We described a novel polymer-lipase conjugate for high-efficient esterification of vitamin E using vitamin E and succinic anhydride as the substrates in nonaqueous media.In this work,the monomer,N-isopropylacrylamide(...We described a novel polymer-lipase conjugate for high-efficient esterification of vitamin E using vitamin E and succinic anhydride as the substrates in nonaqueous media.In this work,the monomer,N-isopropylacrylamide(NIPAM),was grafted onto Candida rugosa lipase(CRL)to synthesize poly(NIPAM)(pNIPAM)-CRL conjugate by atom transfer radical polymerization via the initiator coupled on the surface of CRL.The result showed that the catalytic efficiencies of pNIPAM-CRL conjugates(19.5-30.3 L·s^(-1)·mmol^(-1))were at least 7 times higher than that of free CRL(2.36 L·s^(-1)·mmol^(-1))in DMSO.It was attributed to a significant increase in Kcat of the conjugates in nonaqueous media.The synthesis catalyzed by pNIPAM-CRL co njugates was influenced by the length and density of the grafted polymer,water content,solvent polarity and molar ratio of the substrates.In the optimal synthesis,the reaction time was shortened at least 7 times,and yields of vitamin E succinate by pNIPAM-g-CRL and free CRL were obtained to be 75.4%and 6.6%at 55℃after the reaction for 1.5 h.The result argued that conjugation with pNIPAM induced conformational change of the lid on CRL based on hydrophobic interaction,thus providing a higher possibility of catalysis-favorable conformation on CRL in nonaqueous media.Moreover,pNIPAM conjugation improved the thermal stability of CRL greatly,and the stability improved further with an increase of chain length of pNIPAM.At the optimal reaction conditions(55℃and 1.5 h),pNIPAM-g-CRL also exhibited good reusability in the enzymatic synthesis of vitamin E succinate and kept~70%of its catalytic activity after ten consecutive cycles.The research demonstrated that pNIPAM-g-CRL was a more competitive biocatalyst in the enzymatic synthesis of vitamin E succinate and exhibited good application potential under harsh industrial conditions.展开更多
We studied some factors affecting the lipase production from candida rugosa, they mainly included medium compositions and culture condition.The result showed that the optimal medium compositions for lipase production ...We studied some factors affecting the lipase production from candida rugosa, they mainly included medium compositions and culture condition.The result showed that the optimal medium compositions for lipase production are 0.1% glucose 4.0% olive oil (carbon source),0.3% NH 4NO 3(nitrogen source),1.2%K 2HPO 4 and 0.4%MgSO 4·7H 2O.And the optimal culture condition is initial pH6.5,temperature 30℃,agitation 180r/min and time 60h. As a result, and the lipase activity could reach 19.5u/mL.Meanwhile we found that the surfactant could be helpful to the lipase production, and the optimal surfactant concentration was 0.03% GPE.The lipase activity was improved by more than 170% after we optimized the medium compositions and culture condition.While in a 5L fermentator, the lipase activity of fermentation broth could reach 33.5u/mL within 48 hours.展开更多
The stability of Candida rugosa lipase coated with glutamic acid didodecyl ester ribitol amide was investigated taking esterification of lauryl alcohol and lauric acid in isooctane as a model reaction. At 30C, the hal...The stability of Candida rugosa lipase coated with glutamic acid didodecyl ester ribitol amide was investigated taking esterification of lauryl alcohol and lauric acid in isooctane as a model reaction. At 30C, the half-life of the activity of the coated lipase was ca 10 h, the enzyme activity became less changed after 12 h and the residual activity was 39% of the initial value. The coated lipase obeyed a first-order deactivation model with a deactivation energy of 29.9J.mol-1.展开更多
The surfactant-coated Candida rugosa lipase was used as catalyst for hydrolysis of olive oil in two-phase system consisting of olive oil and phosphate buffer without organic solvent. For both the coated and native lip...The surfactant-coated Candida rugosa lipase was used as catalyst for hydrolysis of olive oil in two-phase system consisting of olive oil and phosphate buffer without organic solvent. For both the coated and native lipases,the optimal buffer/oil volume ratio of 1.0, aqueous pH 6.8 and reaction temperature 30℃ were determined. The maximum activity of the coated lipase was ca 1.3 times than that of the native lipase. The half-life of the coated lipase in olive oil and the native lipase in phosphate buffer was ca 9 h and 12 h, and the final residual activity was 27% and 20% of their initial values, respectively. The final substrate conversion by the coated lipase was ca 20% higher than that of the native lipase.展开更多
