With the aim to apply the beneficial microorganisms to peanut （groundnut （Arachis hypogaea）） growing in sandy soil of Binhdinh province in Vietnam, the paper was conducted to study the isolation, selection of N-fi...With the aim to apply the beneficial microorganisms to peanut （groundnut （Arachis hypogaea）） growing in sandy soil of Binhdinh province in Vietnam, the paper was conducted to study the isolation, selection of N-fixing, phosphate, potassium solubilizing and slime producing microorganism from sandy soil and peanut root samples, and evaluate the capability of selected isolates to adapt to the sandy soil condition. The isolation and selection of beneficial microbes were based on the biological activity of isolates, which was determined by acetylene reduction assay and nodulation on the peanut for Rhizobium spp., by testing the capability to solubilize Ca3（PO4）2 or fenspat in the growth medium for phosphate, potassium solubilizing microbes, and by measurement of the viscosity of Hansen medium for slime producing microorganism. All isolates were evaluated for the effectiveness on the nutrition uptake and growth of peanut by carrying out at the greenhouse and field experiments. To evaluate the adaptation of selected isolates to the sandy soil condition, the experiments were carried out in the laboratory to determine the microbial density in suitable medium, containing different NaCI concentrations or with different pH or at different temperatures. The results showed that rhizobial strain RA18 had an N-fixing activity value of 3,458 ＋ 10.95 nmol C2H2/plant and can supply 30% of N required for peanut. The bacterial strain P 1107 is able to solubilize phosphate and can increase phosphorus uptake by 30% in peanut. Further, inoculation of peanut with the bacterial strain S3.1 can save 30% required mineral potassium, and the Lipomyces strain PT5.1 can produce the slime, which can provide the sandy soil to keep moisture for 15 d longer than the control without the inoculation. All selected isolates are able to grow at temperatures from 20 ℃ to 35 ℃, pH from 4.5 to 6.0 and the salinity of 0.2%o-0.6%o NaCI, and can well adapt to the sandy soil conditions.展开更多
Microbial lipids derived from oleaginous yeast could be a promising resource for biodiesel and other oleochemical materials. The objective of this study was to develop an efficient bioconversion process from lignocell...Microbial lipids derived from oleaginous yeast could be a promising resource for biodiesel and other oleochemical materials. The objective of this study was to develop an efficient bioconversion process from lignocellulosic biomass to microbial lipids using three types of robust oleaginous yeast: T. oleaginosus, L. starkeyi, and C. albidus. Sorghum stalks and switchgrass were utilized as feed-stocks for lipid production. Among oleaginous yeast strains, T. oleaginous showed better performance for lipid production using sorghum stalk hydrolysates. Lipid titers of 13.1 g·L-1 were achieved by T. oleaginosus, using sorghum stalk hydrolysates with lipid content of 60% (wt·wt-1) and high lipid yield of 0.29 g·g-1, which was substantially higher than the value reported in literature. Assessment of overall lipid yield revealed a total of 14.3 g and 13.3 g lipids were produced by T. oleaginosus from 100 g of raw sorghum stalks and switchgrass, respectively. This study revealed that minimization of sugar loss during pretreatment and selection of appropriate yeast strains would be key factors to develop an efficient bioconversion process and improve the industrial feasibility in a lignocellulose-based biorefinery.展开更多
文摘With the aim to apply the beneficial microorganisms to peanut （groundnut （Arachis hypogaea）） growing in sandy soil of Binhdinh province in Vietnam, the paper was conducted to study the isolation, selection of N-fixing, phosphate, potassium solubilizing and slime producing microorganism from sandy soil and peanut root samples, and evaluate the capability of selected isolates to adapt to the sandy soil condition. The isolation and selection of beneficial microbes were based on the biological activity of isolates, which was determined by acetylene reduction assay and nodulation on the peanut for Rhizobium spp., by testing the capability to solubilize Ca3（PO4）2 or fenspat in the growth medium for phosphate, potassium solubilizing microbes, and by measurement of the viscosity of Hansen medium for slime producing microorganism. All isolates were evaluated for the effectiveness on the nutrition uptake and growth of peanut by carrying out at the greenhouse and field experiments. To evaluate the adaptation of selected isolates to the sandy soil condition, the experiments were carried out in the laboratory to determine the microbial density in suitable medium, containing different NaCI concentrations or with different pH or at different temperatures. The results showed that rhizobial strain RA18 had an N-fixing activity value of 3,458 ＋ 10.95 nmol C2H2/plant and can supply 30% of N required for peanut. The bacterial strain P 1107 is able to solubilize phosphate and can increase phosphorus uptake by 30% in peanut. Further, inoculation of peanut with the bacterial strain S3.1 can save 30% required mineral potassium, and the Lipomyces strain PT5.1 can produce the slime, which can provide the sandy soil to keep moisture for 15 d longer than the control without the inoculation. All selected isolates are able to grow at temperatures from 20 ℃ to 35 ℃, pH from 4.5 to 6.0 and the salinity of 0.2%o-0.6%o NaCI, and can well adapt to the sandy soil conditions.
文摘Microbial lipids derived from oleaginous yeast could be a promising resource for biodiesel and other oleochemical materials. The objective of this study was to develop an efficient bioconversion process from lignocellulosic biomass to microbial lipids using three types of robust oleaginous yeast: T. oleaginosus, L. starkeyi, and C. albidus. Sorghum stalks and switchgrass were utilized as feed-stocks for lipid production. Among oleaginous yeast strains, T. oleaginous showed better performance for lipid production using sorghum stalk hydrolysates. Lipid titers of 13.1 g·L-1 were achieved by T. oleaginosus, using sorghum stalk hydrolysates with lipid content of 60% (wt·wt-1) and high lipid yield of 0.29 g·g-1, which was substantially higher than the value reported in literature. Assessment of overall lipid yield revealed a total of 14.3 g and 13.3 g lipids were produced by T. oleaginosus from 100 g of raw sorghum stalks and switchgrass, respectively. This study revealed that minimization of sugar loss during pretreatment and selection of appropriate yeast strains would be key factors to develop an efficient bioconversion process and improve the industrial feasibility in a lignocellulose-based biorefinery.
