MERCURY REDUCTASE ACTIVITY OF Azotobacter ISOLATES AS A REDUCING AGENT FOR MERCURIAL ION (Hg2
Anjar Lulu Sakinah
Urban Farm DB summary
Mercury is a highly toxic and hazardous heavy metal, and bacteria able to live in mercury-contaminated habitats — mercury-resistant bacteria, including Azotobacter — are known to exist. This study aimed to obtain superior Azotobacter isolates resistant to mercuric chloride (HgCl2) from land at the ITS (Institut Teknologi Sepuluh Nopember) Eco Urban Farming site — land where mercury contamination was present — and to determine mercury reductase enzyme activity as a bioreductant converting Hg2+ to Hg0. Isolation used selective Azotobacter agar media, resistance was tested by a slant-agar streak method containing HgCl2, and mercury reductase activity was analyzed using the MRA method and spectrophotometry at 340 nm. Ten HgCl2-resistant Azotobacter isolates were obtained; isolates A5 and A9 tolerated 10 mg/L HgCl2 with optimal growth and relatively high mercury reductase activity, showing a reduction capacity of ≥3 mg/L and a reduction efficiency above 70% at an HgCl2 concentration of 5 mg/L.