment condition was that of reaction temperature (80 oC), molar ratio of glycerol and ChCl (3 : 1, n/n), and volume percent of additive (0.10%, v/v). The mean chromatographic theoretical plate number of the caffeic acid this condition was 1567.5, and DESs as additives shorten the retention time and modify the chromatogram shape, proving DESs as additives for effective theoretical plate number and column efficiency in HPLC.

Shifting the Optimum pH of Bacillus circulans Xylanase towards Acidic Side by Introducing Arginine

Subarna Pokhrel,주정찬,유영제 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.1

Electrostatic interactions are important in protein folding, binding, flexibility, stability and function. The pH at which the enzyme is maximally active is determined by the pKas of the active site residues, which are modulated by several factors including the change in electrostatics in its vicinity. As the acidic xylanases are important in food and animal feed industries, electrostatic interactions are introduced in Bacillus circulans xylanase to shift their pH optima towards the acidic side. Arg substitutions are made to modulate the pKas of the active site residues. Neutral residues are substituted by Arg in such a way that the substituted residue can make direct interaction with the catalytic residues. However, the mutations with other titratable residues (Asp, Arg, Lys, His, Tyr, and Ser) present in between the catalytic sites and the substituted sites are avoided. Site directed mutagenesis was conducted to confirm the strategy. The results show the shift in pH optima of the mutants towards the acidic side by 0.5 - 1.5unit. Molecular dynamics simulation of the mutant V37R reveals that the decrease in activity is due to the increase in distance between the substrate oxygen atoms and catalytic glutamates.

Biochemical Characterization of a Psychrophilic Phytase from an Artificially Cultivable Morel Morchella importuna

( Hao Tan ),( Jie Tang ),( Xiaolin Li ),( Tianhai Liu ),( Renyun Miao ),( Zhongqian Huang ),( Yong Wang ),( Bingcheng Gan ),( Weihong Peng ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.12

Psychrophilic phytases suitable for aquaculture are rare. In this study, a phytase of the histidine acid phosphatase (HAP) family was identified in Morchella importuna, a psychrophilic mushroom. The phytase showed 38% identity with Aspergillus niger PhyB, which was the closest hit. The M. importuna phytase was overexpressed in Pichia pastoris, purified, and characterized. The phytase had an optimum temperature at 25°C, which is the lowest among all the known phytases to our best knowledge. The optimum pH (6.5) is higher than most of the known HAP phytases, which is fit for the weak acidic condition in fish gut. At the optimum pH and temperature, MiPhyA showed the maximum activity level (2,384.6 ± 90.4 μmol·min^-1·mg^-1, suggesting that the enzyme possesses a higher activity level over many known phytases at low temperatures. The phytate-degrading efficacy was tested on three common feed materials (soybean meal/rapeseed meal/corn meal) and was compared with the well-known phytases of Escherichia coli and A. niger. When using the same amount of activity units, MiPhyA could yield at least 3× more inorganic phosphate than the two reference phytases. When using the same weight of protein, MiPhyA could yield at least 5× more inorganic phosphate than the other two. Since it could degrade phytate in feed materials efficiently under low temperature and weak acidic conditions, which are common for aquacultural application, MiPhyA might be a promising candidate as a feed additive enzyme.

계절별ㆍ발효온도별 총각김치의 품질 특성의 변화

노정숙(Jeong Sook Noh),김현주(Hyun Ju Kim),권명자(Myung Ja Kwon),송영옥(Yeong Ok Song) 한국식품영양과학회 2009 한국식품영양과학회지 Vol.38 No.6

총각김치의 최적 숙성을 위한 발효온도 조건 확립 및 계절별 총각김치의 품질 특성에 대한 기초자료를 제시하고자 봄, 여름, 겨울 총각김치를 저장 온도에 따른 발효 양상을 살펴보았다. 총각김치의 pH의 변화는 계절별 김치의 영향보다는 저장 온도에 따른 영향이 컸다. 총각김치의 산도 변화는 계절 및 온도의 영향을 모두 받았는데, 발효 온도가 높을수록 계절의 영향이 크게 나타났다. 발효온도 15~20℃에서 저장한 봄 총각김치의 초기 산도 상승은 급격하였다. 이에 반해 여름 총각김치의 산도변화는 모든 발효 온도에서 가장 낮았는데 이는 여름무의 환원당의 함량이 가장 낮았기 때문으로 생각된다. Leuconostoc sp.와 Lactobacillus sp.의 증식은 전형적인 발효 양상을 따랐으며 10℃에서 발효시킨 총각김치의 유산균의 증식이 5℃에서 발효시킨 김치보다 활발한 것으로 나타났다. 총각김치의 조직감의 변화는 발효 온도보다는 계절적 영향이 큰 것으로 나타났다. 겨울 총각김치는 저장기간 중 김치의 조직감이 잘 유지되는데 반해 봄 및 여름총각김치는 담금 후 조직감이 급격히 감소하였다. 총각김치의 관능평가 중 종합적인 평가는 여름과 겨울김치가 유사하였으나 겨울 총각김치의 가식기간이 길었다. 관능검사에서 가장 높은 평가를 받은 총각김치는 10℃에서 발효시킨 겨울총각김치이었다. In order to establish the basic scientific data on the fermentation characteristics of chonggak kimchi (CGK), we studied with CGKs prepared at different seasons and stored at various temperatures (5~23℃). Changes in pH and acidity of CGK fermented at different temperatures were typical. However, acidity of summer CGK stored under 15℃ did not reach 1.0% since the amount of reducing sugar in the summer radish was lower by over 1% than the ones from the other seasons. Growths for Leuconostoc and Lactobacillus spp. over 8.0 logCFU/mL were observed in CGKs fermented above 10℃. Changes in Max G, cutting force, of CGK from different seasons were apparent. Max Gs for spring and summer CGK were decreased immediately right after storage while Max Gs for winter CGKs were increased slowly during storage. According to the results of sensory evaluation, CGKs revealed the highest overall acceptability when acidity of kimchi reached 0.7±0.1% under the given fermentation condition. However, CGK prepared with radish from winter or summer season tasted better than the one made in the spring. But the edible periods for winter CGKs were longer, compared with summer CGKs fermented at the same temperature. In conclusion, CGK fermented at 10℃ in the winter season gives a better taste with longer edible duration than the other CGKs.