Simultaneous aerobic denitrification and Cr(VI) reduction by Pseudomonas brassicacearum LZ-4 in wastewater

• DOI: 10.1016/j.biortech.2016.09.037
• Publication Date: 2016-09-12T22:47:12Z
• Authors: Xuan Yu; Yiming Jiang; Haiying Huang; Juanjuan Shi; Kejia Wu; Pengyun Zhang; Jianguo Lv; Hongli Li; Huan He; Pu Liu; Xiangkai Li
• Keywords: Chromium; Nitrates; Nitrogen; 0211 other engineering and technologies; 02 engineering and technology; Wastewater; 6. Clean water; Water Purification; Bioreactors; Metals, Heavy; Pseudomonas; Denitrification

Inorganic nitrogen and heavy metals pervasively co-exist in industrial and domestic wastewaters. In this work, Pseudomonas brassicacearum LZ-4 was tested for the simultaneous reduction of Cr(VI) and nitrate. Nitrate was found to be the best inorganic nitrogen source for strain LZ-4, and could promote Cr(VI) reduction. Cr(VI) had a low degree of inhibition on denitrification, and even 50mgL-1 Cr(VI) did not inhibit reduction of 100mgL-1 NO3--N. The capability of simultaneous reduction of Cr(VI) and nitrate was illustrated by the reductase genes contained in the LZ-4 genome. Application in a batch membrane bioreactor showed that the immobilized strain LZ-4 could remove over 95% of 500mgL-1 NO3--N, 80% of 10mgL-1 Cr(VI), and 96% of 5000mgL-1 COD in each batch of 46days. In summary, the strain LZ-4 is an ideal candidate for remediation of co-contaminants.