• Journal of Biosystems Engineering
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• v.35 no.1
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• pp.53-63
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• 2010

The performance of two serial completely stirred tank reactors (CSTRs) for treatment of swine manure (SM) with Chinese cabbage silage (CCS) was studied. The two CSTRs of 41 liters each were connected in series and first reactor was fed swine manure with Chinese cabbage silage in 3:1 proportion by VS basis. The FOS/TAC, methane content (%) and pH were utilized as the parameters for the digester stability control. The FOS/TAC value was found to be effective indicator for instant digester condition. The stability of reactors can be obtained with the FOS/TAC value up to 1.0 with accumulation of FOS value below 10,000 mg/L. Material exchange method was effective in transferring the excess volatile fatty acids (VFA) from the first reactor to the second one and maintaining stability in both the reactors. The biogas yield and the methane yield was 0.55-0.61 and 0.41-0.42 L/g VS fed, respectively, at organic loading rate (OLR) of 2.2-2.6 g VS/L with total HRT of 32 days.

• Membrane and Water Treatment
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• v.10 no.3
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• pp.213-221
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• 2019

Anaerobic digestion (AD) has been widely used to valorize food waste (FW) because of its ability to convert organic carbon into $CH_4$ and $CO_2$. Korean FW has a high content of fruits and vegetables, and efficient hydrolysis of less biodegradable fibers is critical for its complete stabilization by AD. This study examined the digestates from different anaerobic digesters, namely Rs, Rr, and Rm, as the inocula for the AD of vegetable waste (VW) and cellulose (CL): Rs inoculated with anaerobic sludge from an AD plant, Rr inoculated with rumen fluid, and Rm inoculated with anaerobic sludge and augmented with rumen fluid. A total of six conditions ($3\;inocula{\times}2\;substrates$) were tested in serial subcultures. Biogas yield was higher in the runs inoculated with Rm than in the other runs for both VW (up to 1.10 L/g VS added) and CL (up to 1.05 L/g VS added), and so was biogas production rate. The inocula had different microbial community structures, and both substrate type and inoculum source had a significant effect on the formation and development of microbial community structures in the subcultures. The overall results suggest that the bioaugmentation with rumen microbial consortium has good potential to enhance the anaerobic biodegradability of VW, and thereby can help more efficiently digest high fiber-content Korean FW.

• Journal of Microbiology
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• v.43 no.6
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• pp.546-554
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• 2005

We assessed the genetic relations and epidemiological links among bloodstream isolates of Candida albicans, which were obtained from a university hospital over a period of five years. The 54 bloodstream isolates from the 38 patients yielded 14 different karyotypes, 29 different patterns after digestion with SfiI (REAG-S), and 31 different patterns after digestion with BssHII (REAG-B) when analyzed using three different pulsed-field gel electrophoresis (PFGE) typing methods. In 11 patients with serial blood stream isolates, all strains from each patient had the same PFGE pattern. The dendrograms for all of the strains revealed that the distribution of similarity values ranged from 0.70 to 1.0 in the REAG-S patterns, and from 0.35 to 1.0 in the REAG-B patterns. Overall, the combination of the three different PFGE methods identified 31 distinct types, reflecting the results obtained using the REAG-B alone different. different Five PFGE types were shared among 22 isolates from 12 patients. These types of strains were more frequently associated with central venous catheter-related fungemia than the other 26 type strains $(92\%\;versus\;31\%;\;P<0.005)$. Of five PFGE types, four isolates were determined to be epidemiologically related: each of these types was primarily from two or three patients who had been hospitalized concurrently within the same intensive care unit. Our results suggest that the REAG-B constitutes perhaps the most useful PFGE method for investigating C. albicans candidemia and also shows that a relatively high proportion of C. albicans candidemia may be associated with exogenous acquisition of clonal strains.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.130-139
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• 2000