Synthesis biodiesel using biocatalyst is an emerging and attracting alternative process to replace the conventional process. However, biocatalyst is easy to be deactivated by alcohol, which is a reactant in biodiesel ...Synthesis biodiesel using biocatalyst is an emerging and attracting alternative process to replace the conventional process. However, biocatalyst is easy to be deactivated by alcohol, which is a reactant in biodiesel synthesis reaction. Therefore, it is needed to develop new method to maintain the activity and stability of the biocatalyst during reaction. New method to be developed is by changing the reaction route which is using alcohol to the reaction route which is not using alcohol. Route reaction of non alcohol can be done by changing the alkyl alcohol with alkyl acetate. Both have the same function as alkyl supplier during the reaction. In this research, methyl acetate was reacted with triglyceride from fried palm oil using Candida rugosa lipase in batch reactor. The reactants and products were analyzed using HPLC. The effect of operating factors such as enzyme concentration, substrates ratio, operating temperature and addition of inhibitor using free and immobilized enzyme were investigated. The experimental results showed that 89.6% of triglyceride from fried palm oil was converted to its corresponding methyl esters under the condition of 4% wt lipase based on substrate weight, 1/12 mol rasio of oil/methyl acetate after 50 hours reaction using immobilized lipase. Stability test indicated that the activity of the immobilized biocatalyst was still remained after three reaction cycles.展开更多
Lipase production by Candida rugosa was carried out in submerged fermentation.Plackett-Burman statisticalexperimental design was applied to evaluate the fermentation medium components.The effect of twelve medium compo...Lipase production by Candida rugosa was carried out in submerged fermentation.Plackett-Burman statisticalexperimental design was applied to evaluate the fermentation medium components.The effect of twelve medium components was studied in sixteen experimental trials.Glucose,olive oil,peptone and FeCl3·6H2O were found to have more significance on lipase production by Candida rugosa.Maximum lipase activity of 3.8 u mL-1 was obtained at 50h of fermentation period.The fermentation was carried out at optimized temperature of 3℃,initial pH of 6.8 and shaking speed of 120 r/min.Unstructured kinetic models were used to simulate the experimental data.Logistic model,Luedeking-Piret model and modified Luedeking-Piret model were found suitable to efficiently predict the cell mass,lipase production and glucose consumption respectively with high determination coefficient(R2).From the estimated values of the Luedeking-Piret kinetic model parameters,α and β,it was found that the lipase production by Candida rugosa is growth associated.展开更多
A screening of commercially available lipases for the synthesis of vitamin E succinate showed that lipase from Candida rugosa presented the highest yield. The synthesis of vitamin E succinate in organic solvents with ...A screening of commercially available lipases for the synthesis of vitamin E succinate showed that lipase from Candida rugosa presented the highest yield. The synthesis of vitamin E succinate in organic solvents with dif- ferent lgP values ranging from -1.3 to 3.5 was investigated. Of particular interest was that dimethyl sulfoxide （DMSO） with the lowest lgP exhibited the highest yield among all the organic solvents used. It suggests that lgP is incapable of satisfactorily predicting the biocompatibility of organic solvents due to the complexity of enzymatic reaction with hydrophilic and hydrophobic substrates in organic solvent. Effects of different operating conditions, such as molar ratio of substrate, enzyme concentration, reaction temperature, mass transfer, and reaction time were also studied. Under the optimum conditions of 10 g/L enzyme, a stirring rate of 100 r/min, a substrate molar ratio of 5：1 at 55℃ for 18 h, a satisfactory yield（46.95%） was obtained. The developed method has a potential to be used for efficient enzymatic production of vitamin E succinate.展开更多
An efficient lipase-catalyzed enantioselective hydrolysis of bu-tyryloxyalkanephosphonates in water-equilibrated diisopropyl ether was developed. The relationship between the substrates' structure and the reactivi...An efficient lipase-catalyzed enantioselective hydrolysis of bu-tyryloxyalkanephosphonates in water-equilibrated diisopropyl ether was developed. The relationship between the substrates' structure and the reactivity, as well as the enantioselectivity of this enzymatic transformation was studied. The catalytic preference of crude Candida rugosa lipase toward such molecules was assigned according to modified Mosher's method and X-ray crystallographic analysis. Optically pure 2-hydroxy-2-arylethanephosphonates, 3-hydroxy-3-phenylpropanephosphon-ate, and 3,3,3-trifluoro-2-hydroxypropanephosphonates were conveniently prepared in this manner.展开更多
The synthesis of a promising brain imaging agent 4-[F-18]fluoro-4-deoxy-N-acetyl-1,3,6-tri-O-acetylglucosamine, 2, was successfully accomplished from commercially available N-acetyl glucosamine in 5 steps. The non-dec...The synthesis of a promising brain imaging agent 4-[F-18]fluoro-4-deoxy-N-acetyl-1,3,6-tri-O-acetylglucosamine, 2, was successfully accomplished from commercially available N-acetyl glucosamine in 5 steps. The non-decay corrected radiochemical yield and purity were found to be 31% ± 4% (n = 3) and >98% respectively. The total reaction time for radio labelling step was 50 min.展开更多
基金financially supported by the National Key Research and Development Program of China (2021YFC2102801)National Natural Science Foundation of China (21878221)+1 种基金the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (21621004)the Haihe Laboratory of Sustainable Chemical Transformations for financial support.
