• Korean Journal of Food Science and Technology
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• v.15 no.1
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• pp.56-61
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• 1983

Direct production of biomass from starch using amylolytic yeast, Sporobolomyces holsaticus FRI Y-5 was studied with varying the ratios between carbon and other nutrient sources in the medium. It was investigated under condition of constant C/P and C/S ratio to influence the initial concentration of starch $(S_o)$ and C/N ratio on its growth which is described as the specific growth rate $({\mu})$, cell yield (Y), the maximum concentration of cell $(X_m)$, and productivity (P). They were very dependent on both $S_o$ and C/N ratio. The form of the relationship between and ${\mu}$ and $S_o$ was observed to be similar to saturation kinetics at C/N = 100 but presented substrate inhibition at other C/N ratios. As $S_o$ was changed from 22.5 to 90 g/l, Y was observed to vary with C/N ratios but seemed to decrease as a wholes. $X_m$ was linearly related to $S_o$ at more than C/N = 50 but at less than C/N = 10 substrate inhibition was presented. P increased suddenly to $S_o$ = 45 g/l and then changed decreasingly at less than C/N = 50, but at more than C/N = 100 it changed increasingly. The effect of C/P ratio and C/S ratio on the yeast growth was also investigated at constant $S_o$ and C/N ratio. ${\mu}$ was dependent on C/P and C/S ratios, but Y, independent on them. But $X_m$ was reliant upon C/P ratio but not upon C/S ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.4
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• pp.301-306
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• 1992

In order to determine the optimal conditions for the process of acetic acid fermentation, the kinetics of Acetobacter aceti fermentation in submerged batch cultures were studied at different agitation speeds and air flow rates. The maximum cell concentration was noted after about 48 hr fermentation and the time course of Acetobactey aceti fermentation showed a distinct feature of growth-associated product formation. At agitation speeds 700, 500, and 300 rpm fixed on air flow rate 1 v/v/M, specific grow rates were $3.97\times10^{-2},\;3.82\times10^{-2},\;and\;2.04\times10^{-2\} \;hr^{-1}$, saturation constants were 61.4, 64.6, and 69.4mg/ml. and volumetric oxygen transfer coefficients were 0.9337, 0.4468, and 0.1701 $min^{-1},$ respectively. At air flow rates 1.25, 1.00, and 0.75 v/v/M fixed on agitation speed 500 rpm, specific growth rates were $3.90\times10^{-2},\;3.82\times10^{-2},\;and\;2.37\times10^{-2}\;hr^{-1}$, saturation constants were 63.4, 64.6, and 64.9 mg/ml, and volumetric oxygen transfer coefficient were 0.4923, 0.4468, and 0.3509 $min^{-1},$ respectively.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.215-221
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• 2005

It was characterized the hexane biodegradation and mineralization using a hexane-degrading consortium, and analyzed its bacterial community structure by 16S rDNA PCR-DGGE (denaturing gradient gel electrophoresis). The specific growth rate (${\mu}_{max}$) of the hexane-degrading consortium was 0.2 $h^{-1}$ in mineral salt medium supplemented with hexane as a sole carbon source. The maximum degradation rate ($V_{max}$) and saturation constant ($K_{s}$) of hexane of the consortium are 460 ${\mu}mol{\cdot}g-DCW^{-1}{\cdot}h^{-1}$ and 25.87 mM, respectively. In addition, this consortium could mineralize $49.1{\%}$ of $^{14}C$-hexane to $^{14}CO_2$, and $43.6{\%}$ of $^{14}C$-hexane) was used for the growth of biomass. The clones isolated from the DGGE bands were closely related to the bacteria which were capable of degrading pollutants such as oil, biphenyl, PCE, and waste gases. The hexane-degrading consortium obtained in this study can be applied for the biological treatment of hexane.

• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.1-8
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• 2007

A series of batch and column experiments were conducted for the development of biobarrier technology which can be applied to containment and reduction of contaminants in soil and ground waters. The growth kinetic constants of Pseudomonas fluorescens on glucose or molasses were determined using batch experiments. The maximum specific growth rate (Vmax) of P. fluorescens at $23^{\circ}C$ on glucose or molasses were $0.246\;hr^{-1}$ and $0.073\;hr^{-1}$, respectively. However, molasses was selected as carbon source due largely to the absence of lag phase of P. fluorescens growth on molasses and economic reason. In constant head column experiments, the hydraulic conductivity of the column soil reduced by $6.8{\times}10^{-3}$ times from $4.1{\times}10^{-2}cm/sec$ to $2.8{\times}10^{-4}cm/sec$ after the inoculation of P. fluorescens and administration of carbon source and nutrients. The biomass concentration was observed highest in the column inlet. Measurements of carbon source and electron accepter (dissolved oxygen) concentration showed that the growth of P. fluorescence, which is the main reason for hydraulic conductivity reduction, was limited not by the concentration of carbon source but by the concentration of electron acceptor.

