Phenotypic Biodiversity Of Silicate Bacteria Isolated From Saline-alkali Soil In The Worth Part Of China And Screening The High-efficient Strains

Forty-eight silicate bacteria was isolated from saline-alkali soil in the north part of China, together with the reference strain of B. mucilaginosus (AS1.232, VKPM B-7519T), B. edaphicus (VKPM B-7517T), and the morphology, physiological and biochemical characteristics were tested. All the strains were tested by numerical analysis of 63 phenotypic characteristics. The phosphorus and potassium releasing ability tested, and the relation between pH, the bacterial amount and the phosphorus releasing capacity, the potassium releasing capacity was performed.The results indicated that there was very diverse about the physiological and biochemical aspects among all the strains, such as morphology, utilization of different carbon sources, hydrolyzation of glutin, phenylalaninase, nitrate reduction, hydrolyzation of casein, NaCl tolerance and pH tolerance, phosphorus releasing ability, etc. The result of numeric analysis showed that these strains were divided into four groups at the level of 80% similarity.The group â…  was formed by 41 strains (including two reference strains, B. mucilaginosus AS 1.232 and VKPM B-7519T). Strains in group I produced sediment when growing in the liquid culture, and utilized the most tested carbon sources as sole carbon sources, and used KNO3 and (NH4)2SO4 as sole nitrogen sources. Urase reaction, and hydroxylation of casein is negative, but nitrate reaction is positive. At the level of 84% similarity, group I was further divided into three subgroups.The group â…¡ consisted of 6 strains (include reference strain B. edaphicus VKPM B-7517T). These strains formed small colony with weakly slime when growing on Ashby agar plate, and produced ivory-white in the liquid culture. Except Glycerol and laevulose. most tested carbon sources can be utilized as sole carbon sources well. These strains utilized the KNO3 as nitrogen source well, but not use (NH4)2SO4. Nitrate reaction is positive; Urase reaction is negative; the tolerant ability to NaCl and pH is worse than that of strains in Group â… .Strain S21-4 formed group â…¢ singly. When growing on Ashby agar plate, it formed large colonies with strong slime, and produced sediment when growing in liquid culture, and ability of utilize the tested carbon source is poor.The others were included in the group â…£. The characteristics were same as those ofstrains in the Group â…¡ when growing in the liquid culture. The ability of utilizing the laevulose is poor. Nitrate reduction is positive; the strains in this group had high concentration of NaCl tolerance and high pH tolerance. Some strains can grow at medium with 3% NaCl and pH10.Most of the silicate bacteria had good ability of releasing phosphorus, but bad ability of releasing potassium. About 58.9% strains could release potassium; strains S23-17 S23-24 are high-efficient strains for releasing phosphorus. However, strain S23-14 is high-efficient strain for releasing potassium.The results also indicated that the amount of releasing phosphorus and releasing potassium was positively correlated with the decreasing of pH, but not correlated with the increase of the bacterial amount during the fermentation process.