Study On Optimum Fermentation Conditions For Elevation Of 1-deoxyrimycin (DNj) From Sericulture Biomass Fermented By Designated Microorganism

1-Deoxynorijimycin (DNJ) as a kind of polyhydroxy piperidines was also called iminosugar for its configuration similar with sugar. DNJ appeared to be useful in food and medicine for its potential biological activities, such as inhibition of abnormal elevation of plasma glucose, anti-virus and anti-tumor. Therefore, DNJ had long been of interest for its suppressing the plasma glucose content with general consents. Mulberry resource enriched in DNJ, which can prohibit the bioactivities of intestinal alpha-glucosidase in vivo, and whose content in sericulture biomass was considered as one of significant indexes for effect on inhibition of postprandial glycemia. From the perspectives of extraction of DNJ from the silkworm with proficiency and elevation of DNJ content in sericulture resource by fermentation, this study focused on diluted acid extraction of DNJ from silkworm with surface response methodology (RSM), investigated a advantageous strain with fermentation conditions optimized by PB design and RSM, which could enhanced the DNJ content to a large extent from mulberry leaves, and groped for a prospect for production of DNJ from other sericulture resource fermented by the specific microorganism. Based on the results of this study, it is foreseen that production of DNJ and sericulture development of deep level would have the performance improved. Main results are as the following:The formula of diluted acid extraction of DNJ from silkworm with RSM could expressed as Y= 0.47+ 0.054X₁ - 0.03X₂- 0.00925X₃+ 0.03X₁X₂- 0.07X₁X₃- 0.059X₂X₃- 0.013X₁² - 0.027X₂² + 0.024X₃² , Which was significant and could elucidate impact of extraction factors on DNJ content from silkworm. The optimal extraction conditions were defined as: 72.9℃, 3 hours for 18 minutes and 1:282 of solid to liquid. The DNJ extracted after optimization was 0.493%, while predicted value was 0.487%, reflecting the both was consent with each other. There were obvious mutual interactions among the extraction time, temperature and the ratio of material to liquid throughout Contour line plot and response surface graph of DNJ yield.In compare with eight strains as starter cultures, Ganoderma lucidum was defined as the candidate for the fermentation by conversion of mulberry leaves into DNJ. And then analyzing eight factors effects on yield of DNJ fermented by Ganoderma lucidum by Plackett-Burman design, the range of pH, content of potassium nitrate and inoculum size was utilized for the following study, that is to say, for the single factor assay. The regression model for the optimizing the fermentation conditions was expressed as Y=0.054-9.37×10-4X1+1.25×10-5X2+5×10-5X3- 9.75×10-4X1X2+ 1.5×10-4X1X3+6.5×10-4X2X3-7.32×10-3X 12 -9.27×10-3X 22 -7.25×10-3 X 32 , Which was significantly appropriate and could elucidate impact of fermentation factors on DNJ content from mulberry. The highest amount of DNJ yield (0.548%) from the incubation broth by Ganoderma lucidum, in which fermentation broth showed better performance than origin before fermentation, would be calculated by first order local deviation with equivalence to zero, when X1, X2 and X3 received 6.97, 0.81% and 2.00 ml, respectively. There were obvious mutual interactions among the ph range, content of potassium nitrate and the inoculum size throughout Contour line plot and response surface graph of DNJ yield, suggesting the model was reliable and feasible.The distribution of DNJ in mulberry was shown that most important independent parts were upper leaves, roots, middle leaves (equaled to cortex), bottom leaves in order by content, suggesting DNJ mostly was produced by the young leaves. In compare with three methods of drying silkworm powders, indicating that lyophilization was the best approach to deal with it, suggesting its structure would be greatly maintained by lyophilization and DNJ molecule would be degraded or denatured under hot-air involved circumstance the elevation of DNJ content fermented by microorganism from mulberry was more than from silkworm. In compare with the unfermented, the DNJ contents increased by 20.8% in mulberry and 6.9% in silkworm powder, respectively. The content of DNJ in feces before or after fermentation decreased swiftly during the 6 days, followed mildly for the rest of days till mounting, appearing to be lowest in feces on 4th day of fifth-instar larvae. And the DNJ yield in feces fermented by given microorganism was higher than one in feces primitive, 20 percent promotion in average. However, DNJ content in feces on 4th day of fifth-instar larvae advanced most, up to 40.8%. The circulation and excretion mechanism of DNJ accumulated by the larvae of Bombyx mori will be investigated for the further study.