Biological Characterizations Of Bacterial Strains With The Ability Of Biological Iron Removal And Their Effect On Iron Dissolution

Quartz sand and K-feldspar are very important non-metal mineral materials and are widely used in galss, casting, ceramics, refractories, and other industry. In recent years, with the development in color glass shell and ultra high voltage electric porcelain industry and the increasing gentrification of ceramics for daily use, the demand for quartz sand and K-feldspar with high purity and low iron increases. Iron removal process for quartz sand and K-feldspar has received great attention for enterprises. In this study, we investigated the effect of 3 mineral-weathering bacterial strains on the Fe release from quartz sand and K-feldspar. Furthermore, the influence of nutrient condition on the effect of the Fe release from the minerals by the strains was also evaluated. It will be important for the optimization of iron removal process by the biological method.The biological characteristics of 3 mineral-weathering bacterial strains (Burkholderia sp. D110, Chitinophaga sp. JN246, and Panteno sp. X84) were investigated. The results showed that temperature range for growth was 4-42℃ for strains D110 and X84 and 15-42 ℃ for strain JN246. The pH range for growth was 5.0-9.5 for strains D110 and JN246 and 5.0-9.0 for strain X84. The salt concentration (NaCl %) range for growth was 0.0-6.0% for strains D110 and X84 and 0.0-3.5% for strain JN246. All of the strains could produce siderophores and strain X84 produced maximum amount of siderophores.The effect of the three strains on the Fe release from quartz sand and K-feldspar was evaluated under the low nutrition condition (BHm medium). The results showed that in the quartz sand dissolution process, strain JN246 grew best, the maximum OD600 was obtained at 3 days of incubation; however, strain X84 had the highest ability to release Fe from quartz sand, soluble Fe concentration in the culture solution was 14.2±1.7 μmol·L-increased by 5.4-fold compared to the control. In the K-feldspar dissolution process, strain JN246 grew best, the maximum OD600 was obtained at 20 days of incubation; however, strain X84 had the highest ability to release Fe from K-feldspar, soluble Fe concentration in the culture solution was 32.8±1.3 μmol·L-1 μmol·L-1, increased by 18-fold compared to the control. While the Fe concentration in the culture solution in the presence of strain JN246 was increased by 10-fold compared to the control.The bacterial strain JN246 with the ability to release Fe from the minerals was related most closely to Chitinophaga eiseniae YC6729T(98.5%), Chitinophaga. terrae KP01T (96.8%), and Chitinophaga. Jiangningensis JN53T(96.3%); It contained MK-7 as the major menaquinone and homospermidine as the major polymine. The main fatty acids of strain JN53T were iso-C15:0 (45.2%), C16:0 (10.1%), C16:ω5c (21.2%), and C16:1ω7c/C16:1ω6c (11.98%). The polar lipid profile contained phosphatidylethanolamine, unknown aminolipids and unknown lipids. The total DNA G+C content of strain JN246 was 48.8 mol%. The low level of DNA-DNA relatedness to other species of the genus Chitinophaga and the many phenotypic properties that distinguished strain JN246 from recognized species of this genus demonstrated that isolate JN246 should be classified as representing a novel species of the genus Chitinophaga. The name Chitinophaga qingshengii sp. nov. is proposed for this novel species.The novel Fe-dissolving Chitinophaga qingshengii sp. nov was used to compare the effect of the strain JN246 on the Fe release from the two minerals under low (BHm) and moderate (SSKM) nutrition condition. In the Fe release from quartz sand, strain JN246 grew better and had better ability to release Fe in the SSKM. Maximum amount of Fe concentration (16.9±1 μmol·L-1) was obtained at 20 days of incubation, increasing by 7-fold compared to the control. In the Fe release from K-feldspar, strain JN246 grew better in the SSKM, however, the strain JN246 had better ability to release Fe in the BHm. Maximum amount of Fe concentration (19.3±1 μmol·L-1) was obtained at 20 days of incubation, increasing by 10-fold compared to the control.