http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/1 Tất cả chứa ở đây Sun, 06 Sep 2026 03:15:13 GMT 2026-09-06T03:15:13Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21832 Title: Evaluation of bioactivities and formulation of face mask from Sargassum sp. extract. Authors: Dang, Diem Hong; Phan, Bao Vy; Ngo, Thi Hoai Thu; Tran, Xuan Khoi; Nguyen, Cam Ha; Luu, Thi Tam Abstract: Brown seaweeds, particularly Sargassum genus, contain large amount of polysaccharides, such as alginate and fucoidan, which are widely applied to related health care approaches. Obviously, this genus is a potential alternative resource for cosmetic industry with its extract gained a great deal of biochemical composition and bioactivity. This study showed that the protein, lipid, total carbohydrate, chlorophyll and carotenoid contents of Sargassum sp. which collected in Khanh Hoa, Vietnam were 10.45 ± 1.15%, 1.90 ± 0.12%, 50.55 ± 1.05%, 0.25 ± 0.03 mg/g and 0.104 ± 0.001 mg/g of dry weight (DW), respectively. The hot water extract of Sargassum sp. showed high free radical scavenging activity (85.82 ± 1.89% at 50 mg/mL), antibacterial activity with the range of minimal inhibitory concentrations (MIC) from 25–100 mg/mL and tyrosinase inhibitory activity (16.19 ± 1.05%, 22.94 ± 1.23%, 104.16 ± 4.15% at concentrations of 50, 100 and 200 mg/mL). The formula of face mask from 10% of Sargassum sp. extract gained antioxidant and tyrosinase inhibitory activity with 61.67 ± 0.06% and 29.064 ± 0.06%, respectively. This product was also evaluated for the physical properties included organoleptic (brown color with specific odor), pH, homogeneity, spread ability and irritation test. The bacterial criteria, heavy metal levels of face mask were also recognized to evaluate for safety of human health following Ministry of Health standard. Mon, 01 Jan 2018 00:00:00 GMT http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21832 2018-01-01T00:00:00Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21831 Title: Characterization of bioflocculant-producing bacteria isolated in Vietnam and its use for harvesting indigenous microalgae. Authors: Le, Thi Anh Tu Abstract: Bioflocculation producing bacteria isolated from soil and sediment in Da Lat City, Lam Dong Province, Vietnam, were characterized. Four bacterial strains that had high flocculation activity were Flavobacterium granuli CL, Hydrogenophaga pseudoflava DA, Alcaligenes cupidus PT2, Bacillus mucilaginosus PT3, with the flocculation efficiency of 91.37%, 83.12%, 76.92%, and 75.81%, respectively at 22°C, pH 10, the initial algae concentration (optical density at 690 nm) of 1.25, and grown in media containing glucose as the carbon source. The bioflocculation efficiency was depended on the pH, carbon sources, the initial algae concentrations, bacteria strains, and the inital bioflocculant-producing bacteria concentrations. The temperature lightly affected the bioflocculation, no noticeable behavioral or activity changes were observed in mice that were orally administrated with four bacterial strains, and no treatment-related illness or death occurred after 72 hours. In general, the bioflocculation process is easy to operate, cost-effective, environment-friendly and therefore, it can be applied for industrial processing of microalgae. Mon, 01 Jan 2018 00:00:00 GMT http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21831 2018-01-01T00:00:00Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21830 Title: Expression of a novel gene encoding protease inhibitor from metagenome of sponge in Vietnam. Authors: Tran, Thi Hong; Ton, That Huu Dat; Nguyen, Phuong Hoa; Pham, Viet Cuong; Nguyen, Thi Kim Cuc Abstract: Marine sponge is known as a “gold mine” of natural products from marine environment. Many novel bioactive compounds have been isolated from marine sponges and sponge-associated microorganisms such as antibiotics, anti-cancer compounds, protease inhibitors, etc. In this study, we selected a gene encoding protease inhibitor from metagenome of a sponge collected in Da Nang to express in Escherichia coli BL21(DE3). The gene PI-DN9 encoding protease inhibitor (1.3 kb) was cut off cloning vector pUC57/PI-DN9 containing gene PI-DN9 and inserted into expression vector pET32a(+), the recombinant vector pET32a(+)/PI-DN9 then was transformed and expressed in the E. coli strain BL21(DE3). Results showed that recombinant protein (50 kDa) was expressed successfully at 25°C, 1 mM of IPTG in 5 hours. The recombinant protein was purified using Ni-NTA affinity chromatography column. Western blot assay and bioactive assay showed good activity of the purified protein. Mon, 01 Jan 2018 00:00:00 GMT http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21830 2018-01-01T00:00:00Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21828 Title: Molecular taxonomy of some sponges (Demospongiae) using ribosomal (18s rrna) and partial mitochondrial (coi) genes. Authors: Ton, That Huu Dat; Nguyen, Thi Kim Cuc; Pham, Viet Cuong Abstract: Sponges, the most ancient multicellular metazoan, were widely distributed across habitats. Vietnam is known to possess a high biodiversity of sponges, however, they are mostly identified based on morphological characteristics and lack the molecular data. In the current study, the phylogenetic relationship of some sponges (Demospongiae) in Vietnam was constructed using two independent markers (COI and 18S rRNA). In this paper the individual markers (COI and 18S rRNA) were successfully used to identify some sponge taxa at the species level. The obtained results showed the congruence of molecular taxonomy using two independent markers. However, our study showed that a combination of the two markers provided more information and supported better for sponge identification. At order level, the COI tree and 18S rRNA tree also recovered the same clades, indicating the congruence of COI and 18S rRNA genes in sponge classification. However, branching order of the clades in COI tree was weakly supported and slightly different from those in 18S rRNA tree. Mon, 01 Jan 2018 00:00:00 GMT http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21828 2018-01-01T00:00:00Z http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21827 Title: Identification of nutrient composition of some isolated microalgae from mangroves of Xuan Thuy national park. Authors: Le, Xuan Tuan; Tran, Thi Minh Hang Abstract: Microalgae species, such as Amphiprora alata, Chaetoceros muelleri, Nannochloropsis oculata, Navicula tuscula and Chlorella vulgaris from mangrove area of Xuan Thuy National Park are usually used as food sources for fishes, shrimps and bivalves and very environment friendly. The samples of these microalgae were enriched, isolated and purified in F/2 medium with salinity of 20%. The purifed colonies were cultured in media with different salinity in 14 days to find out the most optimal medium for the best growth as well as the stage yielding maximum living mass. These microalgae were then cultured in their optimal media at salinity of 25% until they reached their maximum living mass stage. They were cultivated and analyzed of their fatty acid, protein carbonhydrate components and percentages. The research has identified 24 fatty acids in 5 phytoplankton species. Unsaturated fatty acids components of Chaetoceros muelleri, Nannochloropsis oculata are the highest (76,35% and 71,17%), and fatty acid components of are medium Chlorella vulgaris and Amphiprora alata (59,24% and 52,21%), meanwhile, Navicula tuscula has 29.56% of unsaturated fatty acids. Amphiprora alata and Chlorella vulgaris have protein content of 8.1g per 100g dry weight and 4.44g per 100g dry weight accordingly. Carbohydrate content of Nannochloropsis oculata and Navicula tuscula are 11.8g per 100g dry weight and 5.47g per 100g dry weight, respectively. Mon, 01 Jan 2018 00:00:00 GMT http://tvhdh.vnio.org.vn:8080/dspace/handle/123456789/21827 2018-01-01T00:00:00Z