文摘We described a novel polymer-lipase conjugate for high-efficient esterification of vitamin E using vitamin E and succinic anhydride as the substrates in nonaqueous media.In this work,the monomer,N-isopropylacrylamide(NIPAM),was grafted onto Candida rugosa lipase(CRL)to synthesize poly(NIPAM)(pNIPAM)-CRL conjugate by atom transfer radical polymerization via the initiator coupled on the surface of CRL.The result showed that the catalytic efficiencies of pNIPAM-CRL conjugates(19.5-30.3 L·s^(-1)·mmol^(-1))were at least 7 times higher than that of free CRL(2.36 L·s^(-1)·mmol^(-1))in DMSO.It was attributed to a significant increase in Kcat of the conjugates in nonaqueous media.The synthesis catalyzed by pNIPAM-CRL co njugates was influenced by the length and density of the grafted polymer,water content,solvent polarity and molar ratio of the substrates.In the optimal synthesis,the reaction time was shortened at least 7 times,and yields of vitamin E succinate by pNIPAM-g-CRL and free CRL were obtained to be 75.4%and 6.6%at 55℃after the reaction for 1.5 h.The result argued that conjugation with pNIPAM induced conformational change of the lid on CRL based on hydrophobic interaction,thus providing a higher possibility of catalysis-favorable conformation on CRL in nonaqueous media.Moreover,pNIPAM conjugation improved the thermal stability of CRL greatly,and the stability improved further with an increase of chain length of pNIPAM.At the optimal reaction conditions(55℃and 1.5 h),pNIPAM-g-CRL also exhibited good reusability in the enzymatic synthesis of vitamin E succinate and kept~70%of its catalytic activity after ten consecutive cycles.The research demonstrated that pNIPAM-g-CRL was a more competitive biocatalyst in the enzymatic synthesis of vitamin E succinate and exhibited good application potential under harsh industrial conditions.
文摘We studied some factors affecting the lipase production from candida rugosa, they mainly included medium compositions and culture condition.The result showed that the optimal medium compositions for lipase production are 0.1% glucose 4.0% olive oil (carbon source),0.3% NH 4NO 3(nitrogen source),1.2%K 2HPO 4 and 0.4%MgSO 4·7H 2O.And the optimal culture condition is initial pH6.5,temperature 30℃,agitation 180r/min and time 60h. As a result, and the lipase activity could reach 19.5u/mL.Meanwhile we found that the surfactant could be helpful to the lipase production, and the optimal surfactant concentration was 0.03% GPE.The lipase activity was improved by more than 170% after we optimized the medium compositions and culture condition.While in a 5L fermentator, the lipase activity of fermentation broth could reach 33.5u/mL within 48 hours.
基金Supported by the National Natural Science Foundation of China(No.29876031)
文摘The stability of Candida rugosa lipase coated with glutamic acid didodecyl ester ribitol amide was investigated taking esterification of lauryl alcohol and lauric acid in isooctane as a model reaction. At 30C, the half-life of the activity of the coated lipase was ca 10 h, the enzyme activity became less changed after 12 h and the residual activity was 39% of the initial value. The coated lipase obeyed a first-order deactivation model with a deactivation energy of 29.9J.mol-1.
基金National Natural Science Foundation of China(No.29876031)
文摘The surfactant-coated Candida rugosa lipase was used as catalyst for hydrolysis of olive oil in two-phase system consisting of olive oil and phosphate buffer without organic solvent. For both the coated and native lipases,the optimal buffer/oil volume ratio of 1.0, aqueous pH 6.8 and reaction temperature 30℃ were determined. The maximum activity of the coated lipase was ca 1.3 times than that of the native lipase. The half-life of the coated lipase in olive oil and the native lipase in phosphate buffer was ca 9 h and 12 h, and the final residual activity was 27% and 20% of their initial values, respectively. The final substrate conversion by the coated lipase was ca 20% higher than that of the native lipase.
