Cutinases are hydrolytic enzymes used by phytopathogenic fungi to gain entry into plants by breaking down the cuticular barrier of higher plants. Cutinase displayed hydrolytic activity not only towards cutin, the main...Cutinases are hydrolytic enzymes used by phytopathogenic fungi to gain entry into plants by breaking down the cuticular barrier of higher plants. Cutinase displayed hydrolytic activity not only towards cutin, the main component of the plant cuticle, but also towards a variety of soluble synthetic esters, insoluble triglycerides and polyesters. Therefore, cutinase was evaluated for use in the chemical, food and cotton bio-scouring industry and for synthetic fibers modification. This research examined the production and purification of extracellular cutinase from the phytopathogenic fungus Fusarium oxysporum. The addition of apple cutin or its hydrolysate to the fungus growth medium resulted in an enhanced secretion of cutinase into the extracellular fluid. Testing 1-hexadecanol as an alternative to natural cutin to induce cutinase production resulted in a high process yield under modified growth conditions. Cutinase enzyme production was followed by an optimized purification method for enzyme preparation using high-performance liquid chromatography and high-specificity 4-nitrophenyl (16-methyl sulfide ester) hexadecanoate (pNMSEH) cutinase substrate. Electrophoresis sodiumdodecyl sulfate-polyacrylamide and isoelectric focusing gels enabled the final separation and identification of the protein. The purified cutinase had an approximate molecular weight of 20 kDa and an isoelectric point of 4.7. The method presented here could be modified and used for cutinase production and purification in other microorganisms that exhibit cutinolytic activity.展开更多
Two kinds of micro organism, Arthrobacter sp. AX86(1,4 dehdrogenator)and Absidia sp. A28(11α hydroxylator)were used in this experiment.Two different fermentation techniques were performed to accomplish the multiple c...Two kinds of micro organism, Arthrobacter sp. AX86(1,4 dehdrogenator)and Absidia sp. A28(11α hydroxylator)were used in this experiment.Two different fermentation techniques were performed to accomplish the multiple conversional reactions for producing 16β methyl 11α,17α,21 trihydroxy 1,4 pregnadiene 3,20 dione(Ⅲ)from 16β methyl 3β,17α,21 trihydroxy 5α pregnane 20 one 21 acetate(I):1)To produce product(Ⅲ)by means of a two step fermentation method which were independently performed first by Arthrobacter and next by Absiaia, and 2)the product was obtained by a sequential fermentation system of aforesaid two micro organisms in a single fermentor without isolation of the intermediates from the mixture.Our results showed that in both fermentation systems high yield of product was obtained.However,according to the technical simplicity,shorter duration of fermentation cycle and efficient yield of product,the second method is better than the first one.展开更多
The optimal conditions of the conversion of 16α methyl 3β,17α,21 trihydroxy 5α pregnane 20 one 21 acetate to 16α methyl 11α,17α,21 trihydroxy 1,4 pregndiene 3,20 dione by the mixed cultures of Arthrobacter sp 8...The optimal conditions of the conversion of 16α methyl 3β,17α,21 trihydroxy 5α pregnane 20 one 21 acetate to 16α methyl 11α,17α,21 trihydroxy 1,4 pregndiene 3,20 dione by the mixed cultures of Arthrobacter sp 86 and Metarhizium sp 88 were studied.2%～4%( V/V )N,N dimethylformamide in the medium was used to dissolve the substrate.It could increase the conversion ability.Adding the mycelium of Metarhizium into the dehydrogenation reaction mixture during 0～28 hours had no influence on the conversion rate.The optimal concentration of mycelium was around 75 mg/mL wet weight.0.04%～0.06% CoCl 2·6H 2O inhibited the degradation of steroid nucleus so that the product was greatly accumulated.Under such condition the yeild of mixed microbial conversion was 67%.展开更多
