Identification,Culture Conditions Optimization of Nano-selenium Synthetic Bacteria lxz-41 and Its Application in Se-enriched Kiwifruit Cultivation

In this experiment,16S rDNA sequencing analysis and Biolog GenⅢ plate were used to identify a strain of lxz-41 with nano-selenium synthesis function. The medium composition and culture conditions of the synthesis of nanoselenium were optimized by the single factor and Box-Benhnken experiment with the sodium selenite as material,and the nano-selenium was applied in Kiwifruit cultivation. The results showed that the lxz-41 strain was identified as Bacillus amyloliquefaciens and was highly tolerant to sodium selenite. The optimal conditions for the synthesis of nano-selenium by lxz-41were as follows:4.5% sucrose,0.1% urea,1% yeast powder,0.3% dipotassium hydrogen phosphate,0.1% potassium dihydrogen phosphate,0.5% sodium chloride,0.15% sodium selenite,the initial pH was 7.0,the culture temperature was 40.5 ℃ and the rotation speed was 160 r/min.After culturing for 18 h at the condition,the highest conversion rate of nano-selenium was 86.8%±4.7%. The results of application in Kiwifruit showed that the nano-selenium indeed increased the content of selenium in flesh. The selenium content in flesh of Cui-Xiang was 0.050 mg/kg,and Hua-You was 0.035 mg/kg,and the rich selenium effect was better than inorganic selenium. This experiment provided a new way and technical basis for the preparation of nanoselenium from microbial and the cultivation of selenium-enriched crops.