Biotite Weathering By The Mineral-Weathering Bacteria Isolated From The Different Environments In The Mica Mine Area And The Population Of The Mineral-Weathering Bacteria

Microorganisms are widely distributed in the various environments and play important role in the biogeochemical cycling of elements. The study focused on the mineral-weathering bacteria, their mineral-weathering ability, and their population structure in the different level of weathered mica schist as well as the rhizosphere and bulk soils of plants grown in the mine area. The study will provide the experiment basis for the interaction between minerals and bacteria and the roles of the bacteria in the mineral weathering and soil formation.Different level of weathered mica schist and rhizosphere and bulk soil samples were collected from the mica mine area in Susong, Anhui Province. Total 367 bacterial strains were obtained (271 strains from the weathered rocks and 96 strains from the soil samples) from the samples. Mineral weathering experiment showed that the ratios of the mineral-weathering bacteria from the highly, moderately, lowly-weathered rocks and rhizosphere and bulk soils were 90%,89%,80,72%, and 69%, respectively.16S rRNA gene sequence analysis showed that the mineral-weathering bacteria from the rocks belonged to 15 genera, among which Bacillus and Ochrobactrum were dominant. Bacillus, Burkholderia, Ochrobactrum, and Paenibacillus were common in the rocks. Brevibacillus, Curtobacterium, and Sinomonas were specific to the highly weathered rocks, Arthrobacter and Chitinophaga were specific to the moderately weathered rocks, and Cellulosimicrobium, Flavobacterium, and Rhizobium were specific to the lowly weathered rocks. The mineral-weathering bacteria from the rhizosphere soils belonged to Acinetobacter, Bacillus, Burkholderia and Paenibacillus, while the mineral-weathering bacteria from the bulk soils belonged to Bacillus, Burkholderia, Ochrobactrum, and Paenibacillus.In order to further investigate the biotite weathering by bacteria,4 isolates from the rocks and soil samples were used to evaluate the element release from biotite with time in the presence of the isolates. The results showed that the weathering ability of strain L307 from the lowly weathered rocks was highest. The strains could weather biotite through the organic acids produced by the strains. The main organic acids included tartaric, oxalic, citric, and succinic acids in the low nutrition condition, while the main organic acids produced by the strains included oxalic, citric, and succinic acids in the high nutrition condition. In addition, Si, Al, Fe, and K release were increased by 1.9-3.5,5.7-13,20-105, and 3.5-6.4-fold compared to the controls, respectively, in the presence of the strains under the low nutrition condition, while Si, Al, Fe, and K release were increased by 1.5-2.2,5.12, 11-69, and 3.7-5.7-fold compared to the controls, respectively, in the presence of the strains under the high nutrition condition.The strain M327 was related most closely to Paenibacillus terrigena A35T (98.65 16S rRNA gene sequence similarity) and Paenibacillus selenitireducens ES3-24T (98.3%). It contained MK-7 as the major menaquinone. The main fatty acids of strain M327 were anteiso-C15:0, iso-C16:0, and anteiso-C17:0.The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and phosphatidylethanolamine. The total DNA G+C content of strain M327 was 48.6 mol%. The low level of DNA-DNA relatedness to other species of the genus Paenibacillus and the many phenotypic properties that distinguished strain M327 from recognized species of this genus demonstrated that isolate M327 should be classified as representing a novel species of the genus Paenibacillus. The name Paenibacillus susongensis sp. nov. is proposed for this novel species.