The outbreak of fungi in drinking groundwater sources can produce odor, cause toxicity and form lots of visible flocs, which seriously affect the drinking water quality. In this study, the inactivation efficiency of three dominant fungal spores Trichoderma, Penicillium, Cladosporium by chlorine was conducted, and the inactivation mechanism was explored by monitoring the hydrophobicity, the leakage of intracellular substances, the increase of extracellular adenosine triphosphate (ATP), deoxyribonucleic acid (DNA) and proteins, and the change of spores' morphology. The results showed that the inactivation of fungal spores was consistent with first-order kinetics and satisfied the Chick model. The resistance to chlorine was in sequence of Trichoderma > Penicillium > Cladosporium, the larger size the fungal spores and the more hydrophilicity the fungal spores, the higher the inactivation efficiency. Chlorination resulted in the remarkable leakage of intracellular compounds, the increase of extracellular characteristic compounds (ATP, DNA and protein), the damage of the cell surface, and the fungal spores recessed and wrinkled. In summary, chlorine firstly reacted with spores' surface and reduced their cultivability, and then resulted in the damage to the permeability barrier of the spores and the release of intracellular characteristic compounds, and finally the viability of spores was damaged.
Keywords: chlorine; fungal spores; hydrophobicity; inactivation mechanism; intracellular substance.