[Objective] This study aimed to investigate the effects of different pretreat- ments on enzymatic saccharification of Miscanthus sinensis and improve reducing sugar yield in the enzymolysis process. [Method] M. sinens...[Objective] This study aimed to investigate the effects of different pretreat- ments on enzymatic saccharification of Miscanthus sinensis and improve reducing sugar yield in the enzymolysis process. [Method] M. sinensis was pretreated with 60Co y-ray irradiation and alkaline hydrogen peroxide, to analyze their effects on re- ducing sugar yield of enzymatic hydrolysis. [Result] After pretreatment with 400 kGy 60Co y-ray irradiation, reducing sugar yield in the enzymolysis process of M sinensis was 76.24 mg/g; after synergic pretreatment with 400 kGy 60Co y-ray irradiation and alkaline hydrogen peroxide, reducing sugar yield in the enzymolysis process of M. sinensis was 505.08 mg/g, which was improved by 5.6 times compared to that in pretreatment with 400 kGy 60Co y-ray irradiation. Based on process optimization, the optimal hydrolysis conditions were obtained： pretreatment temperature 30 ℃, NaOH concentration 1.2%, hydrogen peroxide concentration 2%, pretreatment time 6 h. [Conclusion] Synergic pretreatment with 60Co y-ray irradiation and alkaline hydrogen peroxide could significantly improve reducing sugar yield in the enzymolysis process of M. sinensis, which provided a new theoretical basis for preparing fuel ethanol with M. sinensis.展开更多
The mechanisms for fine-tuning ABA level related to grape berry ripening remain elusive. Here, transcription analysis showed that the mRNA expression level of 9-cis-epoxycarotenoid dioxygenase gene （VvNCED1） increas...The mechanisms for fine-tuning ABA level related to grape berry ripening remain elusive. Here, transcription analysis showed that the mRNA expression level of 9-cis-epoxycarotenoid dioxygenase gene （VvNCED1） increases first, rapidly in mesocarp before the onset of grape berry ripening. After VvNCED1 peaks its expression level, ABA content increases rapidly in mesocarp coupled with an increase in both soluble sugar content and pH value. On the onset of berry ripening, VvNCED1 transcripts decline rapidly to its lowest point, then increases slightly. Whereas, the mRNA expression level of B-glucosidase gene VvBGI, on the whole, increases constantly during grape berry ripening. During berry de-greening, ABA glucosyltransferase （VvGT） and ABA 8＇-hydroxylase （VvCYPI） equilibrate ABA level; during berry coloring-up, VvGT predominantly equilibrates ABA level, namely, the up-regulation of ABA level mainly leads from VvNCED1 and VvBG1 gene high expression; the down-regulation of ABA level leads mainly from VvCYP! transcript level both in ABA content- and developmental phase-dependence manner. In conclusion, our main results show that VvNCED1 and VvBG1 genes are closely related to grape berry ripening.展开更多
基金Supported by National High Technology Research and Development Program of China(863 Program)(2012AA101804)~~
文摘[Objective] This study aimed to investigate the effects of different pretreat- ments on enzymatic saccharification of Miscanthus sinensis and improve reducing sugar yield in the enzymolysis process. [Method] M. sinensis was pretreated with 60Co y-ray irradiation and alkaline hydrogen peroxide, to analyze their effects on re- ducing sugar yield of enzymatic hydrolysis. [Result] After pretreatment with 400 kGy 60Co y-ray irradiation, reducing sugar yield in the enzymolysis process of M sinensis was 76.24 mg/g; after synergic pretreatment with 400 kGy 60Co y-ray irradiation and alkaline hydrogen peroxide, reducing sugar yield in the enzymolysis process of M. sinensis was 505.08 mg/g, which was improved by 5.6 times compared to that in pretreatment with 400 kGy 60Co y-ray irradiation. Based on process optimization, the optimal hydrolysis conditions were obtained： pretreatment temperature 30 ℃, NaOH concentration 1.2%, hydrogen peroxide concentration 2%, pretreatment time 6 h. [Conclusion] Synergic pretreatment with 60Co y-ray irradiation and alkaline hydrogen peroxide could significantly improve reducing sugar yield in the enzymolysis process of M. sinensis, which provided a new theoretical basis for preparing fuel ethanol with M. sinensis.
基金This study is supported by China National Nattu-al Science Foundation （Project 31040006） and Beijing Natural Science Foundation and Scientific Research Key Program of Beijing Commission of Education （NO. KZ200910020001）.
文摘The mechanisms for fine-tuning ABA level related to grape berry ripening remain elusive. Here, transcription analysis showed that the mRNA expression level of 9-cis-epoxycarotenoid dioxygenase gene （VvNCED1） increases first, rapidly in mesocarp before the onset of grape berry ripening. After VvNCED1 peaks its expression level, ABA content increases rapidly in mesocarp coupled with an increase in both soluble sugar content and pH value. On the onset of berry ripening, VvNCED1 transcripts decline rapidly to its lowest point, then increases slightly. Whereas, the mRNA expression level of B-glucosidase gene VvBGI, on the whole, increases constantly during grape berry ripening. During berry de-greening, ABA glucosyltransferase （VvGT） and ABA 8＇-hydroxylase （VvCYPI） equilibrate ABA level; during berry coloring-up, VvGT predominantly equilibrates ABA level, namely, the up-regulation of ABA level mainly leads from VvNCED1 and VvBG1 gene high expression; the down-regulation of ABA level leads mainly from VvCYP! transcript level both in ABA content- and developmental phase-dependence manner. In conclusion, our main results show that VvNCED1 and VvBG1 genes are closely related to grape berry ripening.
