Novel hybrid materials on the basis of nanostructured tin dioxide and a lipase from rhizopus delemar with improved enantioselectivity

International audienceWe obtained novel hybrid materials on the basis of covalently bounded to amino-grafted tin dioxide lipase from Rhizopus delemar (NH2-nano-SnO2-RhD). Under the optimal condition, the protein loading yielded of 14.7 mg/g NH2-nano-SnO2, while the adsorption capacity of the unmodified nano-SnO2 for the same enzyme was 38.5 mg/g. At the same time, NH2-nano-SnO2-RhD exhibited specific hydrolytic activity of 77.6 U/mg prot. which is 2.5-fold higher in comparison to that of the physically adsorbed on nano-SnO2 lipase (nano-SnO2-RhD). In ten reaction cycles of tributyrin hydrolysis, up to 70% of the activity of NH2-nano-SnO2-RhD was preserved. Upon immobilization the enantioselectivity of the lipase for the reaction of acylation of (±)-menthol was improved. For the two biocatalysts, the highest yield of (−)-menthyl acetate (more than 35%) was obtained when glyceryl triacetate was used as acylating reagent, however, the enantiomeric excess was only 89.5% for the covalently bonded lipase and 85.0% for the physically adsorbed one. Higher enantiomeric excess was obtained when vinyl acetate was used as an acylating reagent; however, the conversion in that case did not exceed 20%. The addition of small amounts of pyrrolidinium-based ionic liquids, 1-methyl-1-octyl-pyrrolidinium bis(trifluoromethyl)sulfonyl imide [MOPyrro][NTf2], 1-methyl-1-octyl-pyrrolidinium hexafluorophosphate [MOPyrro][PF6], and 1-methyl-1-octyl-pyrrolidinium tetrafluoroborate [MOPyrro][BF4], to the reaction mixture resulted in decrease of (±) menthol conversion rate. All tested ionic liquids enhanced the enantioselectivity of nano-SnO2-RhD, and the best result was obtained in presence of [MOPyrro][PF6] (enantiomeric ratio >140)

Heterosis manifestations by survival and larval duration of F Bombyx mori L. Hybrids reared 1 with artificial diet

Abstract. The aim of this paper was to study the influence of the degree of heterosis (compared to higher parent value- HP and mean parental values- MP) on the signs, survival and duration of development in F hybrids of Bombyx mori L. from different geographical origin, fed by artificial diet. The study was conducted 1 at the Training Experimental Station of the Sericulture section of the Faculty of Agriculture at Trakia University. A total of 10 hybrids were tested featuring 6 breeds from the genetic bank of Sericulture and Agriculture Experiment Station (SAES)-Vratsa. Silkworms were reared with artificial diet containing 15% powder of dried mulberry leaf produced at SAES-Vratsa and prepared by methods, developed by the manufacturer, whereby 250g of dry substance and 675ml of distilled water are homogenized using a mixer. The mixture is cured thermally in a microwave for 10min. at ~800W. The receptivity of specimens was -st determined based on the results from the survival and the duration in the I age of the larval stage. In heterogeneous crossbreds higher survival rate in the first age is exhibited by hybrids in which a Japanese type breed was used as dam. Homogeneous crossbreds created with the participation of Japanese breeds excel in both analyzed traits those involving a Chinese type. For the survival trait heterosis manifestations to higher parent value (HP) and mean parental values (MP), were detected in the majority of hybrids (90.91%). Regarding the duration of development, heterosis effect to MP was observed in all F hybrids, 1 while to HP heterosis is exhibited by 60% of the tested F hybrids

Novel hybrid materials on the basis of nanostructured tin dioxide and a lipase from rhizopus delemar with improved enantioselectivity

International audienceWe obtained novel hybrid materials on the basis of covalently bounded to amino-grafted tin dioxide lipase from Rhizopus delemar (NH2-nano-SnO2-RhD). Under the optimal condition, the protein loading yielded of 14.7 mg/g NH2-nano-SnO2, while the adsorption capacity of the unmodified nano-SnO2 for the same enzyme was 38.5 mg/g. At the same time, NH2-nano-SnO2-RhD exhibited specific hydrolytic activity of 77.6 U/mg prot. which is 2.5-fold higher in comparison to that of the physically adsorbed on nano-SnO2 lipase (nano-SnO2-RhD). In ten reaction cycles of tributyrin hydrolysis, up to 70% of the activity of NH2-nano-SnO2-RhD was preserved. Upon immobilization the enantioselectivity of the lipase for the reaction of acylation of (±)-menthol was improved. For the two biocatalysts, the highest yield of (−)-menthyl acetate (more than 35%) was obtained when glyceryl triacetate was used as acylating reagent, however, the enantiomeric excess was only 89.5% for the covalently bonded lipase and 85.0% for the physically adsorbed one. Higher enantiomeric excess was obtained when vinyl acetate was used as an acylating reagent; however, the conversion in that case did not exceed 20%. The addition of small amounts of pyrrolidinium-based ionic liquids, 1-methyl-1-octyl-pyrrolidinium bis(trifluoromethyl)sulfonyl imide [MOPyrro][NTf2], 1-methyl-1-octyl-pyrrolidinium hexafluorophosphate [MOPyrro][PF6], and 1-methyl-1-octyl-pyrrolidinium tetrafluoroborate [MOPyrro][BF4], to the reaction mixture resulted in decrease of (±) menthol conversion rate. All tested ionic liquids enhanced the enantioselectivity of nano-SnO2-RhD, and the best result was obtained in presence of [MOPyrro][PF6] (enantiomeric ratio >140)