• Asian-Australasian Journal of Animal Sciences
• /
• v.19 no.11
• /
• pp.1588-1596
• /
• 2006

An experiment was conducted to study the effect of different dietary protein levels on the performance, nutrient balances, blood biochemical parameters and thyroid hormones of crossbred calves. Thirty crossbred (Bos taurus${\times}$Bos indicus) calves aged 3-5 months were divided into 3 equal groups of 10 each and fed graded levels of crude protein, namely 100 (NP), 75 (LP) and 125 (HP) percent of the Kearl recommendations for 105 d. The calves had access to ad libitum oat hay as the basal roughage. A metabolism trial of 6 d duration was conducted at 90 d of the study. Blood collection and its analysis for various hematological and biochemical parameters as well as thyroid hormones was done both during the pre- and post-experimental periods. The fortnightly body weight changes and the net gain did not differ significantly due to dietary variation. The average daily gain was $367{\pm}21.6$, $347{\pm}22.9$ and $337{\pm}26.4g$ in calves fed NP, LP and HP diets, respectively. Averaged across the feeding trial, oat hay intake was higher (p<0.05) in NP animals than HP or LP fed groups. The dry matter (DM) intake showed no significant difference between the 3 groups but the DM digestibility was higher (p<0.05) in the HP fed animals. The digestibility of crude protein, organic matter, crude fiber and nitrogen-free extract was significantly higher (p<0.05) on HP diets compared to LP or NP diets. The calves on all 3 diets were in positive nitrogen (N) balance, however the N retention was higher (p<0.05) in HP than in LP fed calves. The intake and retention of calcium and phosphorus were similar between the treatments. The blood biochemical profile revealed no significant influence of the dietary treatments on hemoglobin, packed cell volume as well as serum levels of glucose, total protein, albumin, globulin, Ca, P, and alkaline phosphatase. Serum levels of the circulating thyroid hormones ($T_3$ and $T_4$) tended to be lower (p>0.05) on feeding of the LP diet besides showing an increasing trend with the advancement of age. Considering the similar performance and metabolic profile, it could be concluded that crossbred calves can be satisfactorily reared on 25% lower protein level as recommended by Kearl for developing countries, which would not only economize the cost of production but also help to reduce environmental pollution attributable to livestock production.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.2
• /
• pp.219-226
• /
• 1995

A study was made of the concentration of the naturally occurring radionuclide $^{210}Po$ in seawater, plankton and fishes collected from Yongil Bay, Korea, in summer 1993. The mean value of the $^{210}Po$ concentration in sea water was determined to be about 1.9 mBq/l, with the proportion of the dissolved forms being about $46\%$. The mean $^{210}Po$ concentration factor in the centric diatom Skeletonema costatum, comprises > $95\%$ of the total phytoplankton cell number, was $7.6\times10^4$. Of five species of zooplankton examined, four species (two copepods and two mysids) had $^{210}Po$ concentrations in the range of $^{210}Po$ mBq/g dry weight. A copepod Labidocera bipinnata, however, was exceptional with a particularly high $^{210}Po$ level of 2,070 mBq/g. This indicates that L. bipinnata is primarily a raptorial feeder. The concentration of $^{210}Po$ in the pyloric caecum of pelagic fishes was 2,979-3,811 mBq/g, with the concentration factors of $3.4-4.3\times10^6$. The food chain concentration of $^{210}Po$ occurred as follows: phytoplankton < filter feeding copepods < omnivorous mysids < raptorial copepod < pelagic fishes.

• Microbiology and Biotechnology Letters
• /
• v.34 no.1
• /
• pp.63-69
• /
• 2006

We isolated a bacterium which produces antifungal substances from the Lake of Saimaa soils in Fin-land. The isolated strain was identified as Bacillus sp. and shown a strong antifungal activity on plant pathogenic fungi. Bacillus sp. KMU-1011 produced maximum level of antifungal substances under incubation aerobically at $24^{\circ}C$ for 48 hours in nutrient broth containing 1.0% glucose and 1.0% polypeptone at 180 rpm and initiated pH adjusted to 6.0. Precipitate of culture broth by $30{\sim}60%$ ammonium sulfate precipitation exhibited strong antifungal activity against Botrytis cinerea KACC 40573 by dry cell weight. Chloroform extract of cultured broth also shown fungal growth inhibitory activity against C. gloeosporioides KACC 40804, D. bryoniae KACC 40669, F. oxysporum KACC 40037, F. oxysporum KACC 40052, F. oxysporum f. sp. radicis-lycopersici KACC 40537, F. oxysporum KACC 40902, M. cannonballus KACC 40940, P. cambivora KACC 40160, R. solani AG-1 KACC 40101, R. solani AG-4 KACC 40142, and S. scleotiorum KACC by agar diffusion method.

