Papers by Geraldine Wittwer
Journal of Industrial Microbiology & Biotechnology, 2019
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Ciencias Marinas, 2011
The early stages of culture of the Chilean scallop Argopecten purpuratus are affected by the mort... more The early stages of culture of the Chilean scallop Argopecten purpuratus are affected by the mortality attributed to the presence of pathogenic bacteria. The purpose of this study was to characterize the culturable bacteria present in larval cultures of A. purpuratus in the presence and absence of antibiotic (Tetracycline). Bacterial counts on marine agar from water, algal, and larval samples from the culture units were carried out. These counts were performed every three days during 20 days of incubation. The bacterial strains isolated from count plates were identified by 16S rDNA gene sequence analysis. Additionally, the total bacterial counts from culture water were determined by epifluorescence microscopy. Culturable bacterial counts of water samples ranged from 8 × 103 to 3 × 104 CFU mL–1. These counts represent from 3% to 18% of the total bacterial counts. The culturable bacterial counts in larvae were between 3 × 107 and 3 × 108 CFU g–1 and were on average higher in the absen...
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Ciencias Marinas
The early stages of culture of the Chilean scallop Argopecten purpuratus are affected by the mort... more The early stages of culture of the Chilean scallop Argopecten purpuratus are affected by the mortality attributed to the presence of pathogenic bacteria. The purpose of this study was to characterize the culturable bacteria present in larval cultures of A. purpuratus in the presence and absence of antibiotic (Tetracycline). Bacterial counts on marine agar from water, algal, and larval samples from the culture units were carried out. These counts were performed every three days during 20 days of incubation. The bacterial strains isolated from count plates were identified by 16S rDNA gene sequence analysis. Additionally, the total bacterial counts from culture water were determined by epifluorescence microscopy. Culturable bacterial counts of water samples ranged from 8 × 103 to 3 × 104 CFU mL1. These counts represent from 3% to 18% of the total bacterial counts. The culturable bacterial counts in larvae were between 3 × 107 and 3 × 108 CFU g1 and were on average higher in the absen...
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Annals of Microbiology, 2015
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Journal of industrial microbiology & biotechnology, Jan 30, 2018
The interest in and demand for natural dyes has increased significantly in recent years; however,... more The interest in and demand for natural dyes has increased significantly in recent years; however, very few natural blue dyes are commercially available, because blue colored compounds in nature are relatively rare. In this study, a blue pigment-producing bacteria from Lake Chungará (Atacama Desert, Chile) was isolated, and its blue pigment was purified and chemically characterized. The pigment-producing strain was identified as Pseudarthrobacter sp. by 16S rRNA gene sequencing. The pigment was separated from the filtered culture medium by column chromatography/solid-phase extraction using different resins (ionic exchange, C-18, size exclusion). The strain produced up to 2.5 g L of blue pigment, which was very soluble in water, partially soluble in methanol and insoluble in other organic solvents. The pigment was analyzed and characterized by analytical HPLC, UV-Vis, FT-IR, and H-NMR, and purified by semi-preparative HPLC. The pigment was non-toxic to brine shrimp (LD > 2.3 g L) a...
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Papers by Geraldine Wittwer