文摘Synthesis biodiesel using biocatalyst is an emerging and attracting alternative process to replace the conventional process. However, biocatalyst is easy to be deactivated by alcohol, which is a reactant in biodiesel synthesis reaction. Therefore, it is needed to develop new method to maintain the activity and stability of the biocatalyst during reaction. New method to be developed is by changing the reaction route which is using alcohol to the reaction route which is not using alcohol. Route reaction of non alcohol can be done by changing the alkyl alcohol with alkyl acetate. Both have the same function as alkyl supplier during the reaction. In this research, methyl acetate was reacted with triglyceride from fried palm oil using Candida rugosa lipase in batch reactor. The reactants and products were analyzed using HPLC. The effect of operating factors such as enzyme concentration, substrates ratio, operating temperature and addition of inhibitor using free and immobilized enzyme were investigated. The experimental results showed that 89.6% of triglyceride from fried palm oil was converted to its corresponding methyl esters under the condition of 4% wt lipase based on substrate weight, 1/12 mol rasio of oil/methyl acetate after 50 hours reaction using immobilized lipase. Stability test indicated that the activity of the immobilized biocatalyst was still remained after three reaction cycles.
文摘Lipase production by Candida rugosa was carried out in submerged fermentation.Plackett-Burman statisticalexperimental design was applied to evaluate the fermentation medium components.The effect of twelve medium components was studied in sixteen experimental trials.Glucose,olive oil,peptone and FeCl3·6H2O were found to have more significance on lipase production by Candida rugosa.Maximum lipase activity of 3.8 u mL-1 was obtained at 50h of fermentation period.The fermentation was carried out at optimized temperature of 3℃,initial pH of 6.8 and shaking speed of 120 r/min.Unstructured kinetic models were used to simulate the experimental data.Logistic model,Luedeking-Piret model and modified Luedeking-Piret model were found suitable to efficiently predict the cell mass,lipase production and glucose consumption respectively with high determination coefficient(R2).From the estimated values of the Luedeking-Piret kinetic model parameters,α and β,it was found that the lipase production by Candida rugosa is growth associated.
基金Supported by the National High-Tech Research and Development Program of China（No.2011AA02A209）, the Key Project of National Natural Science Foundation of China（No.20936002） and the National Natural Science Foundation of China for Young Scholars（No.20906049）.
文摘A screening of commercially available lipases for the synthesis of vitamin E succinate showed that lipase from Candida rugosa presented the highest yield. The synthesis of vitamin E succinate in organic solvents with dif- ferent lgP values ranging from -1.3 to 3.5 was investigated. Of particular interest was that dimethyl sulfoxide （DMSO） with the lowest lgP exhibited the highest yield among all the organic solvents used. It suggests that lgP is incapable of satisfactorily predicting the biocompatibility of organic solvents due to the complexity of enzymatic reaction with hydrophilic and hydrophobic substrates in organic solvent. Effects of different operating conditions, such as molar ratio of substrate, enzyme concentration, reaction temperature, mass transfer, and reaction time were also studied. Under the optimum conditions of 10 g/L enzyme, a stirring rate of 100 r/min, a substrate molar ratio of 5：1 at 55℃ for 18 h, a satisfactory yield（46.95%） was obtained. The developed method has a potential to be used for efficient enzymatic production of vitamin E succinate.
基金Project supported by the National Natural Science Foundation of China(Nos.20272075,20072052).
文摘An efficient lipase-catalyzed enantioselective hydrolysis of bu-tyryloxyalkanephosphonates in water-equilibrated diisopropyl ether was developed. The relationship between the substrates' structure and the reactivity, as well as the enantioselectivity of this enzymatic transformation was studied. The catalytic preference of crude Candida rugosa lipase toward such molecules was assigned according to modified Mosher's method and X-ray crystallographic analysis. Optically pure 2-hydroxy-2-arylethanephosphonates, 3-hydroxy-3-phenylpropanephosphon-ate, and 3,3,3-trifluoro-2-hydroxypropanephosphonates were conveniently prepared in this manner.
文摘The synthesis of a promising brain imaging agent 4-[F-18]fluoro-4-deoxy-N-acetyl-1,3,6-tri-O-acetylglucosamine, 2, was successfully accomplished from commercially available N-acetyl glucosamine in 5 steps. The non-decay corrected radiochemical yield and purity were found to be 31% ± 4% (n = 3) and >98% respectively. The total reaction time for radio labelling step was 50 min.
