A free-living, nitrogen-fixing, mesophilic and facultative aerobe, designated strain USBA 369, was isolated from a terrestrial saline spring of the Colombian Andes. The non-sporulating rods (1.5×0.8 µm) with rounded ends stained Gram-negative and were motile by means of lophotrichous flagella. The strain grew optimally at 30 °C, at pH 6.9-7.5 and with 1.5 % (w/v) NaCl. The major fatty acids detected were C18 : 1ω7c and C19 : 0 cyclo ω8c, and the respiratory lipoquinone ubiquinone 10 (Q-10) was present. The genome consisted of 4.65 Mb with a DNA G+C content of 64.3 mol%. A total of 4371 genes were predicted and, of those, 4300 were protein coding genes and 71 were RNA genes. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain USBA 369 formed a different lineage within the class Alphaproteobacteria, order Rhizobiales, and DNA homology studies with the most closely related genera, Aurantimonas, Aureimonas and Rhizobium (95 % 16S rRNA gene sequence similarity), showed values of <15 %. The phylogenomic analysis provided evidence for clear phylogenetic divergence between strain USBA 369 and the closely related genera. On the basis of the phenotypic, chemotaxonomic and phylogenomic evidence, strain USBA 369 is considered to represent a novel genus and a novel species for which the name Consotaella salsifontis gen. nov., sp. nov. is proposed. The type strain is USBA 369 (=KCTC 22549=CMPUJ U369).
Using Response Surface Methodology (RSM) we evaluated the culture conditions (nitrogen source, carbon source, pH and agitation rate) that increase the biomass of Acidocella facilis strain USBA-GBX-505 and therefore enhance the production of its lipolytic enzyme, 505 LIP. RSM results revealed that yeast extract and agitation were key culture factors that increased the growth-associated lipolytic activity by 4.5-fold (from 0.13 U.mg -1 to 0.6 U.mg -1). The 505 LIP lipase was partially purified using size-exclusion chromatography and ion-exchange chromatography. Its molecular weight was >77 kDa. The enzyme shows its optimum catalytic activity at 55 °C and pH 7.5. EDTA, PMSF, 1-butanol and DMSO inhibited enzymatic activity, whereas Tween 20, acetone, glycerol and methanol increased it. Metallic ions are not required for the activity of 505 LIP, and even have an inhibitory effect on the enzyme. This study shows the potential use of A. facilis strain USBA-GBX-505 for the production of a newly identified lipolytic enzyme, 505 LIP, which is stable at moderate temperatures and in the presence of organic solvents. These are important characteristics for the synthesis of many useful products.
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