• KSBB Journal
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• v.10 no.3
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• pp.241-248
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• 1995

For the treatment of poorly biodegradable polyvinyl alcohol(PVA) in dye-processing wastewater, immobilized microbial beads were prepared by uslng agar-acrylamide method. PVA removal efficiency for the synthetic wastewater was 85% at the PVA volume loading rate of $3.1g/\ell$.day. In case of real desizing wastewater, PVA removal efficiency was 81.3% at the PVA volume loading rate of $3.25g/\ell$.day. In observation of cross section of immobilized bead passed 5 months with diameter of 2.4mm, the growth of cell was limited by the resistance of substrate and oxygen transfer for the inners region of more than 48% of bead radius from the surface. It was estimated that 70% of total removed PVA was degraded by the immobilized cells in the continuous immobilized reactor. Substrate utilization rate in the suspended reactor was decreased with increasing dilution rates above 0.083 hr-1, but that in the immobilized reactor was increased with increasing dilution rates up to 0.125hr-1. The substrate removal efficiency of immobilized reactor was much superior to that of suspended reactor with increasing dilution rates. Saturation constant of substrate utilization rate equation, Ks was $6.6 g PVA/\ell$, and maximum specific substrate utilization. k was 0.175g PVA/g cell.hr

• KSBB Journal
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• v.24 no.4
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• pp.377-382
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• 2009

The culture condition of growing Chlorella minutissima was optimized to produce biodiesel for fed-batch cultivation. First, under heterotrophic cultivation, the optimum level of glucose was determined to be 10 g/L for 20 days. After, three cultivation conditions were operated: autotrophic, heterotrophic, and mixotrophic growth. The lipid level and the maximum cell concentration from the fed-batch heterotrophic process were 32.0 (%, v/v) and 15.0 (g-dry wt./L) in 20 L flask, respectively. In addition, since the relatively constant specific lipid production rate was observed as 0.040 (% lipid/g-dry wt./day) at the latter period of cultivation time, the fed-batch process could maintain continuous lipid production. Fed-batch process is higher than those values from the batch process. The lipids from the fed-batch process contained over 38% of $C_{18}$, known as the suitable composition for the biodiesel application. For mixotrophic and heterotrophic growth under fed-batch condition, glucose was proved to be an appropriate carbon source for a large scale outdoor cultivation. For fed-batch cultivation, the feeding rate of seawater medium containing glucose was decided to be 0.5 L/day. The mixotrophic cultivation maintained maximum cell concentration of 24 (g-dry wt./L) and the lipid level of 43 (%, w/w). The lipid composition from this process was also proved to be suitable for the biodiesel production. The fatty acids from the mixotrophic growth contains 18% of $C_{17}$ and 49% of $C_{18}$, implying It also tells that C. minutissima is a suitable resource of biodiesel. Especially, the mixotrophic cultivation with fed-batch process might be useful for the large scale cultivation for the biodiesel production.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1219-1225
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• 2010

Actinobacillus succinogenes, a representative succinicacid-producing microorganism, is seriously inhibited by ammonium ions, thereby hampering the industrial use of A. succinogenes with ammonium-ion-based materials as the pH controller. Therefore, this study isolated an ammonium-ion-tolerant mutant of A. succinogenes using a continuous-culture technique in which all the environmental factors, besides the stress (ammonium ions), were kept constant. Instead of operating the mutant-generating system as a nutrient-limited chemostat, it was used as a nutrient-unlimited system, allowing the cells to be continuously cultured at the maximum specific growth rate. The mutants were isolated on agar plates containing the acid-base indicator bromothymol blue and a high level of ammonium ions that would normally kill the parent strain by 100%. When cultured in anaerobic bottles with an ammonium ion concentration of 354 mmol/l, the mutant YZ0819 produced 40.21 g/l of succinic acid with a yield of 80.4%, whereas the parent strain NJ113 was unable to grow. When using $NH_4OH$ to buffer the culture pH in a 3.0 l stirredbioreactor, YZ0819 produced 35.15 g/l of succinic acid with a yield of 70.3%, which was 155% higher than that produced by NJ113. In addition, the morphology of YZ0819 changed in the fermentation broth, as the cells were aggregated from the beginning to the end of the fermentation. Therefore, these results indicate that YZ0819 can efficiently produce succinic acid when using $NH_4OH$ as the pH controller, and the formation of aggregates can be useful for transferring the cells from a cultivation medium for various industrial applications.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.212-219
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• 2016

The bioavailability of dissolved organic nitrogen (DON) by dominant species Chaetoceros debilis and Leptocylindrus danicus under dissolved inorganic nitrogen (DIN)-limited condition in the southwestern East Sea was conducted to assess the quantitative evaluation using growth kinetic experiment. Nitrogen sources were nitrate and ammonium as DIN, glycine and urea, which is portion component of DON in East Sea. Maximum specific growth rate (${\mu}_{max}$) and half-saturation constant ($K_s$) of C. debilis calculated from Monod equations were estimated to be $1.50day^{-1}$ and $1.62{\mu}M$ in nitrate, $1.13day^{-1}$ and $6.97{\mu}M$ in ammonium, $1.46day^{-1}$ and $3.36{\mu}M$ in glycine, $0.93day^{-1}$ and $0.55{\mu}M$ in urea, respectively. Also, L. danics was estimated to be $1.55day^{-1}$ and $5.21{\mu}M$ in nitrate, $1.57day^{-1}$ and $4.57{\mu}M$ in ammonium, $1.47day^{-1}$ and $3.80{\mu}M$ in glycine, $1.42day^{-1}$ and $1.94{\mu}M$ in urea, respectively. Both C. debilis and L. dancius have higher affinity of urea than DIN. The high affinity of urea was indicated that the dominant species were able to growth using urea under DIN-limited conditions. Thus, DON utilization of phytoplankton may be one of the important dominant strategy under DIN-limited environments such as southwestern East Sea.