• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.1
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• pp.32-39
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• 2000

Simultaneous isomerisation and fermentation (SIF) of xylose and simultaneous isomerisation and cofermentation (SICF) of glucose-xylose mixture was carried out by the yeast Saccharomyces cerevisiae in the presence of a compatible xylose isomerase. The enzyme converted xylose to xylulose and S. cerevisiae fermented xylulose, along with glucose, to ethanol at pH 5.0 and $30^{\circ}C$. This compatible xylose isomerase from Candida boidinii, having an optimum pH and temperature range of 4.5-5.0 and $30-35^{\circ}C$ respectively, was partially purified and immobilized on an inexpensive, inert and easily available support, hen egg shell. An immobilized xylose isomerase loading of 4.5 IU/(g initial xylose) was optimum for SIF of xylose as well as SICF of glucose-xylose mixture to ethanol by S. cerevisiae. The SICF of 30 g/L glucose and 70 g xylose/L gave an ethanol concentration of 22.3 g/L with yield of 0.36 g/(g sugar consumed) and xylose conversion efficiency of $42.8\%$.

• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.36-40
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• 1996

For the production of cis, cis-muconic acid via biocatalytic conversion reactions from a toxic cosubstrate, benzoic acid, a fed-batch process using computer-controlled DO-stat feeding was developed. The mutant strain of Pseudomonas putida BM014 produced cis, cis-muconic acid from benzoic acid with high conversion yield. More than 32 g/L of cis, cis-muconic acid was accumulated in 42h and a productivity of 1.4g/(L.h)was achieved.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.384-388
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• 2001

The metabolic pathway synthesis algorithm was applied to estimate the maximum ethanol yield from xylose in a model recombinant Saccharomyces cerevisiae strain containing the genes involved in xylose metabolism. The stoichiometrically independent pathways were identified by constructing a biochemical reaction network for conversion of xylose to ethanol in the recombinant S. cerevisiae. Two independent pathways were obtained in xylose-assimilating recombinant S. cerevisiae as opposed to six independent pathways for conversion of glucose to ethanol. The maximum ethanol yield from xylose was estimated to be 0.46 g/g, which was lower than the known value of 0.51 g/g for glucose-fermenting and wild-type xylose-fermenting yeasts.

• Journal of Microbiology
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• v.41 no.4
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• pp.335-339
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• 2003

Many genetic variants of ${\alpha}_1$-antitrypsin have been associated with early onset emphysema and liver cirrhosis. However, the detailed structural basis of pathogenic ${\alpha}_1$-antitrypsin molecules is rarely known. Here we found that a recombinant $M_{malton}$ variant (Phe52-deleted) lost inhibitory activity by spontaneous conformational conversion into a more stable, inactive form under physiological conditions. Biochemical and spectroscopic data suggested that the variant converts into a reactive center loop-inserted conformation, resembling the latent form of plasminogen activator inhibitor-1.

• Journal of Animal Science and Technology
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• v.62 no.4
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• pp.468-474
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• 2020

The study was to determine the effects of diverse concentrations of T-2 toxin in broiler diet. Three hundred 1-day-old chicks with initial body weight of 46 ± 0.52 g were chosen and randomly assigned into five dietary treatments with 5 replicate cages and 12 broilers per cage for 42 d feeding trial. Dietary treatments were prepared with basal diets containing 0 (T₁), 50 (T₂), 100 (T₃), 150 (T₄), 200 (T₅) ppb T2-toxin. Significant results were observed in the decreased intake of feed, feed conversion ratio (FCR), body weight gain (BWG), level of serum protein, cholesterol and hemoglobulin of broilers in increased concentration of the T-2 toxin in diet (150 and 200 ppb) groups than control. Also, observed that the uric acid, serum glutamic pyruvic transferase (SGPT), serum glutamic oxaloacetic transferase (SGOT) and Heterophil/Lymphocyte (H/L) ratio value were significantly higher (p < 0.05) in groups T₄ and T₅ than control. However, the BWG, feed intake and FCR, as well blood biochemical profiles of serum protein, cholesterol, hemoglobulin, uric acid, SGPT, SGOT and H/L ratio in groups T₂ and T₃ were statistically similar to control diet of broilers. It was concluded that the results showed that no adverse effects on growth performance and blood biochemical parameters in broilers feed with T-2 toxin (50 and 100 ppb) during the entire trial.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.2
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• pp.246-249
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• 2011

The present study was carried out on broilers to study the effect of oral administration of vitamin E and selenium (E-care Se) on growth performance, haematological and biochemical parameters for a period of 42 days (6 weeks). A total of 90 oneday-old broiler chicks were divided into three equal groups: $T_1$, $T_2$ and $T_3$. Group T1 was maintained as control and was fed only with the basal diet throughout the experimental period. Two experimental diets, $T_2$ and $T_3$, were formulated to contain an additional 100 g (150 IU vitamin E/kg+0.5 mg Se/kg) and 200 g (300 IU vitamin E/kg+1.0 mg Se/kg) of E-care Se which was the source of vitamin E and selenium. Body weight was significantly (p<0.05) higher in antioxidant-treated groups compared to the control group. There were no significant differences in feed conversion ratio (FCR). Blood samples were collected from the jugular vein for haematological (TEC, Hb, PCV and ESR) and biochemical (GOT and GPT) study. Body weight was increased significantly in both treated groups compared with the control group and highest body weights were recorded in group $T_2$. TEC, PCV and Hb content increased significantly (p<0.01) in the treated groups as compared to the control group, but ESR, GOT and GPT values decreased significantly (p<0.01) in both treated groups as compared to the control group. The result reveals that use of antioxidants (vitamin E and selenium) is an effective way of getting the best result in terms of body weight gain and haemato-biochemical profiles in broiler birds at high altitude.

