Earticle

There has been a growing attention on PDLA (poly D-lactic acid) since stereocomplex PLA, a kind of polymer alloy between PLLA and PDLA was known much thermally stable compared PLLA. Superior characteristics of stereocomplex PLA result in the elevated demand for D-lactic acid. Although many research works have been reported for L-lactic acid production especially food industry, however there are relatively few research works for D-lactic acid production since D-lactic acid cannot find any applications in food industry. Most imminent issue for D-lactic acid is the economic production process that requires low cost medium, efficient lactic acid producing microorganism and finally large scale-up design. In this review, current status of D-lactic acid production process will be summarized and discussed for the further improvement of D-lactic acid production process.

Bioactive peptides (BAP) showed excellent cosmetic activity than bio-materials such as caffeic acid (CA), gallic acid (GA), and nicotinic acid (NA). Caffeoyl tripeptide-1 (CT-1) is a BAP that is stabilized with Gly-His-Lys (GHK) tripeptide and CA by using Fmoc solid phase peptide synthesis. Digalloyl tetrapeptide-19 (DT-19) is stabilized by combining Lys-Glu-Cys-Gly with GA and nicotinoyl tripeptide-1 (NT-1) is synthesized by GHK and NA. According to experiments, CT-1 has an excellent anti-oxidant function even with a very small amount of 10 ppm CT-1. DT-19’ tyrosinase inhibition activity has the better effect of about 28.57% in 0.01% and 33.33% in 0.005% of concentration and about 7.89% in 0.001% concentration than vitamin-C. In addition, NT-1 is safer than the NA. Almost BAPs like pal-KTTKS, acetyl hexapeptide, and copper tripeptide-1 have the anti-wrinkle effect while DT-19 and NT-1 are applicable for potential BAPs focused on the whitening effect. The three kinds of BAPs like CT-1, DT-19, and NT-1 consisting of amino acids are safe to the skin, and have more excellent stability than bio-materials which are found to be unstable and cause skin irritation. Due to the high biological activity of BAP in the field of skin care, its utilization will increase constantly.

Psolarea corylifolia extract that contains bakuchiol is known to have anti-microbial, anti-inflammatory and anti-scarring effects. In this study, a vesicles such as liposome, niosome, and transfersome were produced to encapsulate P. corylifolia extract and measured their stability and physiochemical property. The skin permeation and partitioning of P. corylifolia extract in the vesicles were elucidated in nude mouse skin by using Franz diffusion cells after topical application for 24 h. After storage at 25, 40, 70℃, and light, the stability of bakuchiol incorporated into the vesicles was maintained for 30 days. The optimal concentration of P. corylifolia extract entrapped into the vesicles was found to be 5~10%. From the physicochemical studies, after storage at 4, 25, and 40℃, the viscosity and particle size of the vesicles remained in 30~80 cP and the nanosize range for 6 months, respectively. From the permeation experiments, niosome showed a higher amount of bakuchiol permeated through the mouse skin compared to liposome and transfersome after 24 h. From these results, niosome and transfersome could be a good bioavailability enhancement system (BAES) for P. corylifolia extract to improve the skin permeation and stability.

The occurrence of dental caries is mainly associated with oral pathogens, especially cariogenic Streptococcus mutans. The aim of this study was to isolate and characterize lactic acid bacterium showing inhibitory activity against cariogenic Streptococcus mutans. As results, an isolate with strong inhibitory activity was obtained from Kimchi and it was identified as Lactobacillus sakei by API and 16S rRNA gene analyses. This strain secreted an inhibitory compound in cell growth medium and the activity of the compound was completely disappeared by proteinase K revealing the fact that the compound is proteinous substance, bacteriocin. Optimal culture condition for bacteriocin production by Lb. sakei K-7 was at pH 7.5 and 37℃ for 18 h. Oral administration of this isolate may give anticariogenic and probiotic effects on hosts.

