Enzyme immobilization offers an innovative approach for reuse, preservation, and optimization of production efficiency and costs in the food and biofuel industries. In this study, amylase enzymes immobilized in Ca-alginate membranes were utilized in the fermentation of traditional sticky rice wine. The morphology and activity of immobilized amylase beads were maintained effectively at a 2% concentration of both carrier material and enzyme solution. After seven days of fermentation, fermentation efficiency reached an ethanol concentration of 55% v/v. The activity of immobilized amylase retained 60% of its activity after four consecutive fermentation cycles. These results suggest that immobilized amylase beads have promising applications in sticky rice wine production, replacing free amylase, which is difficult to recover and reuse.

Dragon fruit-based wine is a value-added product that enhances the value of domestic agricultural products, especially for those facing challenges in raw form export. In this study, Saccharomyces cerevisiae yeast cells were immobilized using the Ca-alginate carrier for assessing the influence of Na-alginate and CaCl2 concentrations on the quality of immobilized Ca-alginate beads during wine fermentation. A repeated fermentation study was conducted to determine the efficiency and stability of immobilized beads in dragon fruit-based wine fermentation. The results indicated that the immobilized Ca-alginate beads exhibited good fermentation efficiency with 3% Na-alginate and 2% CaCl2 concentrations. Moreover, the fermentation efficiency was maintained through at least four fermentation cycles. The immobilized yeast cells contributed to the production of wine with favorable qualities in terms of color and taste, meeting the standards in laboratory-scale TCVN 3215-79. These findings underscore the potential of cell immobilization technology using Ca-alginate carriers in the fermentation process of dragon fruit- based wine. This technology significantly enhances the value and diversifies the range of Vietnamese agricultural products, mainly dragon fruit

Ficus hispida L.f. (FH) is among the widely cultivated tree species in Asian regions. The aim of this work was to determine phenolic and flavonoid contents, antioxidant, in vitro anti-inflammatory activities of FH extracts prepared with methanol (ME), ethanol (ET) and ethyl acetate (EA). The extract obtained from ethyl acetate contained the highest total phenolic and flavonoid contents (92.75 +/- 5.14 mg GAE/g and 5.67 +/- 0.65 mg QE/g), followed by ME and ET. The capacity to scavenge ABTS free radical of the extracts followed the order: EA > ME > ET while their DPPH activity differed insignificantly. The inhibitory effect of EA and ME (IC¬50 = 362.84 +/- 29.05 and 386.95 +/- 11.10 ug/mL, respectively) were higher than that of ET. Correlation analysis showed a high positive correlation between total phenolic content and ABTS activity. The findings of the study would be useful for development of new nature-derived agents for prevention and treatment of diseases.

Coffee is among the favorite drinks in Vietnam and many other countries. Production and consumption of coffee have released a huge amount of spent coffee ground. This study aimed to determine phenolic acids and fatty acids of spent coffee grounds collected in Ho Chi Minh city and how phenolic acid profile was affected by different environmentally friendly extractants. The results showed that average level of chlorogenic acid in ethanol/water extracts (840.4 779.9 ug/g) was significantly higher compared to water extracts (300.0 ug/g). Furthermore, the average total level of phenolic acids in ethanol/water extracts (1215.3 ug/g dry weight) was greater than that in the water extracts (779.9 ug/g dry weight). This indicated that ethanol/water outperformed water in regard to extraction of phenolic acids in the spent coffee grounds. Oil extracted from the spent coffee grounds was rich in linoleic acid (61 ug/g) and palmitic acid (47 ug/g). The findings of our study showed that the spent coffee grounds originating in Vietnam are a good source of phenolic acids and polyunsaturated fatty acids that could be utilized for food and nutraceutical production.

Declining supplies of fossil fuels, increasing population, global industrialization and demand for transportation fuels has triggered an increase in the demand for renewable energy sources. To address such problems most of the green research in the recent years has focused on the development of bioethanol (23 MJ/L) as a substitute to conventional gasoline (34.3 MJ/L) based fuels owing to the similarity in energy density values in addition to several other advantages (American Council on renewable energy, 2010). Second-generation biofuels are derived from lignocellulosic biomass or woody crops, mostly coming from agricultural residues. Extraction of fuel from such biomass is difficult because of their recalcitrant nature (corn stover, rice straw, wheat straw, sugar cane and sweet sorghum). Lignocellulosic fuel has the potential to solve several problems (food competing with fuel) that are currently associated with first generation biofuels. Moreover, lignocellulosic fuels can supply a larger proportion of the global fuel leading to sustainability at lower cost, and with greater environmental benefits (Liz Marsall, 2009). The production of ethanol from the complex sugars in leaves and stalks is a promising strategy to radically broaden the range of possible ethanol feedstock. Keywords: lignocellulose, bioethanol, biomass, pretreatment, hydrolysis, fermentation.

Lignocellulosic biomass is one of the largest carbohydrate sources and has huge potential for biofuels production. However, the problem with lignocellulosic feedstock is that it has useful sugars locked in by lignin, hemicellulose, and cellulose. Some kind of pretreatment; therefore is needed to make carbohydrate accessible which later can be fermented to produce ethanol. The results from this research indicated that the yields of glucan (93%) and xylan (82.8%) were improved by using milling combined with ELLA pretreatment. The optimal enzymatic hydrolysis efficiencies were obtained under 10 min for ball milling time, pretreatment at 1 h, temperature at 150°C, S/L = 0.5 and ammonia loading at 0.25 g-NH3/g-biomass. This method reduced the pretreatment time and short milling time and thus has potential of reducing the energy consumption and promising the application in the large scale. Keywords: corn stover, milling pretreatments, ammonia pretreatment, bioethanol.