• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1671-1682
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• 2018

Alginate lyases (endo and exo-lyases) are required for the degradation of alginate into its constituting monomers. Efficient bioethanol production and extraction of bioactives from brown algae requires intensive use of these enzymes. Nonetheless, there are few commercial alginate lyase preparations, and their costs make them unsuitable for large scale experiments. A recombinant expression protocol has been developed in this study for producing seven endo-lyases and three exo-lyases as soluble and highly active preparations. Saccharification of alginate using 21 different endo/exo-lyase combinations shows that there is complementary enzymatic activity between some of the endo/exo pairs. This is probably due to favorable matching of their substrate biases for the different glycosidic bonds in the alginate molecule. Therefore, selection of enzymes for the best saccharification results for a given biomass should be based on screens comprising both types of lyases. Additionally, different incubation temperatures, enzyme load ratios, and enzyme loading strategies were assessed using the best four enzyme combinations for treating Macrocystis pyrifera biomass. It was shown that $30^{\circ}C$ with a 1:3 endo/exo loading ratio was suitable for all four combinations. Moreover, simultaneous loading of endo-and exo-lyases at the beginning of the reaction allowed maximum alginate saccharification in half the time than when the exo-lyases were added sequentially.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.453-460
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• 2018

Owing to rising oil prices and anthropogenic global warming, focused attempts are being made toward production of industrially important compounds by using renewable biomass. In this context, algal biomass as third-generation biomass is important because it doesn't compatible with food resource, has high yield, and helps abate greenhouse gases. Here, we investigate whether Undaria has the highest sugar content, which would make it the most suitable biomass for lactic acid production among the four algal biomasses tested. For effective pretreatment of Undaria, the response surface methodology was used. The amount of solid loaded and catalyst concentration were related to the extraction rate of total sugar. Lactic acid was produced by pretreatment of Undaria by using four Lactobacilli, and L. alimentarius and L. brevis were found to be suitable for lactic acid production.

• Journal of Nutrition and Health
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• v.51 no.6
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• pp.507-514
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• 2018

Purpose: Sargassum horneri (S. horneri) is a species of brown macroalgae that is common along the coast of Japan and Korea. The present study investigated the immuno-modulatory effects of different types of S. horneri extracts in RAW264.7 macrophages. Methods: S. horneri was extracted by three different methods, hot water extraction, 50% ethanol extraction, and supercritical fluid extraction. Cell viability was then measured by MTT assay, while the production levels of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin-6 (IL-6), and nitric oxide (NO) were measured by enzyme-linked immunosorbent assay and Griess assay, respectively. The expression and activation levels of inducible NO synthase (iNOS), mitogen-activated protein kinase (MAPK) and nuclear factor ${\kappa}B$ ($NF-{\kappa}B$) were examined by western blot analysis. Results: The three different S. horneri extracts were nontoxic against RAW 264.7 cells up to $50{\mu}g/mL$, among which treatment with hot water extract (HWE) of S. horneri significantly enhanced the production of TNF-${\alpha}$, IL-6, and NO in a dose-dependent manner. Hot water extract of S. horneri also increased the expression level of iNOS, suggesting that up-regulation of iNOS expression by HWE of S. horneri was responsible for the induction of NO production. In addition, treatment of RAW 264.7 macrophages with HWE of S. horneri increased the phosphorylation levels of ERK, p38 and JNK. Furthermore, the activation and subsequent nuclear translocation of $NF-{\kappa}B$ was enhanced upon treatment with HWE of S. horneri, indicating that HWE of S. horneri activates macrophages to secrete TNF-${\alpha}$, IL-6 and NO and induces iNOS expression via activation of the $NF-{\kappa}B$ and MAPKs signaling pathways. Conclusion: Taken together, these findings suggest that HWE of S. horneri possesses potential as a functional food with immunomodulatory activity.