Isolation, stability, and characteristics of high-pressure superdormant Bacillus subtilis spores

Bacterial spores are a major challenge in industrial decontamination processes owing to their extreme resistance. High-pressure (HP) of 150 MPa at 37 °C can trigger the germination spores, making them lose Once resistance is lost, germinated easily be inactivated by mild step. The implementation this gentle germination-inactivation strategy hindered presence subpopulation so-called high-pressure superdormant (HPSD) which resist or germinate only very slowly response HP. It essential understand properties HPSD and underlying causes superdormancy tackle further develop strategies involving This study investigated factors influencing prevalence successfully isolated combining buoyant density centrifugation fluorescence-activated cell sorting, allowed characterisation for first time. was shown strongly dependent on HP dwell time, with increasing treatment times reducing prevalence. Spore mutants lacking germinant receptors showed highly increased spores; 93% remained dormant even after prolonged time 40 min. In contrast nutrient germination, sublethal heat 75 30 min prior pressure did not induce spore activation increase germination. show visible structural differences compared initial when transmission electron microscopy. Re-sporulated similar capacity indicating that most likely genetically different from rest population. Moreover, majority exposed second same treatment; however, lower than fact lost makes it unlikely there one factor determines whether germinates certain not. Instead, seems possible other reversible cumulative causes. improve understanding regard stability, capacity, potential superdormancy. knowledge will contribute development HP-based but effective control. • bacterial were isolated. microscopic structure, characterised. have size cortex width spores. due genetic change. cause transient.