Microbial Taxonomic Study Of Two Novel Species,and Study Of Production Of Surfactants By Rhodococcus FDL2

The main contents of this research are polyphasic taxonomy study of Sphingomonas qilianensis sp.nov.,which was isolated from the permafrost region of Qilian Mountains,and polyphasic taxonomy study of Sphingorhabdus maotaiensis sp.nov.,which was isolated from Chishui River in section of Maotai Town.The genotype analysis analysis,phenotypic analysis and chemical classification were used to determine the taxonomic status of the new species.Strain X1T was isolated from the permafrost region of Qilian Mountains in northwest of China,which is belonging to the genus Sphingomonas,family Sphingomonadaceae.Cells are Gram-stain-negative,strictly aerobic,non-motile and rod-shaped,Colonies are light-yellow in colour,smooth,circular,convex.Strain X1T was able to grow at 15-30 ?,but not grow at 37 ?,at pH 6.0-10.0 and with 0-0.3%NaCl(w/v).The DNA G+C content of the isolate was 64.8 mol%.Strain X1T contained Q-10 as the dominant ubiquinone and C118:1?7c,C16:1 ?7c,C16:o and C14:0 2-OH as the dominant fatty acids.The polar lipid profile of strain XIT contained sphingoglycolipid,phosphatidylglycerol,phosphatidylethanolamine,one unidentified glycolipid,two unidentified phospholipid.Due to the phenotypic and genetic distinctiveness and other characteristic studied in this article,we consider X1T as a novel species of the genus Sphingomonas,and propose to name it Sphingomonas qilianensis sp.nov.The type strain is X1T(=CGMCC 1.15349T=KCTC 428621).Strain T5T was isolated from Chishui River in section of Maotai Town,Guizhou Province,Southwest of China.Cells are Gram-reaction-negative,strictly aerobic,non-motile and rod-shaped,Colonies are light-yellow in colour,smooth,circular,convex.Strain T5T grew optimally at pH 9.0 and 25?.Cells grow in the presence of 0%NaCl(w/v).The 16S rRNA gene sequence analysis indicated that strain T5T belonged to the family Sphingomonadaceae within the phylum Proteobacteria.The DNA G+C content was 58.5 mol%.The predominant respiratory quinone is Q-10.The major polyamine is spermidine.The major fatty acids are C18:1 ?7c,C16:1 ?7c.In addition to the major polar lipid phosphatidylethanolamine(PE),one unidentified glycolipid,three unidentified phospholipids,one unidentified aminophospholipid are also detected.According to the analysis results of genotype,phenotype and chemical characteristics,strain T5T was identified as a novel species,and the name Sphingorhabdus maotaiensis sp.nov was proposed.The type strain,T5T(= CGMCC 1.129291 = JCM 30114T).Strain FDL2 belong to Rhodococcus genus,the strain grew most well in olive oil(50 mL·L-1),yeast extract(2 g·L-1),polypeptone(10 g·L-1),MgSO4·H2O(1 g·L-1),glucose(10 g·L-1),KH2PO4(1 g·L-1),K2HPO4(8 g·L-1)medium.Strain FDL2 secreted 3 glycolipids,is a good biosurfactant,measured CMC was 42.7 mg·L-1,yCMC was 18.20 mN·m-1.