In our previous study, we isolated and characterized a 1-deoxynojirimycin (DNJ)-producing bacterium, Bacillus subtilis MORI, from chungkookjang, a Korean traditional food. B. subtilis MORI was subjected to γ-irradiation and the resulting bacteria were screened for increased DNJ production. A mutant was identified that produced 7.6 times more DNJ and named B. subtilis MORI 3K-85. In this study, the protein profiles of both strains were compared by one-dimensional and two-dimensional gel electrophoresis (1-DE and 2-DE, respectively) under both native and denaturing conditions. The 1-DE native-PAGE and 1-DE SDS-PAGE analyses identified 5 and 7 bands, respectively, that were found at higher concentrations in B. subtilisMORI 3K-85 than in B. subtilis MORI. Similarly, 2-DE analyses identified 20 protein spots which were found at higher concentrations in B. subtilis MORI 3K-85. The peptide mass profiles of these 20 proteins were analyzed by MALDI-TOF and compared with peptide sequences of B. subtilis and B. amyloliquefaciens in the MASCOT database. This screening suggested that three dehydrogenases, an aldolase, a synthetase, an isomerase, a reductase, and a peroxidase are elevated in B. subtilis MORI 3K-85. Based on this data, one or more of the elevated 8 enzymes might be related to the DNJ biosynthetic pathway.

The objective of this study was to reduce negative elements such as volatile organic compounds (VOCs) from fulvic acid using supercritical carbon dioxide (SCO2) and to measure concentration and chromaticity of fulvic acid before and after treatment of SCO2. Fulvic acid was treated at different experimental conditions; pressures of 100, 120 and 150 bar at 40℃ for 2 h. The composition of VOCs from fulvic acid was evaluated by GC-MS analysis, and the concentration was quantitatively analyzed using UV-spectrometer from fulvic acid at different experimental conditions. Also, the chromaticity of fulvic acid was evaluated using spectrophotometer. Though concentration and chromaticity of fulvic acid were not nearly changed, the VOCs from fulvic acid was remarkably decreased at 150 bar, 40℃ and 2 h. Reduction of VOCs through the SCO2 is expected to contribute to quality improvement of fulvic acid.

Whey based medium was optimized for the production of viable Lactobacillus crispatus KLB 46 isolated from the vagina of Korean women. Among the various nitrogen sources such as yeast extract, beef extract, and proteose peptone no. 3 supplemented to whey, beef extract showed the highest viable cell production. The addition of Tween 80 to the whey based medium increased viable cell concentration. As beef extract supplementation is not economically attractive, corn steep liquor was added as a supplementary nitrogen sources. When corn steep liquor was supplied with beef extract with the ratio 5：1, the viable cell count was 3.11 × 109 CFU/mL. Also, the addition of mineral salts containing sodium acetate (5 g/L), potassium phosphate dibasic (2 g/L), magnesium sulfate (0.1 g/L) and manganese sulfate (0.05 g/L) to the whey medium increased viable cell count further (5.00 × 109 CFU/mL).

The aim of this study was to develop a new natural preservative system to improve the weak points of natural polyhydric alcohols together with the efficiency of natural plants as a preservative. Polyhydric alcohols (glyceryl caprylate and ethylhexylglycerin) and antimicrobial plants (S. radix, A. nilotica and C. reticulata) were tested using the disc diffusion method and minimum inhibitory concentration (MIC) method for their antimicrobial activity against the common poultry pathogens, respectively. A study of the preservative efficacy of the cosmetic formulations containing the optimized preservative system demonstrated sufficient preservative efficacy against bacteria and eukaryotic test microbes. These results suggest that the natural preservative system including polyhydric alcohol extracts containing natural plants could be incorporated in cosmetic formulations.

The research was purposed production of oligosaccharide from alginate hydrolysis the main composition in cell walls of sea weed. We was isolated 252 strains from sea water and mud flat, the highest alginate lyase activity was selected, and identified as Sanguibacter keddieii NC9 by 16S rDNA sequence analysis. In this study was select the sodium alginate concentration, pH, temperature for the production of alginate lyase activity. Alginate lyase activity was confirmed from plate assay with 10% cetylpyridinium chloride. The optimum culture conditions for the production of alginate lyase were sodium alginate 10 g/L, peptone 5 g/L, 40℃, pH 9 and 36 hours incubation time. Sanguibacter keddieii NC9, its alginate lyase would be useful for the production of bioenergy and biofunctional oligosaccharides from sea weed.

