Effect of Angelica gigas Nakai extract on hepatic damage in rats

Purpose: To determine the antioxidant and hepatoprotective effects of decursin and decursinol angelate (D/DA) isolated from Angelica gigas Nakai (AGN).Methods: The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of D/DA was assessed in a rat model using blood tests, western blotting, and histopathological analyses to identify the pharmaceutical effects of D/DA on liver enzymes and liver morphology.Results: The DPPH scavenging activity of D/DA was 47.11 μg/mL. Administration of D/DA to carbon tetrachloride (CCl4)-treated rats led to a decrease (13.59 %) in the total liver mass of control rats. Decursin and decursinol angelate also lowered the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), but increased the concentrations of antioxidant enzymes in the liver, including catalase (CAT) and glutathione peroxidase (GPx). Histological examination revealed that D/DA also reduced hepatocellular damage in the rats.Conclusion: D/DA from AGN has significant anti-hepatotoxic and antioxidant activities, and thus, is a potential herbal drug for treating liver damage. Keywords: Decursin, Decursinol angelate, Antihepatotoxicity, Antioxidant, Angelica gigas Naka

Optimization of isoprene production using a metabolically engineered Escherichia Coli

The volatile C5 hydrocarbon, isoprene is an important platform chemical, which has been used in the manufacture of synthetic rubber for tires and also has the potential for various other applications such as elastomers and adhesives. Moreover, isoprene is convertible to biofuel blend stocks such as C10 gasoline, C15 diesel, and jet fuels because of its higher energy content than other biofuels. Although isoprene is currently derived from petroleum, its sustainable supply has been suffered from price fluctuation of crude oil, high refining cost and energy consumption, and low recovery yield of pure isoprene. As an alternative, the biologically produced isoprene (bio-isoprene) has been developed rapidly for the last decade. Bio-isoprene is synthesized from dimethylallyl diphosphate (DMAPP), which is derived from mevalonate (MVA) pathway or the methylerythritol phosphate (MEP) pathway, by isoprene synthase. In this study, metabolic engineering for enhanced production of bio-isoprene was performed by deletion of relevant genes and optimization of culture condition. In comparison of isoprene production between E.coli DH5α and MG1655, lower isoprene production was observed in MG1655. The lower isoprene production in E. coli MG1655 was ascribed to the presence of recA gene which is absent in the DH5α strain. The deletion of recA gene in E.coli MG1655 allows higher isoprene production than E. coli DH5α. Moreover, the optimized expression of isoprene synthesis pathway with 0.03mM IPTG induction enhanced the isoprene production up to 2,850 mg/L. Overall, isoprene production through the optimization was improved by 28.5-fold compared to the initial production of MG1655 strain. Please click Additional Files below to see the full abstract

Improvement of retinoids production in recombinant E. coli using glyoxylic acid

Isoprenoids are the most chemically diverse compounds found in nature. They are present in all organisms and have essential roles in membrane structure, redox chemistry, reproductive cycles, growth regulation, signal transduction and defense mechanisms. In spite of their diversity of functions and structures, all isoprenoids are derived from the common building blocks of isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP). Optimization of IPP synthesis pathway is of benefit to mass production of various isoprenoids. There are two pathways of 2-C-Methyl-D-erythritol-4-phosphate (MEP) and mevalonate (MVA) for IPP synthesis. Prokaryotes including E. coli generally use MEP pathway whereas MVA pathway is used in eukaryotes. To improve isoprenoid production, it was performed the deletion of genes in E. coli, which are involved in both formation of fermentation by-products such as organic acids and alcohols, and consumption of precursors of MEP and MVA pathways, pyruvate and acetyl-CoA. As a result, we were able to develop a strain with improved fermentation productivity and carbon source utilization efficiency, the mutant strain was called AceCo. Higher lycopene production was achieved in the AceCo strain compared to the wild type MG1655 strain due to no formation of the inhibitory by-products. However, retinoids production of AceCo strain decreased to a half of that of MG1655 strain. Please click Additional Files below to see the full abstract

CO-COMBUSTION OF KOREAN ANTHRACITE WITH VARIOUS FUELS IN A COMMERCIAL CIRCULATING FLUIDIZED BED BOILER

The effect of co-combustion of various fuels such as bituminous coal, imported anthracite, RDF and wood pellet with Korean anthracite on the combustion and environmental performance was observed in the commercial CFB boiler. The temperatures in the furnace and cyclones exits decreased with increasing the cocombustion ratio of the bituminous coal, which could achieve more stable operation of the CFB boiler. During Co-combustion of the RDF and wood pellets, the temperature of the furnace exit increased slightly with due to volatiles re-combustion which could restrict to increase the co-combustion ratio of the RDF and wood pellets in the CFB boiler. It was limited for the electrostatic precipitator (EP) to maintain the stable operation above 5% of the RDF co-combustion ratio according to decrease of the output voltages of the EP collecting plate. High content of CaO in the RDF and the wood pellet made the required limestone flow rates decrease. The emissions NOx, HCl and dioxin during co-combustion of the RDF and wood pellets did not change appreciably when compared with firing only Korean anthracite, which were also low enough to meet Korean regulation limits. On the other hand, chlorine content in the ashes emitted from the boiler increased gradually with increasing the RDF co-combustion ratio because of absorption by limestone. The co-combustion of various fuels with Korean anthracite in the commercial CFB boiler was found to be of great use up to a certain co-combustion ratio of each fuel without the technical and environmental problems

Sequential whole cell conversion process for production of D-psicose and D- mannitol from D-fructose

Rare sugars, which exist only limited quantities naturally, have received considerable attention because of its various specific nutritional and biological functions. Likewise, D-psicose (D-ribo-2-hexulose or D-allulose), a C-3 epimer of D-fructose, has many uses which include reducing intra-abdominal fat accumulation, protecting pancreas beta-islets and improving insulin sensitivity. Especially, D-psicose has only 0.3% calories compared to sucrose, while it has 70% relative sweetness. Additionally, in 2012, D-psicose was approved as a food additive and designated as Generally Recognized As Safe (GRAS) by Food and Drug Administration (FDA). Despite such abundant advantages, there is no economical way of mass production of D-psicose. Recently, biological production of D-psicose from D-fructose using D-psicose 3-epimerase (DPE) has been developed. However, the conversion yield is below 30%, which causes an undesirable increase of purification cost because of the similar solubility of D-psicose and D-fructose. Thus, we addressed the problem by converting the residual fructose, after the reaction of D-psicose production, to D-mannitol, which has a low solubility. The sequential whole cell conversion reactions for D-psicose and D-mannitol allow a convenient and economic purification of both products. This work was supported by a grant from the Next-Generation BioGreen 21 Program (SSAC, grant#: PJ01106201), RDA, Korea. Reference 1) Carsten Bäumchen & Stephanie Bringer-Meyer (2007), Expression of glf Z.m. increases D-mannitol formation in whole cell biotransformation with resting cells of Corynebacterium glutamicum, Appl Microbiol Biotechnol 76(3):545–52. 2) Ortiz, M. E., Bleckwedel, J., Raya, R. R., & Mozzi, F. (2013). Biotechnological and in situ food production of polyols by lactic acid bacteria, Appl Microbiol Biotechnol 97:4713-4726 3) Park, Y., Oh, E. J., Jo, J., Jin, Y., & Seo, J. (2016). Recent advances in biological production of sugar alcohols. Curr Opin Biotechnol 37:105–113