• Journal of Microbiology and Biotechnology
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• v.30 no.11
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• pp.1750-1759
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• 2020

The characterization of cytochrome P450 CYP125A13 from Streptomyces peucetius was conducted using cholesterol as the sole substrate. The in vitro enzymatic assay utilizing putidaredoxin and putidaredoxin reductase from Pseudomonas putida revealed that CYP125A13 bound cholesterol and hydroxylated it. The calculated K_D value, catalytic conversion rates, and Km value were 56.92 ± 11.28 μM, 1.95 nmol min^-1 nmol^-1, and 11.3 ± 2.8 μM, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis showed that carbon 27 of the cholesterol side-chain was hydroxylated, characterizing CYP125A13 as steroid C27-hydroxylase. The homology modeling and docking results also revealed the binding of cholesterol to the active site, facilitated by the hydrophobic amino acids and position of the C27-methyl group near heme. This orientation was favorable for the hydroxylation of the C27-methyl group, supporting the in vitro analysis. This was the first reported case of the hydroxylation of cholesterol at the C-27 position by Streptomyces P450. This study also established the catalytic function of CYP125A13 and provides a solid basis for further studies related to the catabolic potential of Streptomyces species.

• Journal of Microbiology and Biotechnology
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• v.33 no.3
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• pp.387-397
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• 2023

Cytochrome P450 (CYP) is a heme-containing enzyme that catalyzes hydroxylation reactions with various substrate molecules. Steroid hydroxylases are particularly useful for effectively introducing hydroxyl groups into a wide range of steroids in the pharmaceutical industry. This study reports a newly identified CYP steroid hydroxylase (BaCYP106A6) from the bacterium Bacillus sp. and characterizes it using an in vitro enzyme assay and structural investigation. Bioconversion assays indicated that BaCYP106A1 catalyzes the hydroxylation of progesterone and androstenedione, whereas no or low conversion was observed with 11β-hydroxysteroids such as cortisol, corticosterone, dexamethasone, and prednisolone. In addition, the crystal structure of BaCYP106A6 was determined at a resolution of 2.8 Å to investigate the configuration of the substrate-binding site and understand substrate preference. This structural characterization and comparison with other bacterial steroid hydroxylase CYPs allowed us to identify a unique Arg295 residue that may serve as the key residue for substrate specificity and regioselectivity in BaCYP106A6. This observation provides valuable background for further protein engineering to design commercially useful CYP steroid hydroxylases with different substrate specificities.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.203-209
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• 2017

The propenyl ether-type monomers which are applicable for cationic photo-polymerization were synthesized by the condensation reaction of mono and di-functional alcohol with allyl bromide. To examine photo-curable reactivity, these monomers were combined with cationic photoinitiator to prepare coating composition. As a result, the initial rate of polymerization of POMB in mono propenyl ether type was 10.2, which was relatively lower than BPOB in di-propenyl ethers type. However, POMB containing 1.5mol% photoinitiator almost quantitatively reacted within 90 seconds. In addition, Sulfonium salt type photo-initiators containing long-alkyl group showed good solubility with monomers and apperaed to have comparatively higher rate of polymerization and conversion ratio when applying DPSA and DPST which have high acidity on all monomers.

• KSBB Journal
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• v.20 no.6
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• pp.458-463
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• 2005

[ $H_2$ ] from CO and water was continuously produced in a trickle bed reactor(TBR) using Citrobacter amalonaticus Y19. When the strain C. was cultivated in a stirred-tank reactor under a chemoheterotrophic and aerobic condition, the high final cell concentration of 13 g/L was obtained at 10 hr. When the culture was switched to an anaerobic condition with the continuous supply of gaseous CO, CO-dependent hydrogenase was fully induced and its hydrogen production activity approached 16 mmol/g cell/hr in 60 hr. The fully induced C. amalonaticus Y19 cells were circulated through a TBR packed with polyurethane foam, and the TBR was operated for more than 20 days for $H_2$ production. As gas retention time decreased or inlet CO partial pressure increased, $H_2$ production rate increased but the conversion from CO to $H_2$ decreased. The maximum $H_2$ production rate obtained was 16 mmol/L/hr at the gas retention time of 25 min and the CO inlet partial pressure of 0.4 atm. The high $H_2$ production rate was attributed to the high cell density in the liquid phase circulating the TBR as well as the high surface area of polyurethane foam used as packing material of the TBR.