The process of production of lactide from butyl lactate was investigated. The process consists of two stages： oligomerisation of butyl lactatean and depolymerisation of oligomers. The type catalysts of the series of ...The process of production of lactide from butyl lactate was investigated. The process consists of two stages： oligomerisation of butyl lactatean and depolymerisation of oligomers. The type catalysts of the series of Lewis acid were tested. It was found that SnCI4 is the most efficient catalyst for both stages.展开更多
This work reports detergents production using biological surfactants, microbiologically synthesized, and compares its foaming power and emulsification capacity to those presented by a petroleum based surfactant. Both ...This work reports detergents production using biological surfactants, microbiologically synthesized, and compares its foaming power and emulsification capacity to those presented by a petroleum based surfactant. Both used microorganisms were capable to produce surfactants, been able to emulsify oil/water mixtures and cause decrease of surface tension of water. The biosurfactant produced from Yarrowia lipolytica has a critical micelle concentration lower than that obtained from Pseudomonas aeruginosa （10 and 30 mg·Lt, respectively）, but the later showed better results in foaming power and emulsification experiments, similar to the synthetic detergent.展开更多
The good understanding of the mechanisms of resistance to herbicides in weeds is a necessity to implement sustainable weed management strategies. Here, a study was conducted to characterize the molecular bases of resi...The good understanding of the mechanisms of resistance to herbicides in weeds is a necessity to implement sustainable weed management strategies. Here, a study was conducted to characterize the molecular bases of resistance to acetyl coenzyme A carboxylase （ACCase） and acetolactate synthase （ALS） inhibiting herbicides in Lolium rigidum populations from Tunisia. Nine Lolium rigidum （ryegrass） populations collected in wheat fields from Northern Tunisia were investigated for their resistance to two ACCase-inhibiting herbicides and an ALS-inhibiting herbicide. All populations were tested in the greenhouse in pots using the commercial dose to determine resistance status. Survival plants were also tested for the presence of two ACCase （L 1781 and N2041） and two ALS （P197 and W574） mutant resistant alleles using molecular markers. Resistance to ACCase-inhibiting herbicides was found in all tested populations. Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 80% of the plants resistant to ACC-inhibiting herbicides would be resistant via increased herbicide metabolism. However, ALS-inhibiting herbicides are still more or less controlling ACCase resistant populations, so indicating that the selection process of resistance is ongoing. Target-site resistance appears to be the major mechanism for these early cases of ALS inhibitor resistance. This study reported the first case of resistance to ALS-inhibiting herbicides in ryegrass in Tunisia, and investigated the molecular bases of this resistance. It establishes the clear importance of non target-site resistance to ACCase- and/or ALS-inhibiting herbicides.展开更多
文摘The process of production of lactide from butyl lactate was investigated. The process consists of two stages： oligomerisation of butyl lactatean and depolymerisation of oligomers. The type catalysts of the series of Lewis acid were tested. It was found that SnCI4 is the most efficient catalyst for both stages.
文摘This work reports detergents production using biological surfactants, microbiologically synthesized, and compares its foaming power and emulsification capacity to those presented by a petroleum based surfactant. Both used microorganisms were capable to produce surfactants, been able to emulsify oil/water mixtures and cause decrease of surface tension of water. The biosurfactant produced from Yarrowia lipolytica has a critical micelle concentration lower than that obtained from Pseudomonas aeruginosa （10 and 30 mg·Lt, respectively）, but the later showed better results in foaming power and emulsification experiments, similar to the synthetic detergent.
文摘The good understanding of the mechanisms of resistance to herbicides in weeds is a necessity to implement sustainable weed management strategies. Here, a study was conducted to characterize the molecular bases of resistance to acetyl coenzyme A carboxylase （ACCase） and acetolactate synthase （ALS） inhibiting herbicides in Lolium rigidum populations from Tunisia. Nine Lolium rigidum （ryegrass） populations collected in wheat fields from Northern Tunisia were investigated for their resistance to two ACCase-inhibiting herbicides and an ALS-inhibiting herbicide. All populations were tested in the greenhouse in pots using the commercial dose to determine resistance status. Survival plants were also tested for the presence of two ACCase （L 1781 and N2041） and two ALS （P197 and W574） mutant resistant alleles using molecular markers. Resistance to ACCase-inhibiting herbicides was found in all tested populations. Comparison of the results from herbicide sensitivity bioassays with genotyping indicated that more than 80% of the plants resistant to ACC-inhibiting herbicides would be resistant via increased herbicide metabolism. However, ALS-inhibiting herbicides are still more or less controlling ACCase resistant populations, so indicating that the selection process of resistance is ongoing. Target-site resistance appears to be the major mechanism for these early cases of ALS inhibitor resistance. This study reported the first case of resistance to ALS-inhibiting herbicides in ryegrass in Tunisia, and investigated the molecular bases of this resistance. It establishes the clear importance of non target-site resistance to ACCase- and/or ALS-inhibiting herbicides.