Two novel constituents were isolated from the roots of Chinese medicinal herbs, Salvia miltiorrhiza. Their structures were determined by spectroscopic technique. The compounds were named 13,14-dihydroxy-15-methyl-benz...Two novel constituents were isolated from the roots of Chinese medicinal herbs, Salvia miltiorrhiza. Their structures were determined by spectroscopic technique. The compounds were named 13,14-dihydroxy-15-methyl-benzo[2,3-a]-7,7-dimethyl-12-oxa-tricyclo[4,4,21.4,0]dodecane(1) and 16-methyl-tropono[2,3-c]-7,7-dimethyl-12-oxa-tricyclo[4,4,21.4,0]dodecane(2).展开更多
文摘Cutinases are hydrolytic enzymes used by phytopathogenic fungi to gain entry into plants by breaking down the cuticular barrier of higher plants. Cutinase displayed hydrolytic activity not only towards cutin, the main component of the plant cuticle, but also towards a variety of soluble synthetic esters, insoluble triglycerides and polyesters. Therefore, cutinase was evaluated for use in the chemical, food and cotton bio-scouring industry and for synthetic fibers modification. This research examined the production and purification of extracellular cutinase from the phytopathogenic fungus Fusarium oxysporum. The addition of apple cutin or its hydrolysate to the fungus growth medium resulted in an enhanced secretion of cutinase into the extracellular fluid. Testing 1-hexadecanol as an alternative to natural cutin to induce cutinase production resulted in a high process yield under modified growth conditions. Cutinase enzyme production was followed by an optimized purification method for enzyme preparation using high-performance liquid chromatography and high-specificity 4-nitrophenyl (16-methyl sulfide ester) hexadecanoate (pNMSEH) cutinase substrate. Electrophoresis sodiumdodecyl sulfate-polyacrylamide and isoelectric focusing gels enabled the final separation and identification of the protein. The purified cutinase had an approximate molecular weight of 20 kDa and an isoelectric point of 4.7. The method presented here could be modified and used for cutinase production and purification in other microorganisms that exhibit cutinolytic activity.
文摘Two kinds of micro organism, Arthrobacter sp. AX86(1,4 dehdrogenator)and Absidia sp. A28(11α hydroxylator)were used in this experiment.Two different fermentation techniques were performed to accomplish the multiple conversional reactions for producing 16β methyl 11α,17α,21 trihydroxy 1,4 pregnadiene 3,20 dione(Ⅲ)from 16β methyl 3β,17α,21 trihydroxy 5α pregnane 20 one 21 acetate(I):1)To produce product(Ⅲ)by means of a two step fermentation method which were independently performed first by Arthrobacter and next by Absiaia, and 2)the product was obtained by a sequential fermentation system of aforesaid two micro organisms in a single fermentor without isolation of the intermediates from the mixture.Our results showed that in both fermentation systems high yield of product was obtained.However,according to the technical simplicity,shorter duration of fermentation cycle and efficient yield of product,the second method is better than the first one.
文摘The optimal conditions of the conversion of 16α methyl 3β,17α,21 trihydroxy 5α pregnane 20 one 21 acetate to 16α methyl 11α,17α,21 trihydroxy 1,4 pregndiene 3,20 dione by the mixed cultures of Arthrobacter sp 86 and Metarhizium sp 88 were studied.2%～4%( V/V )N,N dimethylformamide in the medium was used to dissolve the substrate.It could increase the conversion ability.Adding the mycelium of Metarhizium into the dehydrogenation reaction mixture during 0～28 hours had no influence on the conversion rate.The optimal concentration of mycelium was around 75 mg/mL wet weight.0.04%～0.06% CoCl 2·6H 2O inhibited the degradation of steroid nucleus so that the product was greatly accumulated.Under such condition the yeild of mixed microbial conversion was 67%.
文摘Two novel constituents were isolated from the roots of Chinese medicinal herbs, Salvia miltiorrhiza. Their structures were determined by spectroscopic technique. The compounds were named 13,14-dihydroxy-15-methyl-benzo[2,3-a]-7,7-dimethyl-12-oxa-tricyclo[4,4,21.4,0]dodecane(1) and 16-methyl-tropono[2,3-c]-7,7-dimethyl-12-oxa-tricyclo[4,4,21.4,0]dodecane(2).
