查看更多>>摘要：In this study, it was found that soluble polysaccharides (SPs) from rice straw were conjugated with high levels of phenolic compounds. A gradient ethanol precipitation method was used to separate conjugates with different phenolic compound components. These conjugates were mainly composed of disaccharides or trisaccharides and phenolic acids that were mainly p-coumaric acid, ferulic acid, vanillic acid, and vanillin. SPs with more conjugates exhibited better effects on Saccharomyces cerevisiae and ethanol fermentation. The change in the proportion of conjugates in SPs significantly affected the accumulation of intracellular trehalose and glycerol content, indicating the effect of the conjugates on intracellular osmotic stress. Moreover, SPs with more conjugates generated lower intracellular hydrogen peroxide (H2O2) levels. Thus, oligosaccharide and phenolic compound conjugates in SPs promoted yeast growth and ethanol fermentation. For instance, OD value reached 9.4, which was 1.3 times higher than the control group, and ethanol content at 36 h was 36.5 g/L, which was 1.3 times higher than the control. Osmotic pressure alleviation and lowered intracellular H2O2 levels by conjugates are key mechanisms of the SPs during yeast growth and ethanol fermentation.
查看更多>>摘要：In recent years, there has been increasing interest in the immobilization of plant growth-regulating microorganisms in various carriers, showing different degrees of effectiveness. Among the carriers, polymeric materials, including alginate-based, have attracted considerable attention. This review aims to provide an overview of research related to matrix selection for the effective encapsulation of microorganisms. To regulate the network properties, particular focus was given to biopolymeric structures, including alginate and various fillers. Searches were conducted on October 30, 2021 in the Scopus and Web of Science databases. A total of 421 publications were collected; 43 items (from 2011 to 2021) were included for further study. Basing on the full-text analysis, the formulation of the most favorable matrix for high microbial survival and controlled release in the soil environment was identified. The most commonly used encapsulation matrix parameters were concentration of sodium alginate 1-3%, crosslinking agent CaCl2 1-2%, the effect of additives is highly dependable on the type of microorganism and the desired properties of the beads. Additives such as starch, bentonite, gelatin are generally utilized for structure changes, increase of survival, biodegradation rate, as well as porosity. The positive effect of bacterial encapsulation was evaluated based on the impact on the plant's growth parameters such as shoot and roots length (growth be up to 100%), colonization rate (approximately 80%). This literature review presents the state-of-the-art on immobilization parameters, selection of alginate matrix components, encapsulation efficiency, methods for the physicochemical analysis of hydrogel capsules, and techniques for testing the efficacy of applied formulations on plants. A protocol for matrix selection and tests necessary to verify inoculant efficacy was proposed, which may become part of future biotechnology trends.
查看更多>>摘要：Vector control remains the most effective approach to prevent dengue, chikungunya and Zika arboviruses transmission. Conventional insecticides have historically failed to control the Aedes aegypti mosquito due to acquired resistance, environmental impact and toxicity. This study evaluated the potential of garlic oil as a biopesticide against the eggs, larvae, pupae and adult forms of Ae. aegypti, in accordance with the World Health Organization recommendations. The larvicidal and pupicidal LC50 values were 1.0 ppm and 20.3 ppm after 72 h, respectively. The oil maintained its activity in simulated field trials, killing all larvae and pupae at the concentrations tested. At 100 ppm, garlic oil inhibited 59.6 +/- 10.6% egg hatching. Toxicity against the adult form was observed as was its potent spatial repellency. Garlic oils composed of different diallyl polysulfide ratios did not significantly impact insecticidal activity although the garlic oil polysulfide mixtures were more potent than the isolated polysulfides. The ovicidal, larvicidal, pupicidal, adulticidal and repellent assays showed the broad activity of garlic oil against Ae. aegypti. These results, together with the activity in simulated field trials, support the applicability of garlic oil in an integrated mosquito vector control program.
NSTL
Elsevier