Pongsawat Pornsawan, Jianpinitnun Piyarat, Sasaki Satomi, Miyanishi Chizuru, Taniguchi Takako, Luangtongkum Taradon, Yasui Kentaro, Kinoshita Hiroyuki, Kobayashi Taichi, Nagahama Hideki, Yamada Kentaro, Misawa Naoaki
Laboratory of Veterinary Public Health, Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki, Japan.
Center for Animal Disease Control, University of Miyazaki, Miyazaki, Japan.
Appl Environ Microbiol. 2024 Sep 18;90(9):e0100724. doi: 10.1128/aem.01007-24. Epub 2024 Aug 23.
Akahoya is a volcanic soil rich in alumina, primarily deposited in Kyushu, Japan. We have found that Akahoya adsorbs bacteria in the water surrounding cattle grazing areas, suggesting a potential for environmental purification. This study investigated the spectrum of microorganisms adsorbed by Akahoya using a column filled with Akahoya through which a suspension of microorganisms was passed. Shirasu soil, another volcanic soil with a different chemical composition, was used as a control. Akahoya effectively adsorbed a diverse range of microorganisms including , , , Enteritidis, , , spores of and , severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), murine norovirus, and avian influenza virus (H3N2), whereas Shirasu soil did not adsorb any of the organisms examined. Moreover, bacteria naturally present in river water, such as aerobic bacteria, total coliforms, and as indicators of river contamination, as well as added artificially to sterilized river water, were reduced to below the detection limit (<1 CFU/mL) after being passed through Akahoya. Additionally, the number of viable continued to decrease after contact with Akahoya for 1 month, suggesting bactericidal effects. Notably, the adsorption of to Akahoya was influenced by the concentration of phosphate and the pH of the suspension due to the interaction between the surface phosphorylation of organisms and AlO, the major chemical component of Akahoya. The present results demonstrate the remarkable ability of Akahoya to remove phosphate and microbes, suggesting that Akahoya could be used for water purification processes.IMPORTANCEAlthough a safe and sufficient water supply is essential for the maintenance of hygienic conditions, a major challenge is to develop a comprehensive effective, sustainable, and cost-effective technological approach for the treatment and purification of contaminated water. In this study, we demonstrated that a novel volcanic soil, Akahoya, which has unlimited availability, is a highly effective adsorbent for a wide range of bacterial and viral pathogens, suggesting its potential as a sustainable resource for this purpose. It was suggested that the adsorption of microorganisms on Akahoya was mediated by phosphate groups present on the surface structures of microorganisms, which bind to the alumina component of Akahoya according to the phosphate concentration and pH of the liquid phase. The present findings highlight the exceptional ability of Akahoya to eliminate or reduce phosphate and microorganisms effectively in water purification processes, thus contributing to the development of efficient and sustainable solutions for addressing water pollution challenges.
赤堀土是一种富含氧化铝的火山土，主要分布在日本九州。我们发现，赤堀土能吸附牛放牧区周围水中的细菌，这表明它具有环境净化的潜力。本研究使用填充有赤堀土的柱子，让微生物悬浮液通过该柱子，从而研究了赤堀土吸附的微生物谱。另一种化学成分不同的火山土——白垩土用作对照。赤堀土能有效吸附多种微生物，包括肠炎沙门氏菌、艰难梭菌、产气荚膜梭菌、肠炎沙门氏菌、耐甲氧西林金黄色葡萄球菌、炭疽芽孢杆菌、肉毒杆菌芽孢、严重急性呼吸综合征冠状病毒2（SARS-CoV-2）、小鼠诺如病毒和禽流感病毒（H3N2），而白垩土对所检测的任何生物体都没有吸附作用。此外，河水中天然存在的细菌，如有氧细菌、总大肠菌群以及作为河流污染指标的粪大肠菌群，还有人工添加到灭菌河水中的粪大肠菌群，在通过赤堀土后减少到检测限以下（<1 CFU/mL）。此外，粪大肠菌群在与赤堀土接触1个月后活菌数量持续减少，表明有杀菌作用。值得注意的是，由于生物体表面磷酸化与赤堀土的主要化学成分氧化铝之间的相互作用，粪大肠菌群对赤堀土的吸附受磷酸盐浓度和悬浮液pH值的影响。目前的结果表明赤堀土具有显著的去除磷酸盐和微生物的能力，这表明赤堀土可用于水净化过程。重要性虽然安全充足的供水对于维持卫生条件至关重要，但一个主要挑战是开发一种全面有效、可持续且具有成本效益的技术方法来处理和净化受污染的水。在本研究中，我们证明了一种新型火山土——赤堀土，其来源丰富，是多种细菌和病毒病原体的高效吸附剂，表明其作为实现此目的的可持续资源的潜力。有人认为，微生物在赤堀土上的吸附是由微生物表面结构上存在的磷酸基团介导的，这些磷酸基团根据液相中的磷酸盐浓度和pH值与赤堀土的氧化铝成分结合。目前的研究结果突出了赤堀土在水净化过程中有效消除或减少磷酸盐和微生物的特殊能力，从而有助于开发应对水污染挑战的高效且可持续的解决方案。