Serial basic tests were conducted for the determination of fundamental kinetics and for the actual application of kinetic parameter to food waste digestion with precise measurement of methane production under a thermophilic condition. The effects of food particle size, sodium ion concentration, and volatile solid (VS) loading rate on the anaerobic thermophilic food waste digestion process were investigated. Results of serial test for the determination of fundamental kinetic coefficients showed the value of k (maximum substrate utilization rate coefficient) and KS (half-saturation coefficient) as $0.24hr^{-1}$ and $700mg/{\ell}$, respectively, for non-inhibiting organic loading range. No inhibition effect was shown until $5g/{\ell}$ of sodium ion concentration was applied to a serum bottle reactor. However, the volume of methane gas was decreased gradually when the concentrations of more than $5g/{\ell}$ of sodium ion applied. All sizes of food waste particle showed the same constants (A : 0.45) but the maximum substrate utilization rate constant ($k_{HA}$) was inversely proportional to particle size. As an average particle size increased from 1.02 mm to 2.14 mm, $k_{HA}$ decreased from $0.0033hr^{-1}$ to $0.0015hr^{-1}$. The result reveals that particle size is one of the most important factors in anaerobic food waste digestion. There was no inhibition effect of sodium ion when VS loading rate was $30g/{\ell}$. And maximum injection concentration of VS loading rate was determined about $40g/{\ell}$.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.127-131
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• 2002

The qualitative and quantitative changes of bacterial flora associated with the Pure Mysore (Multivoltine) and NB$_4$D$_2$ (Bivoltine) silkworm (Bombyx modi L.) midgut during third, fourth and fifth instars were studied. Larvae reared on mulberry leaves were dissected and their midgut bacterial populations were enumerated through serial dilution technique and after 72 hrs of incubation period at 28 $\pm$ 1$^{\circ}C$, the bacterial population was estimated. The results showed a highest mean value of 15$\times$10/ sup 6/ sup 6/ CFU/g and 28$\times$10/ sup 6/ CFU/g in Pure Mysore and NB$_4$D$_2$races, respectively, in midgut tissue of fifth instar larvae. The natural epiphytic microflora of mulberry leaves fed during the respective instars was also studied and found maximum 14$\times$10$^3$ CFU/g in leaves fed in third instars, followed by 5.3$\times$10$^3$ CFU/g and 2.1$\times$10$^3$ CFU/g in leaves fed during fourth and fifth instars, respectively. The bacterial flora colonized in midgut was found to be elaborating amylase, caseinase, gelatinase, lipase and urease enzymes. The highest percentages of isolates were amylase producers followed by protein and lipid splitters in Pure Mysore, whereas in NB$_4$D$_2$ protein splitter were dominated followed by lipase and amylase producers in NB$_4$D$_2$. The results indicate that the natural microflora may play a vital role in the digestion of ingested food materials in silkworms.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.114-120
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• 2006

Anti-diabetic effects of extracts and fractions of Sasa borealis (SB), white lotus roots (LR) and leaves (LL), and their mixture were determined in 3T3-L1 adipocytes and Min6 cells by investigating insulin-sensitizing activity and glucose-stimulated insulin secretion, respectively. SB, LR, LL, and mixture of SB, LR, and LL (3 : 2 : 3) were extracted using 70% ethanol, and m mixture extract was fractionated by XAD-4 column chromatography with serial mixture solvents of methanol and water. Fractional extractions were utilized for anti-diabetic effect assay. SB and LR extracts increased insulin-stimulated glucose uptake, but not as much as mixture of SB, LR, and LL. Significant insulin-sensitizing activities of 20 and 80% methanol fractions of SB, LR, and LL mixture extract were observed in 3T3-L1 adipocytes, giving 0.5 or $5\;{\mu}g/mL$ each fraction with 0.2 nM insulin to attain glucose uptake level similar to that attained by 10 nM insulin alone. Similar to pioglitazone, peroxisome proliferators-activated $receptor-{\gamma}\;(PPAR-{\gamma})$ agonist, 20 and 80% methanol fractions increased adipocytes by stimulating differentiation from fibroblasts and triglyceride synthesis. LL extract and 20, 60, and 80% methanol fractions of the mixture suppressed ${\alpha}-amylase$ activity, but did not modulate insulin secretion capacity of Min6 cells in both low and high glucose media. These data suggest 20 and 80% methanol tractions contain potential insulin sensitizers with functions similar to that of $PPAR-{\gamma}$ agonist. Crude extract of SB, LR, and LL mixture possibly improves glucose utilization by enhancing insulin-stimulated glucose uptake and inhibiting carbohydrate digestion without affecting insulin secretion in vivo.