| Summary: | 碩士 === 大葉大學 === 食品工程研究所 === 83 === Thuringiensin has a wide host spectrum affecting dipteran,
lepidopteran, coleopteran, and some other insects. Recently,
many efforts have been devoted to the research and
development of thuringiensin for using as a commercial
insecticide. Due to its low concentration in fermentation
broth and small molecular size, recovering of thuringiensin
is very challenging problem. In this study, a surfactant
cetylpyridinium chloride (CPC) was used to form micelle with
thuringiensin, which increased the overall molecu lar size of
CPC system including the adsorbed thuringiensin. Accordingly
an ultrafiltration step could be adopted to recover the
majority of thuringiensin in the broth. At the same time, the
surface tension of broth contain CPC will be change depend on
the surfactant concentration and twice achieve the critical
micelle concentration; At consider the effect of surfactant
on analyzing thuringiensin with HPLC method was cleared by a
supplementary photodiode array scanning, which showed only a
0.5 minute delay of retention time. The another test result
showed that the broth change the pH up and decreasing the
ionic strength will be increase this micellar-enhanced
ultrafiltration (MEUF) recovery rate; Finally, a novel
processing scheme was developed which included two steps in
series of micellar formation with CPC and ultrafiltration. Up
to 94.6% of thuringiensin was recovered in the final
retentate. The recovered solution had a high solid content,
which was fed directly to a spray drying. Bioassay results of
the product formulation showed that the control activity in
insects was the same as the fermentation broth. In
conclusion, the proposed MEUF process is effective in
recovering thuringiensin. The process was economic in energy
consumption, mild, and efficient; and thus, it has a good
potential for industrial application.
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