Isolation and identification of a humic substances and Fe(III)-reducing bacterial strain

A facultative anaerobic bacterium,designated CY01,was isolated from a primitive forest sample collected from Sihui,Guangdong,China.Strain CY01 is a highly efficient humic substances and Fe(Ⅲ)-reducing bacterium.It is a gram-negative,non-motile,non-flagella,rod-shaped(1.2～1.5μm long,0.3～0.4μm wide),oxidase and catalase-positive(under aerobic growth conditions) bacterium.Analysis of 16S rDNA of CY01 indicated that the isolate formed a monophyletic clade with the members of the genus Comamonas. The closest phylogenetic relative among the valid species was Comamonas Koreensis,with 98%16S rDNA similarity.The(G+C) mol content of the DNA is 64.8.Tested by using the Biolog GN2 system,the strain could utilize 38 carbohydrates of 96 carbohydrates under aerobic growth condition.The isolate was identified as a strain of Comamonas Koreensis based on its biochemical,physiological and morphological characteristics as well as the analysis of 16s rDNA sequence and the DNA G+C content.The humic substances and Fe(Ⅲ)-reducing of Comamonas is here reported for the first time.