Abstract：
Though recombinant strains are increasingly recognized for their potential in heavy metal remediation, few studies have evaluated their safety. Moreover, biosafety assessments of fecal-oral pathway exposure at country as well as global level have seldom analyzed the health risks of exposure to microorganisms from a microscopic perspective. The present study aimed to predict the long-term toxic effects of recombinant strains by conducting a subacute toxicity test on the chromium-removal recombinant strain 3458 and analyzing the gut microbiome. The available disinfection methods were also evaluated. The results showed that strain 3458 induced liver damage and affected renal function and lipid metabolism at 1.0 × 1011 CFU/mL, which may be induced by its carrier strain, pET-28a. Strain 3458 poses the risk of increasing the number of pathogenic bacteria under prolonged exposure. When 500 mg L-1 chlorine-containing disinfectant or 250 mg L-1 chlorine dioxide disinfectant was added for 30 min, the sterilization rate exceeded 99.9 %. These findings suggest that existing wastewater disinfection methods can effectively sterilize strain 3458, ensuring its application value. The present study can serve a reference for the biosafety evaluation of the recombinant strain through exposure to the digestive tract and its feasibility for application in environmental pollution remediation.
摘要：
尽管重组菌株因其在重金属修复中的潜力而日益受到认可，很少有研究评估其安全性。此外，在国家和全球范围内对粪便-口腔途径暴露的生物安全性评估很少从微观角度分析暴露于微生物的健康风险。本研究旨在通过对去铬重组菌株3458进行亚急性毒性测试并分析肠道微生物组，预测重组菌株的长期毒性作用。还评估了可用的消毒方法。结果表明，在1.0×1011CFU/mL时，3458菌株可引起肝损伤，影响肾功能和脂质代谢。这可能是由其载体应变引起的，pET-28a.菌株3458具有在长时间暴露下增加病原菌数量的风险。当加入500mgL-1含氯消毒剂或250mgL-1二氧化氯消毒剂30min时,灭菌率超过99.9%。这些发现表明，现有的废水消毒方法可以有效地对3458菌株进行消毒，保证了其应用价值。本研究可为重组菌株消化道暴露的生物安全性评价及其在环境污染修复中应用的可行性提供参考。