• Microbiology and Biotechnology Letters
• /
• v.41 no.2
• /
• pp.207-214
• /
• 2013

A concerted effort to develop alternative forms of energy is underway due to fossil fuel shortages and its deleterious effects. Recently, bioenergy from microalgae has gained prominence and the use of municipal wastewater as a low cost alternative for a nutrient source has significant advantages. In this study, we have employed municipal wastewater directly after primary treatment (primary settling basin) in a small scale raceway pond (SSRP) for microalgal growth. Indigenous microalgae in the wastewater were encouraged to grow in the SSRP under optimal conditions. The mean removal efficiencies of TN, TP, and $NH_3-N$ after 6 days were 77.77%, 63.55%, and 89.02%, respectively. The average lipid content of the microalgae was 19.51% of dry cell weight, and linolenate and linoleate (18:n) were the predominant fatty acids. The 18S rRNA gene analysis and microscopic observations of the indigenous microalgae community revealed the presence of Chlorella vulgaris and Scenedesmus obliquus as the dominant microalgae. These results indicate that untreated municipal wastewater, serving as an excellent nitrogen and phosphate source for microalgal growth, could be treated using microalgae in open raceway ponds. Moreover, microalgal biomass could be further profitable by the extraction of biodiesel.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.2
• /
• pp.238-246
• /
• 2015

A unicellular red microalga was isolated from environmental freshwater in Korea, and its morphological, molecular, and biochemical properties were characterized. Morphological analysis revealed that the isolate was a unicellular biflagellated green microalga that formed a non-motile, thick-walled palmelloid or red aplanospore. To determine the taxonomical position of the isolate, its 18S rRNA and rbcL genes were sequenced and phylogenetic analysis was performed. We found that the isolate was clustered together with other related Haematococcus strains showing differences in the rbcL gene. Therefore, the isolated microalga was classified into the genus Haematococcus, and finally designated Haematococcus sp. KORDI03. The microalga could be cultivated in various culture media under a broad range of pH and temperature conditions. Compositions of the microalgal cellular components were analyzed, and its protein, carbohydrate, and lipid compositions were estimated to be 21.1 ± 0.2%, 48.8 ± 1.8%, and 22.2 ± 0.9%, respectively. In addition, D-glucose and D-mannose were the dominant monosaccharides in the isolate, and its amino acids were composed mainly of aspartic acid, glutamic acid, alanine, and leucine. Moreover, several polyunsaturated fatty acids accounted for about 80% of the total fatty acids in Haematococcus sp. KORDI03, and the astaxanthin content in the red aplanospores was estimated to be 1.8% of the dry cell weight. To the best of our knowledge, this is the first report of an Haematococcus sp. isolated from Korea, which may be used for bioresource production in the microalgal industry.

• Korean Journal of Microbiology
• /
• v.53 no.3
• /
• pp.200-207
• /
• 2017

A new approach to the solubilization of waste activated sludge (WAS) using alginate-quaternary ammonium complex beads was investigated under controlled mild alkaline conditions. The complex beads were prepared by the reaction of sodium alginate (SA) with 3-(trimethoxysilyl)propyl-octadecyldimethylammonium chloride (TSA) in acid solution, followed by crosslinking with $CaCl_2$. Treatment of WAS with SA-TSA complex beads was effective for enhancing the efficacy of WAS solubilization. The highest value of soluble chemical oxygen demand (SCOD) concentration (3,900 mg/L) was achieved after 10 days of treatment with 30% (v/v) SA-TSA complex beads. The WAS solubilization efficacy of the complex beads was also evaluated by estimating the concentrations of volatile fatty acids (VFAs). The maximum value of VFAs was 2,961 mg/L, and the overall proportions of VFAs were more than 75% of SCOD. The main components of VFAs were acetic, propionic, iso-butyric, and butyric acids. These results suggest that SA-TSA complex beads might be useful for enhancing the solubilization of WAS. The potential use of VFAs as the external carbon substrate for the production of polyhydroxyalkanoate (PHA) by a mixed microbial culture (MMC) was also examined. The enrichment of PHA-accumulating MMC could be achieved by periodic feeding of VFAs generated from WAS in a sequencing batch reactor. The composition of PHA synthesized from VFAs mainly consisted of 3-hydroxybutyrate. The maximum PHA content accounted for 25.9% of dry cell weight. PHA production by this process is considered to be promising since it has a doubly beneficial effect on the environment by reducing the amount of WAS and concomitantly producing an eco-friendly biopolymer.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.38 no.5
• /
• pp.442-448
• /
• 1993