Bacterial antibiotic resistance is a real and growing problem for both Gram positive and Gram negative bacterial pathogens in the hospital setting. Among Gram negative bacteria, the ubiquitous bacterium Pseudomonas aeruginosa is a particular concern in immunocompromised and burn patients. The present study evaluated antibacterial activity and efficacy of a Korean herbal medicine against eight multi-drug resistant clinical isolates of P. aeruginosa (0225, 0254, 0347, 0826, 1113, 1378, 1731, and 2492) isolated at Daegu Catholic University Hospital. Methanol extracts of Galla rhois (5 and 10 mg/mL) displayed inhibition diameters for isolate 2492 of 10 and 12 mm, respectively, in a conventional disc diffusion assay. In seven kinds of Korean herbal medicines, increased inhibitory power of Lonicera japonica, Gardenia jasminoides, Galla rhois, and Scultellaria baicalensis was evident with the fermentation of six kinds of lactic acid bacteria. Three lactic acid bacteria (Lactobacillus plantarum subsp. plantarum KCTC 3108, L. casei KCTC 3109, and L. fermentum KCTC 3112) were identified as excellent strains for the production of antibacterial materials. In the six Korean herbal medicine extracts, strong inhibitory activity of fermented Forsythia suspensa, Glycyrrhizae radix, Lycium chinense, Platycodon grum, and Schizandra chinensis with five kinds of lactic acid bacteria was evident for seven multi-drug resistant P. aeruginosa isolates.

A novel agar-degrading bacterium mbrc-1 was isolated from seashore of Kyungpo at Gangwon province and cultured in marine broth 2216 medium. Isolated bacterium mbrc-1 was named as Flammeovirga sp. mbrc-1 based on the 16S rDNA sequence. Its agarase showed maximum activity of 923 units/L at pH 7.0 and 45℃ and sustained 90% remaining activity after exposed to 45℃ for 2 hours. The enzyme hydrolyzed agarose to yield neoagarohexaose (18.5%), neoagarotetraose (38%) and neoagarobiose (43.5%), indicating that the enzyme is β-agarase. Thus, isolated bacterium and its β-agarase would be useful for the industrial production of neoagarotetraose and neoagarobiose.

It has been known that Δ5-desaturase (TAD5) in the biosynthetic pathway of long chain polyunsaturated fatty acids of Thraustochytrium aureumis responsible for the conversion of di-homo-γ-linolenic acid (C20：4) into arachidonic acid (C20：4). The genetic sequence analysis on TAD5 of Thraustochytrium aureum ATCC34304 used in this study showed that it has two amino acid changes when compared to that of Thraustochytrium aureum TAD5 first reported in 2003. Accordingly, Thraustochytrium aureum ATCC34304 TAD5 was named TAD5_1. TAD5_1-inserted methylotropic Pichia pastoris was prepared and then cultured with a precursor fatty acid, di-homo-γ-linolenic acid. GC analysis confirmed that a certain amount of the precursor fatty acid was converted into arachidonic acid. In this study, not only a recombinant Pichia pastoris with the typical activity of Δ5-desaturase which plays an essential role in the biosynthesis of LCPUFAs was successfully made but also the preparationpotential of a recombinant Pichia pastoris strain which may synthesize eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that are important in maintaining and improving human’ brain function was proposed.

In this study, we carried out the development of high performance photobioreactor, which can be used to develop the biological CO2 fixation technology as well as the renewable biofuels, the microalgae Botryococcus braunii. When B. Braunii was cultured in Anti-biofouling photobioreator, growth rate of it showed about 3 times higher than that of bubble column photobioreactor at the same conditions. In case of photobioreactor without bead, after 3 days culture time, biofouling occur rapidly in wall of the photobioreactor. However, with bead 5% (V/V), biofouling do not occur all experimental days.

Reduction of 3-chloro-4-fluoropropiophenone by Saccharomyces cerevisiae as a whole cell biocatalyst was optimized. Effects of glucose, S. cerevisiae and 3-chloro-4-fluoropropiophenone concentrations on conversion of reduction reaction was investigated. Optimum concentrations of glucose, S. cerevisiae and 3-chloro-4-fluoropropiophenone were 100, 40 and 20 g/L, respectively. At optimum condition, 100% of conversion was achieved in 12 hours of reaction.