Detection of Paenibacillus polymyxa spores by fluorescent in situ hybridization (FISH) and its application in organic compost fermentation

This paper studies on the detection of Paenibacillus polymyxa SQR21 spores by fluorescent in situ hybridization (FISH) after treatments of chemical substance and germinant pretreatment. Pretreatment effect and surface structure was analyzed by scanning electron microscopy. The results show that pretreated P. polymyxa spores can be detected by FISH in less than 2 hour after pretreatments, and germinant pretreatment has higher hybridization efficiency and stronger signal than chemical substance pretreatment. The germinant pretreatment spores were intact, but the chemical pretreatment spores were lysed at different degree. FISH with germinant pretreatment was used to detect SQR21 spores fermented in pig slurry compost at the condition of water content 50% under 37℃. The spores were germinated and enlarged after 2 hours, vegetable cells became visible after 4 hours, and vegetable cells were dominant after 12 hours. Compared with plate counting method, FISH with germinant pretreatment reflected the number and the change of SQR21 spores in organic compost more accurately, and it will be applied in detection of Bacillus. sp in bio-organic fertilizer.