The aims of the work were to examme the variability induced by EMS (ethyl methanesulfonate) mutagenesis of soybean plants, and to isolate mutants altered in nodulation and other growth characters. Seeds of two soybean cultivars, ‘Hwanggeumkong’ and ‘Baegunkong’ were treated with 30 and 50mM EMS(pH 7.0) for 6 hours and were planted directly in the field. Field emergency of$M_1 seed was averaged to be 61.0%, and frequency of plants with chlorophyll-deficient sectors of the first trifoliolate is about 0.7%. Regardless of varieties and does of EMS, $M_1 plant injury at harvest was present in plant height, pod and seed number per plant when compared to those of original-type soybean plants. The $M_2 variability of nodulation process induced by EMS treatment was found to be narrower than that of shoot dry weight. On the basis of the occurrence of chlorophyll-deficient plants, mutated cell frequency within $M_1 seed ranged from 5.3% to 84.2%, suggesting that mutation frequency on the $M_1 seed induced by EMS occurred partly and randomly regardless of varieties and doses of EMS. The putative mutant, which had more nodulation than original-type plant, was short in plant height. Sparse-nodulating soybean mutant was lower in leaf chlorophyll content and showed reduced growth.

• Journal of Mushroom
• /
• v.16 no.3
• /
• pp.162-170
• /
• 2018

To improve the productivity of Pleurotus ostreatus, different conditions of liquid spawn culture were tested. The optimum culture conditions were potato dextrose broth, incubation temperature of $22^{\circ}C$, and pH 6. Fifteen different media ('A' to 'O') containing 0.3% soybean meal (SM) were prepared by varying sugar and glucose contents. The cultures were propagated in SM media for 14 days, at $22^{\circ}C$, and pH 6. Their absorbances were higher after 14 days of incubation in the media containing both sugar and glucose. In particular, the absorbance of media containing 5 to 20% of glucose alone ('C', 'D', 'E', and 'F') tended to increase in the incubation period. Dry cell weight was lower in media containing less than 20% sugar or glucose alone than in media containing 30% sugar ('A') or 30% glucose ('B') alone. In sawdust media, in 900 mL-bottle, the optimum inoculation volume of liquid spawn was 15 to 20 mL. The texture of the mushroom cultivated with the liquid spawn was superior to that cultivated in the solid spawn.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.20 no.1
• /
• pp.78-86
• /
• 2012

In this study, dark fermentative hydrogen production (DFHP) from acid pretreated microalgal biomass was optimized with via statistical experimental design. Acid concentration and reaction time were varied from 0.1 to 3% (v/w) and 10 to 60 min with substrate concentration of 76 g dry cell weight (dcw)/L and initial pH of 7.4, respectively. During the fermentation, pH was not controlled. The optimal condition was found that at $H_{2}$ yield reached to 37.3 mL $H_{2}/g$ dcw at 1.2% HCl and 48 min. Through regression analysis, it was found that $H_{2}$ yield was well fitted by a quadratic polynomial equation ($R^{2}$=0.95). HCl concentration was the most significant factor influencing DFHP. The results of ANOVA verify that HCl concentration was the most significant factor influencing DFHP.

• Microbiology and Biotechnology Letters
• /
• v.34 no.3
• /
• pp.235-243
• /
• 2006

The study was performed to identification of producing microbe Non-Cariogenicity Sugar (NCS; Fuc($1{\to}4$) gaINAc($2{\to}6$)NeuAc) with anti-caries activity, and to optimization of production condition. A typical strain which produced the NCS was identified alkalophilic Bacillus sp. S-1013 through the results of morphological, biochemical and chemotaxonomic characteristics and 16S rDNA sequencing. The optimal medium composition for the maximal production of the NCS from alkalophilic Bacillus sp. S-1013 was as follow: soluble starch 30 g, dextrin 15 g, yeast extract 5 g, peptone 10 g, $K_{2}HPO_4$ 2 g in a liter of distilled water. Optimal temperature and pH were 25 and 11.0, respectively. The highest production of NCS was shown 60 hrs cultivation using the optimal medium, and then NCS productivity and dry cell weight of culture broth increased 4.24 and 2.67 time than initial medium, respectively.