Identification of Cadmium-tolerant Bacteria from Cd-Contaminated Rice Fields Based on Biochemical dan Molecular Characters

A number of cadmium (Cd)-tolerant bacterial isolates were successfully obtained from Cd-contaminated irrigated rice fields in Banyumas Regency, Central Java Province, Indonesia. Bacterial isolates can reduce Cd levels up to 70 percent. Bacterial isolates have the potential to be used as bioremediation agents for Cd-contaminated land. Potential bacterial isolates need to be identified. The purpose of the study was to identify Cd-tolerant bacterial isolates based on biochemical and molecular characters. Biochemical characters of potential bacterial isolates were obtained through a number of tests such as oxidase, catalase, urease, glucose fermentation, motility, starch hydrolysis, and indole production. Molecular characters were obtained through 16S rDNA sequencing. The results showed that five bacterial isolates showed positive results for biochemical characters such as oxidase, motility, and starch hydrolysis. The five isolates showed negative results for biochemical characters such as catalase, urease, H2S production, and indole. For glucose fermentation test, only isolate PLK1 showed negative results. 16S rDNA molecular characters show that bacterial isolates GML2, KBS1, and SRU2 are close to Priestia megaterium , while isolate JTl1 with Neobacillus ginsengisoli , and PLK1 with Gottfriedia sp. Biochemical and molecular characters can be used to identify potential bacterial bioremediators of Cd-contaminated land.