Amorphophallus konjac is rich in glucomannan,which can be hydrolyzed into glucose and mannose,thereby acting as an economic raw material for the acquisition of glucose and mannose.The total sugar yield was 91.2%when k...Amorphophallus konjac is rich in glucomannan,which can be hydrolyzed into glucose and mannose,thereby acting as an economic raw material for the acquisition of glucose and mannose.The total sugar yield was 91.2%when konjac powder was treated with 0.75%hydrochloric acid at 121℃for 1 h.Thus,dilute acid hydrolysates of konjac powder were used as a carbon source for obtaining value-added products.Here we showed that the microbial production of ethanol and mannonic acid was obtained by employing Candida shehatae(C.shehatae)and Gluconobacter oxydans(G.oxydans).Through a step-by-step bioprocess,glucose is the first selectively converted to ethanol by C.shehatae,which enables G.oxydans-mediated biocatalysis of mannose to mannonic acid.Finally,approximately 100 g ethanol and 340 g mannonic acid were produced starting from 1 kg refined konjac powder.The results demonstrated the feasibility of this bioconversion method for producing mannonic acid starting from crude hydrolysates of konjac powder.展开更多
Xylose fermentation is essential for ethanol production from lignocellulosic biomass. Exposure of the xylose-fermenting yeast Candida shehatae （C. shehatae） CICC1766 to atmospheric pressure dielectric barrier discha...Xylose fermentation is essential for ethanol production from lignocellulosic biomass. Exposure of the xylose-fermenting yeast Candida shehatae （C. shehatae） CICC1766 to atmospheric pressure dielectric barrier discharge （DBD） air plasma yields a clone （designated as C81015） with stability, which exhibits a higher ethanol fermentation rate from xylose, giving a maximal enhancement in ethanol production of 36.2% compared to the control （untreated）. However, the biomass production of C81015 is lower than that of the control. Analysis of the NADH （nicotinamide adenine dinucleotide）- and NADPH （nicotinamide adenine dinucleotide phosphate）- linked xylose reductases and NAD＋-linked xylitol dehydrogenase indicates that their activities are enhanced by 34.1%, 61.5% and 66.3%, respectively, suggesting that the activities of these three enzymes are responsible for improving ethanol fermentation in C81015 with xylose as a substrate. The results of this study show that DBD air plasma could serve as a novel and effective means of generating microbial strains that can better use xylose for ethanol fermentation.展开更多
基金the financial support from the National Natural Science Foundation of China(31901270)the Scientific Research Start-up Funds of Nanjing Forestry University,China(163030127).
文摘Amorphophallus konjac is rich in glucomannan,which can be hydrolyzed into glucose and mannose,thereby acting as an economic raw material for the acquisition of glucose and mannose.The total sugar yield was 91.2%when konjac powder was treated with 0.75%hydrochloric acid at 121℃for 1 h.Thus,dilute acid hydrolysates of konjac powder were used as a carbon source for obtaining value-added products.Here we showed that the microbial production of ethanol and mannonic acid was obtained by employing Candida shehatae(C.shehatae)and Gluconobacter oxydans(G.oxydans).Through a step-by-step bioprocess,glucose is the first selectively converted to ethanol by C.shehatae,which enables G.oxydans-mediated biocatalysis of mannose to mannonic acid.Finally,approximately 100 g ethanol and 340 g mannonic acid were produced starting from 1 kg refined konjac powder.The results demonstrated the feasibility of this bioconversion method for producing mannonic acid starting from crude hydrolysates of konjac powder.
基金supported by National Natural Science Foundation of China(No.20576018)
文摘Xylose fermentation is essential for ethanol production from lignocellulosic biomass. Exposure of the xylose-fermenting yeast Candida shehatae （C. shehatae） CICC1766 to atmospheric pressure dielectric barrier discharge （DBD） air plasma yields a clone （designated as C81015） with stability, which exhibits a higher ethanol fermentation rate from xylose, giving a maximal enhancement in ethanol production of 36.2% compared to the control （untreated）. However, the biomass production of C81015 is lower than that of the control. Analysis of the NADH （nicotinamide adenine dinucleotide）- and NADPH （nicotinamide adenine dinucleotide phosphate）- linked xylose reductases and NAD＋-linked xylitol dehydrogenase indicates that their activities are enhanced by 34.1%, 61.5% and 66.3%, respectively, suggesting that the activities of these three enzymes are responsible for improving ethanol fermentation in C81015 with xylose as a substrate. The results of this study show that DBD air plasma could serve as a novel and effective means of generating microbial strains that can better use xylose for ethanol fermentation.
