The mining and leakage of molybdenum (Mo) can cause environmental contamination which has not been realized until recently. Bacteria that can mitigate Mo-contamination was enriched and isolated. The low temperature and different pH conditions were considered to analysis its feasibility in Northern China which suffers from a long time of low temperatures every year. The result showed that the removal rate of MoO.sub.4.sup.2- by Raoultella ornithinolytica A1 reached 30.46% at 25 °C and pH 7.0 in Luria-Bertani medium (LB). Meanwhile, A1 also showed some efficiency in the reduction of MoO.sub.4.sup.2- in low phosphate molybdate medium (LPM), which reached optimum at the MoO.sub.4.sup.2- concentration of 10 mM. The results of FTIR indicated that the cell wall performed an essential role in the MoO.sub.4.sup.2- removal process, which was illustrated by the distribution of Mo in A1 (Mo bound to cell wall accounted for 92.29% of the total MoO.sub.4.sup.2- removed). In addition, low temperature (10 °C) effect the removal rate of MoO.sub.4.sup.2- by - 8.38 to 11.66%, indicating the potential for the in-situ microbial remediation of Mo-contaminated environments in low temperature areas. Graphical abstract