Microalgae are promising feedstock for the production of biodiesel and diverse medium- and high-value products such as pigments and polyunsaturated fatty acids. The importance of strain selection adapted to specific environments is important for economical purposes. We characterize here two microalgal strains, isolated from wastewater of shrimp cultivation ponds in Vietnam. Based on the 18S rDNA-ITS region, one strain belongs to the Eustigmatophyceae class and is identical to the Nannochloropsis salina isolate D12 (JX185299.1), while the other is a Chlorophyceae belonging to the Desmodesmus genus, which possesses a S516 group I intron in its 18S rDNA gene. The N. salina strain is a marine and oleaginous microalga (40% of dry weight (DW) at stationary phase) whole oil is rich in saturated fatty acids (around 45% of C16:0) suitable for biodiesel and contains a few percent of eicosapentaenoic acid (C20:5). The Desmodesmus isolate can assimilate acetate and ammonium and is rich in lutein. Its oil contains around 40%–50% α-linolenic acid (C18:3), an essential fatty acid. Since they tolerate various salinities (10% to 35‰), both strains are thus interesting for biodiesel or aquaculture valorization in coastal and tropical climate where water, nutrient, and salinity availability vary greatly depending on the season.
This study has shown for the first time the antimicrobial, antioxidant and cytotoxicity of 3 fractions of acetone extract, including hexane, chloroform and ethyl acetate from flowers of Dipterocarpus intricatus. Antibacterial test using disc diffusion method showed that the chloroform and ethyl acetate fractions inhibited the growth of all the tested bacteria, including Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus and Staphylococcus aureus while the hexane fraction showed the antibacterial activity against B. cereus and S. enteritidis. Antioxidant activity and cancer cell resistance of those extracts were conducted using DPPH and MTT methods respectively. As a result, the DPPH radical scavenging activity of the hexane, chloroform and ethyl acetate fractions were determined with the IC50 values of 0.508, 0.22 and 0.075 mg/mL respectively while the cytotoxicity to HepG2 cell line of those fractions was 163.3 ppm, 106.7 ppm and 459.3 ppm. These results suggested the potential application of these fractions isolated from D. intricatus flowers as the natural antimicrobial, antioxidant and cytotoxic agents for medicine.
The Vietnamese food industry produces a lot of coffee pulp, which is a valuable and abundant source of agricultural by-products. It contains a lot of cellulose, which can be converted into bioethanol. However, coffee pulp needs an extensive pretreatment to reduce the amount of lignin and hemicellulose while retaining the initial cellulose composition. This study compared several pre-hydrolysis and pre-fermentation pretreatment methods which involved H2SO4, NaOH, microwaves, and white rot fungus Phanerochaete chrysosporium. The hemicellulose dropped by 43.8% after the acidic pretreatment, by 47.1% after the alkaline pretreatment, and by 12.8% after the microbial pretreatment. The lignin contents dropped by 4.2, 76.6, and 50.2% after acidic, alkaline, and microbial pretreatment, respectively. The removal of hemicellulose and lignin in the coffee pulp was much more efficient when two or three of the pretreatment methods were combined. The microwave-assisted acid and alkaline pretreatment was the most efficient method: it removed 71.3% of hemicellulose and 79.2% of lignin. The combined method also had the highest amount of reducing sugars and glucose in hydrolysate. Additionally, concentrations of such yeast inhibitors as 5-hydroxymethyl-2-furaldehyde (HMF) and furfural were 2.11 and 3.37 g/L, respectively. The acid pretreatment was effective only in removing hemicellulose while the alkaline pretreatment was effective in lignin removal; the fungal pretreatment had low results for both hemicellulose and lignin removals. Therefore, the combined pretreatment method was found optimal for coffee pulp.
Phlogacanthus cornutus is a rare species and the chemical profiles and the bioactivities of this plant are unknown. In present study, the chemical components of the acetone extract as well as the antioxidant activity of acetone extract and its fractions such as n-hexane, chloroform and ethyl acetate of P. cornutus were firstly reported. A total of 33 constituents were identify in the acetone extract of this plant using Gas Chromatography/Mass Spectrometry assay, in which trans-cinnamic acid (21.26%), neophytadiene (6.36%), linolenic acid (5.86%), dihydroagathic acid (5.71%), n-hexadecanoic acid (5.53%), phytol (4.14%) and cis-cinnamic acid (3.23%) were the major compounds. The acetone extract and its fractions such as n-hexane, chloroform and ethyl acetate of P. cornutus showed DPPH radical scavenging activity with IC50 value of 234.31, 185.95, 758.65 and 458.52 µg/mL respectively.
Camellia seeds are rich in oil and contain fatty acids that offer significant health benefits. This study aimed to characterize C. oleifera seeds and their oil. Physical properties of the seeds, including 1000-seed weight, density, moisture content, specific gravity, and angle of repose, were determined. Camellia seed oil was extracted using the pressing method, and various physicochemical and biological properties of the oil – such as density, color, acid, peroxide, and saponification values, as well as antioxidant and antibacterial activities – were assessed. Pressing the oil at 140oC yielded optimal results, achieving a recovery efficiency of 21.67%. Gas chromatography-mass spectrometry identified seven fatty acid components in the oil, with oleic acid (71.03%) being the most abundant. The antioxidant capacity of the oil was evaluated using a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, yielding an IC50 value of 265.8 mg/ml. However, the oil exhibited no inhibitory effects against four bacterial strains (Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus, and Staphylococcus aureus). These findings highlight the potential of Camellia seed oil in food technology, particularly as an alternative to commercial cooking oils.