The chlorophyll ethanol-extracted silkworm excrement was hardly biologically reused or fermented by most microorganisms. However, partial extremely environmental halophiles were reported to be able to utilize a variety of inexpensive carbon sources to accumulate polyhydroxyalkanoates. In this study, by using the nile red staining and gas chromatography assays, two endogenous haloarchaea strains: Haloarcula hispanica A85 and Natrinema altunense A112 of silkworm excrement were shown to accumulate poly(3-hydroxybutyrate) up to 0.23 g/L and 0.08 g/L, respectively, when using the silkworm excrement as the sole carbon source. The PHA production of two haloarchaea showed no significant decreases in the silkworm excrement medium without being sterilized compared to that of the sterilized medium. Meanwhile, the CFU experiments revealed that there were more than 60% target PHAs producing haloarchaea cells at the time of the highest PHAs production, and the addition of 0.5% glucose into the open fermentation medium can largely increase both the ratio of target haloarchaea cells (to nearly 100%) and the production of PHAs. In conclusion, our study demonstrated the feasibility of using endogenous haloarchaea to utilize waste silkworm excrement, effectively. The introduce of halophiles could provide a potential way for open fermentation to further lower the cost of the production of PHAs.

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Resistant starch could be degraded by the fermentation of colonic microorganisms in the large intestine of mammals, but not in the small intestine. In this study, we established a novel strategy by using resistant starch as an endogenous marker to determine the glucose absorption of the small intestine of laboratory animals. By optimization of the classical enzymatic method of starch measurement, the demand for the sample weight was reduced by 90%. Moreover, the amount of resistant starch in normal feed was detectable without any extra addition. The value of small intestine glucose absorption of mice was similar when using resistant starch and titanium dioxide as inert markers. The fermentation of resistant starch by intestinal microorganisms in the small intestine was demonstrated not disturbing the detection of glucose absorption significantly. Artificial sweeteners exposed ICR mice showed different glucose absorption which indicated, first, resistant starch can be used as a novel endogenous marker in the small intestine of small animals; second, although glucose tolerance did not change in mice after short-term exposure to artificial sweeteners, there were significant changes in glucose absorption associated with it; third, the short-term exposure resulted in no significant change in glucose tolerance.