A new endophytic fungus, described herein as Cunninghamella saisamornae, was isolated from soil collected from Chiang Mai Province, Thailand. This species was distinguished from the previously described Cunninghamella species by the presence of a chlamydospore formation, the lack of a zygospore stage and a maximum growth temperature of 45°C. Multi-gene phylogenetic analysis of internal transcribed spacers (ITS) and large subunit (LSU) of the nuclear ribosomal DNA (rDNA), along with the translation elongation factor 1-alpha (tef-1) genes, support the finding that C. saisamornae is distinct from other species within the genus Cunninghamella. A full description, color photographs, illustrations and a phylogenetic tree showing the position of C. saisamornae are provided.

The contamination of paraquat (1,1′‐dimethyl‐4,4′‐bipyridylium dichloride) herbicide from the farming area has become a public concern in many countries. This herbicide harms to human health and negatively effects the soil fertility. Several methods have been introduced for the remediation of paraquat. In this study, 20 isolates of the paraquat‐tolerant fungi were isolated from the contaminated soil samples in northern Thailand. We found that isolate PRPY‐2 and PFCM‐1 exhibited the highest degradation activity of paraquat on synthetic liquid medium. About 80 and 68% of paraquat were removed by PRPY‐2 and PFCM‐1 respectively after 15 days of cultivation. Based on the morphological characteristic and molecular analysis, the fungal isolate PRPY‐2 and PFCM‐1 were identified as Aspergillus tamarii and Cunninghamella sp. respectively. The biosorption of paraquat on these fungal mycelia was also investigated. It was found that only 8–10% of paraquat could be detected on their mycelia, while 24–46% of paraquat was degraded by fungal mycelia. This is the first report on paraquat degrading ability by A. tamarii and Cunninghamella sp. It is demonstrated that these filamentous fungi are promising microorganisms available for remediation of paraquat contaminated environment.